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A Salty First Kiss

Chapter Text

Izuku skipped around near the water’s edge as the summer sun peeked through the clouds, loving the feeling of the sand between his bare toes. It was a slow, late morning at the beach. There were a couple of other families and some high school-aged boys playing beach volleyball. The lifeguard sitting up on his elevated deck watched over a dozen or so people wading into the protected stretch of the ocean. The buoys dipped under the surf with each hefty wave. A couple of nearby high school girls in bikinis giggled at Izuku, causing him to blush and skirt the other direction.

Even though Dagobah Park Beach wasn’t too far away, only an hour and a half bus ride, this was the first time he had ever visited. It was also the first time he had seen the ocean with his own eyes, not on a screen or in some pictures. It was amazing, even if supposedly it wasn’t an ideal beach day with the cold front rolling in that evening. The deep blue waves lapping the pristine sand were calling him.

“Oh, Izuku!” his mom called. He turned his head to look at her while she struggled to set up the oversized red and yellow umbrella against the wind. “Don’t go too far now. I still have to put on your sunscreen!”

Izuku smiled. “Okay, Mom.” He ran over to his mom and helped her with the umbrella.

"Thank you, Sweetie," she said. After they firmly placed the umbrella, Izuku kneeled in the shade and allowed Mom to smear the cool sunscreen on his shoulders and down his back. He could hardly believe he was here, let alone that his father had been the one to suggest it. His dad was always working overseas, so he barely got to see him. He even missed his birthday last month even though he said he was going to be there. But he was nine years old and he was a big boy now; he knew how important his dad’s work overseas was. So despite his initial disappointment, Izuku told his mom that he didn't mind, that he understood. That was why he was so happy when he heard his dad was finally able to visit them and have a family beach trip.

“Aaaand there we go, Sweetie!” Mom said, kissing the top of his bushy hair.

“Mom!” Izuku blushed. His hands flew up to cover his head. He looked around the beach to see if anyone saw, but luckily for him, everyone seemed to be busy doing their own thing.

“What?” she said sweetly. “I don’t want my baby boy to get burnt!”

“Izuku,” his father’s deep voice called out, making both green-haired Midoriyas jump and look to the man as he returned from taking a business call. He shuffled at their expectant looks. "Let's, um, go for a walk?" he asked Izuku awkwardly, tilting his head back toward the rock outcropping at the far end of the beach.

Izuku smiled. "Okay!" He looked back to his mother. "I'll be back later!"

"Okay, sweetie," Mom said softly. She was smiling, but she sternly eyed her husband as she let them go.

As they set off, Izuku peeked up at his father from his peripheral vision. He had his bushy hair and freckles, but otherwise he was nearly a direct copy of Mom down to his baby face. “Um, where are we going?”

“Just walking the beach so we can… talk?” he said, rubbing the back of his head as they continued walking. Izuku huffed to keep up the pace. Every one stride for Dad was one and a half of his. “How’s soccer going?”

“I…” Izuku shrunk, looking down to the bright sand. He didn’t know much about his father, but he did find a photo of him playing soccer in high school. He had such a big grin on face, so Izuku thought if he picked up soccer, they would have something to bond over and maybe… maybe he would smile the same way he does in those pictures. But… “I haven’t played in over a year and a half,” he answered honestly. It wasn’t like he didn’t like it, but he was being bullied by the other players and Mom pulled him out after he came home crying one too many times.


“Yeah.” Silence fell between the two as they continued walking. After a few minutes, Dad tried asking more questions to start a conversation, but it only proved how little his father knew about him.

“How is school?”

“Fine,” other than I’m the residential punching bag.

“You still hang out with Monoma?”

“I see him every day,” as he is calling me a useless waste of space.

Izuku looked around. They were getting to a much more isolated part of the beach. They walked through a rock formation in the overhanging cliffside that brought them into an entirely distinct area. His eyes followed a small path that leads up the shallow cliffside to a large white house that screamed AFFLUENT. He’d know. He saw it in the dictionary.

Wait, was this a private beach?

Izuku’s heart fluttered in his chest. Were they trespassing? He looked up at his father, but he didn’t seem fazed… so maybe this was okay and he was just over thinking things.

“Wow, I didn’t know there was a pier back here,” Dad said, drawing Izuku’s attention to the narrow concrete pier pressed running parallel to the natural peninsula. “You want to walk it?” Dad looked down to him with a small, nervous smile.

Izuku looked around for a moment longer. No one seemed to be around except the two of them, but that didn’t mean it was okay to be here. He looked over to the pier. It was pretty long, but it looked heavy and solid. The metal was wrapped around it, and it was further surrounded by large stones and a chain rope fence set into the concrete around its edges. How much further could he see from the end of it, he wondered. He turned back to meet his father’s eyes again and nodded.

His father nodded in return and started towards the pier, Izuku hot on his tail. The concrete was rough on his bare feet, years of wear causing cracks to form and create depressions that water gathered in. “So,” his father started as they reached the halfway point, “how do you like the beach so far?”

Izuku’s eyes sparkled as he watched the waves crash into the rocks. The mist they created tickled his nose. As they continued further, Izuku noticed the waves were getting stronger as the wind was picking up between the natural rocky peninsula and pier. “I like it.”

“You want to go swimming later?” Dad asked. “Of course when we get back to the swimming area.”

“Yes!” Izuku said excitedly. He had been taking classes recently. He wasn't very good yet, at all, but he really wanted to splash into the salty waves. Supposedly it was easier to float in salt water than fresh, and he wanted to see if it was true.

His dad whistled. “Just look at this,” he said as they reached the end. The vast ocean shimmered in front of them.

“It’s amazing, isn’t it?” Izuku asked, smiling up at Dad before turning his attention back to the waves. “Just imagine what’s out there, Dad! We’re learning about it in school. Seventy percent of the Earth’s surface is covered with water, but that’s not even the cool part about it, we’ve only explored about five percent of our planet’s oceans. We only know a small fraction of all of the marine species, but it’s estimated over ninety percent of Earth’s living species live in the oceans. There is so much we yet to learn about our own planet.”

Dad chuckled hardly. “You looking to be an Oceanographer?”

“I…” Izuku blushed.

“Or maybe you want to be like that All Mighty person on the TV?”

“All Might,” Izuku corrected with a small voice. All Might was Toshinori Yagi’s television stage name of sorts. He was a big man with an even bigger heart who traveled around the world with a smile on his face. His show consisted of teaching children (and sometimes adults) the importance of taking care of the planet and being good to all people and creatures. He was his and many other people's hero.

“We should take a picture for your mother,” his dad said, patting his shorts’ pockets. His eyes widened and he pats his other pockets. “Where did I put it? Shit, did I drop it?” He even clapped his hand to his chest pocket even though it obviously didn’t hold his phone. “That was my work phone.” He looked panicked around, his feet itching back down the pier before his eyes landed on Izuku. He kneeled down to Izuku’s level, hands on his shoulders. “Izuku… stay here. I’m going to go look.” He looked over his shoulder. “It should only take a couple of minutes.” He stood and started to run down the pier, but turned back briefly to shout, “Stay there and don’t talk to any strangers!”

And then he was off, leaving Izuku again. He turned back to the ocean. His fears started to prickle on his back again without his father beside him. He wasn’t supposed to be here. Should he go back? He backpedaled a couple of steps before returning to the chain rope fence. But Dad told him to stay here. Izuku nervously hummed as his feet danced on the concrete in indecision until his eyes widened. The top of a small, blond head was...peeking over the curve of the rocks.

Izuku froze. Was that the owner of the fancy house? He didn’t see anyone enter the water, so were they there the entire time? They must have heard him and his father talking just a couple minutes ago. Should he say something? They haven’t said anything, so maybe it was okay. Izuku bit his lip, his hand tightening around the chain links.

“Um, excuse me?” Izuku asked in a small voice. He waited a dozen or so seconds, but there was no response, so he tried again. “I-Is it okay that I’m here? Um, if not, I will leave right now!” Izuku said a little louder this time and this time the tuft of hair shuffled but stayed surprisingly balanced in the rougher waves even as the wind picked up.

“H-HEY!” Izuku gathered the nerve to yell and the moment he did, a huge wave crashed into the rock and when it receded, they were gone. Izuku’s heart skipped a beat. Did they just go under? Swept away by a rogue wave? Izuku stood on his tiptoes to watch the water, waiting, hoping they would resurface. Minutes passed and they didn’t come back to the surface. Izuku looked around frantically, hoping his father was back by now. He would know what to do. The hair on the back of his neck stood on end as his eyes flickered back to the ocean to see the dark, human-shaped shadow below the water. What would All Might do?

His hands shaking, he lifted the chain and ducked under it to step over to the other side. He looked down at the rocks, flat with many footholds to climb closer to the water. “D-Don’t worry. I-I’m coming to help!” he yelled, hoping whoever it was could still hear him. The rocks were wet, covered in algae, and as he descended, more salty spray hit his face with each new wave causing his pace to be slow.

“A-Almost there,” he said when he got down to the rock just above where he saw the blond hair. Another wave crashed just below him. He fearfully looked around the deep blue water, hoping to catch sight of the shadow again.

“There!” Izuku shouted as he caught sight of dark shape again. “D-Don’t worry, I’m…” He couldn’t finish his hero’s catchphrase as shimmering, inky black scales broke the surface. And then the next moment, he was slammed into the rocks by a powerful wave.

Pain erupted from the back of his head and he saw stars. As the cold ocean swallowed him in its grasp, he felt the wound sting as the salt worked its way inside. He couldn’t see. He couldn’t breathe. He had to get to the surface. He kicked his legs and breached the water, gasping for air. Panting heavily and waving his limbs under him to try and stay afloat, e tried to touch the back of his head. He blinked the stars from his vision only to realize he was no longer close to the rocks. The realization came to him just as another wave slammed into him, drawing him under again.

He was spun and flung around, but by some miracle he managed to surface again, spitting up a mouthful of water. He didn’t know where the other person went, but he had to get back to the pier now. Otherwise, he would be swept out to sea at this rate, and he wouldn’t be able to help either of them. The thought of being stranded in the middle of nowhere, surrounded by nothing but waves and creatures with sharp teeth, never to be found, never to see his mom again… he whimpered. But he angled his little body towards the rocks and frog stroked with all the force his short little limbs could manage. Another wave. This one took him deeper, and water was forced up his nose. His vision burned and he wasn’t sure which way was up, but he found his way, breaching the water’s surface once again.

“H-Help!” he screeched. “Daddy! HELP!” He was so far away now, he wasn’t sure he could get back. “DADDY PLEASE COME B-” Another wave crashed into him and he was being dragged under by ocean’s cold hold. He was towed deeper, farther away from the pier by the second. He fought against the current to get to the shore, but it was relentless.

Izuku's lungs started to burn. His ears hurt as he was pulled deeper. He was getting light headed and the corners of his vision started to fade into black spots. His body recoiled for air but there wasn’t any. He fought and fought and kept fighting, but he was getting weaker by the second.

His limbs felt like lead pipes. His eyes made a last ditch effort to look around, only to see...the sun rippling over the surface? This was the last thing he was going to see? It was foolish of him to think a useless waste of space could help anyone. No one wanted to be around him. Even his dad could only stand a single week out of the year and his mom stays because she is too kind for this world. As his eyes started to drift close, he saw a shadow cross the corner of his vision until it completely eclipsed the sun and he was met with beautiful, scarlet eyes.

He was fixated by this dream with what must have been his last moments on this planet. The only reason he knew he was still alive was because of the pain in his lungs and the back of his head. Long, blond lashes framed the sharp pools of red as they looked at him quizzically, judging him. An angel, maybe? Izuku had never seen a human quite like this being, hovering so elegantly above him. He was transfixed as they grew closer and then… he felt something incredibly soft pressed against his lips. Whatever it was coaxed his lips open without letting any more water in, creating a seal between the two. It was like the kisses he sees couples have, but it was a lot saltier than he imagined it being. Something pinched his nose closed, and then he felt the air being forcefully pushed into his body.

Izuku’s eyes widen as he realized what was happening. Fresh oxygen was being supplied to his brain. Someone was saving him. His eyes tried to focus in on the person above him. Their eyebrow raised almost mockingly as they pulled away. Izuku gasped. Bubbles of his essential air escaped his mouth.

The first thing he noticed was the small, dark scales on their cheekbones that led up to fins where their ears should be. The fins spread out and twitched, stretching thin membranes between sharp, bony spines. As his eyes traveled down, he saw an adolescent body. Though they were more athletic than Izuku, they could have very easily been the same age. The very human torso, however, transitioned not into two separate limbs, but a long, scaled tail with two fins erupting from their hips. As they swayed effortlessly in the current, the sun revealed the rims of dark orange creating the illusion of tiny explosions on each small scale. Their tail was large like a fan, once again with the spines that stretched beyond the translucent membrane that looked like it would hurt if he was poked with them.

A mermaid. A merman? Merperson? Izuku actually wasn’t sure what this fascinating being floating in front of him was, but that didn’t really matter. His green eyes fluttered back to his red ones. The mer smirked arrogantly, showing off some very scary pointy teeth and suddenly flared out all their fins at once, causing Izuku to gulp, only barely holding his breath this time. They seemed to laugh as bubbles escape their nose and their short blond hair waved around with the movement.

Izuku felt light headed, from lack of air, blood loss, or both. This couldn’t be happening, could it? He rubbed his eyes. When he looked back up to where the mer was, nothing was there but empty water.

Izuku’s head swiveled around. Did he really just image all of that?! Moments later, he felt arms, small but strong wrap around his chest from behind. Izuku yelped, bubbles fleeing to the surface. His lungs started to burn again and in the next instant, he was being ferried away.





Izuku’s eyes shot open, the image of his father and mother spun above him. W-what was going on?

“OH IZUKU, BABY!” Mom was crying as she hugged him. “Oh thank god, you’re okay.” She started kissing him all over as Dad sighed in relief.

Izuku felt sand under his back, heard the sound of waves splashing on the beach, the cliff face behind him and slowly, he was able to remember what happened. It was fragmented, furry memories. He saw someone in the water and in his attempts to help them got swept away with the current. He was drowning, losing all hope and then he was saved… saved by a mermaid giving him a very salty, first kiss.




Chapter Text

Izuku sunk into the seat of his old car as it eased its way down the swaying road. The reliable Nokio sedan from the year he was born was like a fish out of water in this quiet neighborhood. Its extravagant beachside properties, two and sometimes three-storied abodes had large sun windows, decks, and of course, massive lawns with unicorns, dragons and other fanciful topiaries creatures duking it out. And between the vast ranges from one house to the next, Izuku had an excellent view of the coastline. Despite his attempt to keep his eyes focused on the road, he couldn’t help but glance over to the waiting ocean.

The waves lazily crashed against the sandy shores; the sun rippled in the frothy peaks. Docks jut out into the water’s reach as boats passed by without a care in the world. His hands were sweaty as he gripped the steering wheel tighter; his heart was pounding in his chest.

It wasn’t just his car that was out of place here. 

“In one hundred and fifty meters, slight right to stay on Dagobah Park Lane,” the robotic voice of his phone’s GPS stated.

Izuku forced fully brought his attention back to the road. “Thanks, Karen,” he mumbled as hovered his foot over the break to make the turn.

This would be good for him. He needed this… He wanted this.

Izuku bit his lip as his eyes wandered over to the superficially satisfying whitecaps. The number of houses he passed dwindled.


Izuku jumped at the phone’s loud ring through his car’s speakers. His eyes darted down to read the name, even though he could have guessed who it was.

“Hi, Mom,” he said after using his thumb to press the answer call button on the steering wheel.

“Hello Izuku, this is your mother speaking.”

Izuku rolled his eyes. “I know, that’s why I said ‘ Hi, Mom .’ Why do you insist on saying that every time you call me?”

“I thought you said you’ll call when you get there. You’re there, right?” Mom asked as she completely ignored his question because she knew he knew the answer. She was old fashioned and from a time before the magics of caller ID.

“I hit a bit of traffic getting out of the city, but I’m almost there. There is nothing to worry about.” Izuku passed a grounds worker on a riding lawn mower trimming the expanse of green honestly too big to be done any other way. The houses here have slowly picked out a different theme from the Boosie culture on the previous road. It was still ritties, but a much more tamed version of it with a Mediterranean/Spanish themed homes. 

“Are you sure? We could come—”

“Mom, I’m twenty-one years old. I’m not a little kid anymore. Having you and Dad here would be counterproductive.”

“I know, honey, but you’re so far away and—”

“It’s only a couple hours, assuming a cabbage truck doesn’t turn over and toss a couple of thousand green heads into the right of way.” The road steadily started to slope up as it trailed its way into an encroaching cliff side.

And we can’t just be there to help you right away if something comes up or happens. Do you have your medication?”

“Mom, please. You know I have it, you helped me pack.” Izuku took a deep breath. “We’ve talked about all of this already. I need some time to find myself and figure out what I want to do with my life. I’m not that far away, I have a couple of part-time interviews, I’ll be fine. Everything is going to be okay.”

The line was silent.

“Mom?” Izuku asked, worried that his call was cut off. 

“I’m still here, honey… Please forgive a mother for worrying.”

“Mom, I—”

“Your destination is on the right.”

“It seems like you’re there. Call me when you finish unpacking?”

“Of course.”

“I love you, Izuku.”

“I love you too.”



Izuku clicked the button to hang up as he pulled into a long driveway up to an affluent house on the cliffside. As he brought the car to a stop, he peered through the windshield at the place he would be staying for the next year.

It looked exactly as he remembered it from twelve years ago. He never expected he would ever live in a place like this back then. Its low-pitched red, scalloped roofs hung over the white stucco walls. Arched windows with fanned grilles overlooked modest, but impressive terraces on one side and the ocean on the other. It was the only house in the area and all the land surrounding it was owned by his father… well, stepfather. Toshinori Yagi, or as most people knew him by, All Might the former TV star and environmentalist icon. Even after nearly nine years, that fact still amazed him.

As All Might, he used to go around the world, seeing different cultures and exotic ecosystems in order to make an educational TV show for children. Unfortunately, during one of those trips, he was injured… badly. While he tried to make light of it now, he was dead on the table for nearly five minutes before they were able to revive him. His stomach was shredded and a good chunk of his liver and intestines went with it.

The day it happened, news stations were prematurely saying the star had died. Izuku was a wreck. First, his parents got a divorce, and then his hero “died”. He cried all through the night and into the next day until the story was retracted and explained  All Might had survived his injuries but was just in intensive care. A major medical miracle and a testament to the strong will he possessed. He was eventually transferred back to his home city for his physical therapy where his mother worked as a nurse and well, the rest was history.

The TV star had to hang up his costume after the whole ordeal. His body had weakened severely, and he could no longer keep up with any kind of exhaustive schedule. But he was still well-known and well-loved by the public to this day from reruns and his occasional public appearance, still championing the change in the way we interact with the environment and our cohabiters of this planet. It would be easy to assume that having such a man as your adoptive father would make you pretty popular at school.

It didn’t. 

He was lucky to make as good of friends as he did during high school. Iida, Uraraka and himself became a bit of a social outcast, but that honestly didn’t matter to him. They always had each other’s back through those awkward years of teenage hormones and crushes. He and Uraraka definitely didn’t work a couple. 

He was happy. 

It all went downhill when they were accepted to different colleges halfway across the country from one another. They still talking on social media, but it was never the same. They didn’t get to see each other other than during long breaks. 

Izuku tried to make friends in college. For a while, he thought Todoroki would be that friend he needed, and for a while, they did everything together. They even tried something that would make his mother blush. But they drifted apart, just the same as Uraraka and Iida when he got an internship at his father's company.

As the second year of college continued, Izuku’s slowly mounting dread started to overtake him. He was in his second year and he was still an undecided major. He knew he should have picked one by now because, at this point, he was just flushing All Might’s money down the toilet. He could be doing so much with that money, and here he was wasting it!

But he was indecisive. He stalled. He was trapped, unknowing what to do, what path to choose. How could people expect someone who was barely an adult to choose what they wanted to do for the rest of their life? What if he picked wrong and ended up somewhere he hates? He didn’t want to wake up in his forties realizing he wasted the best years of his life just for a stupid paycheck.

He was drowning.

Izuku took a stiff breath of the muggy air trapped within the car, his hand hovering over the handle before he opened the door. The tang of the sea air wrinkled his nose, causing him to sneeze. He took a couple of nervous steps towards the house but stopped as his eyes wandered to the side, down a small path to a small, secluded shore with a pier jutting out into the water. It was strange standing here looking down to where he stood a lifetime ago. The same place he fell into those cruel and unforgiving waves. The day his mother finally had enough and declared she was getting a divorce. And, of course, the day he was saved by a mermaid.

He was saved by a myth, a children's fairytale. Of course, no one believed the ramblings of a nine-year-old who just went through a traumatic experience. What he saw wasn't real. Mermaids weren't real. What he saw… what he felt… it was all a construct of his oxygen-deprived mind just before losing consciousness. The current brought him back to his frantic mother onshore, not a fantasy. 


Izuku closed his eyes as he let his lips part. The damp, salty air pressed against his lips. He could still see the red eyes burning in cold water. Sharp black scales, so jealous of the sun they took a part of it and made it their own. Soft blond hair that should be impossible in the salty waves. The ghost of his first kiss… no matter how many times he told himself it didn't happen… it was just too vivid to be something born from his mind.

Only one person didn’t outright scoff at the notion of a mermaid saving him and that was All Might. 

“Well, I guess it’s not out of the realm of possibilities; humans have only explored around five percent of our oceans, after all. If these creatures were intelligent enough to avoid human contact and have a method of disposing of their deceased so we couldn’t find remains, then maybe?” 

Izuku knew, even then, it was just an open-ended statement to humor him, but it meant the world to him. He would be lying if he said he didn’t spend the rest of that night speculating how a mermaid society could possibly function. 

How intelligent were they? Between the understanding mirth in its eyes and the knowledge not only that he needed air but how to transfer it underwater, Izuku would suspect very. Were they social creatures? Did they live in groups—pods? Or were they solitary? Could they communicate with one another vocally? If so, how? Clicking like a dolphin perhaps? If they did something with their dead (assuming they don’t consume their deceased), could they have some kind of concept of death and their own mortality? Could they have organized religions and governments with constitutions they were meant to follow? Was one of them not to make contact with humans? 

Why did that mermaid save his life that day?

Izuku opened his eyes and took another deep breath while watching the tide sparkle in the twilight. It wasn't like he was ever going to know the answers to any of those questions, he thought, tightening his fist. He turned back to the car to start unpacking.


Izuku stared blankly at the ceiling. No matter what he did, his mind didn’t want to rest and no matter how he turned, he didn’t feel comfortable. Sighing, he turned over again to grab his phone. The bright light burned his eyes. It took him a moment to readjust and read the time, 3:09 AM. 

“I guess it’s late enough for an early morning run,” he mumbled to himself as he righted himself on the side of his bed. The choice to sleep in what was his room during previous summers here, since it just felt wrong to sleep in the master bedroom… even if that big fluffy bed was calling for him. But he didn’t really need much: a bed, a desk, internet connection, a power outlet, and a connected bathroom was a nice touch. While simple, the room was more than he even needed. After changing into his running clothes in the light of his phone, he carefully started making his way through the house. 

While the mediterranean aesthetic continued to the architecture of the interior with stylized arches and an enclosed courtyard. The only place that jutted out with a more modern flare was the room housing the indoor pool. It was currently drained, (apparently, there had been some major malfunction with the filter). All Might told him to expect the repair guys in the next couple days, but he wasn't holding his breath over it.  

The only reprieve from this extravagance came from the same, simple furniture choices made by All Might that reminded him of home. But even with the familiarity, it had been years since the last time anyone had actually lived here. Nonetheless, the smell of cleaning supplies and lack of dust told him that a cleaning crew was here recently to prepare for his arrival.

As he passed a bookshelf packed with “How To Parenting” books, Izuku couldn’t help but smile. All Might was a good father, well, at least a better one than his biological one. He was always there for him. He was clumsy at times and didn’t give the clearest advice, but it was clear he cared for Izuku as if he were his own flesh and blood. He always listened to him and all his problems, no matter how silly they might have seemed, and tried to find healthy solutions. 

He tried his best to help with Izuku’s anxiety, had him start doing morning runs and some strength training. He was still small (even to this day), but he bulked up enough that he didn’t look like he could possibly blow away in the wind. And it definitely helped. Izuku couldn’t imagine nowadays going without that release, but it didn’t magically solve all his problems.

He stopped at the fridge to grab himself a water bottle and groaned. It was packed to the brim with food. A note on the door caught his eye and a sigh escaped him, thinking about all the groceries he had just bought.

Sorry, I know you said you'd cover food expenses yourself, but Mom insisted on providing you with the basics.

Dad <3  

Izuku frowned, shaking his head. Looking at it again now, there was no way he alone was going to be able to eat it all before it went bad. But his mother had been codding him for years now and he wasn’t exactly stopping her. He knew she had her reasons and was only trying to help him, but it was only making him feel worse about himself. She didn’t like this plan he and All Might came up with and only agreed after months of bargain and compromises.

Izuku could take a year off from school, live by himself at All Might’s summer home on the coast of Dagobah Beach. The rent and utilities were paid for by them, but Izuku (on his own request) would cover his own food and personal expenses. He already felt like a spoiled rich kid having this opportunity in the first place. Getting a part-time job would get him out of the house and feeling better about all of this. 

This was his chance to breathe. A chance to find himself and explore what he wanted without the pressure of school and home life. A chance, so simple, but it was something he so desperately needed to find his way out of the dark. 

Izuku opened the door into the crisp, early morning air and looked out. It was darker than he expected, only the smallest of slivers of the waning moon left in a cloudy sky. He had to keep sure not to trip over anything, he thought as he took the path down towards the beach. The sand would provide some excellent resistance compared to his normal route and hopefully tire himself out more quickly. Once down on the sand, he did some quick stretches while looking out to the ocean. It was so peaceful. 

He quickly realized the small amount of surrounded beach would be too small to suffice, so he passed through the natural rock arch and into the long stretch of public beach. Summer was just around the corner, but it was obviously too early for people to start arriving, so he had the entire length to himself. 

Izuku could feel himself loosening up at the familiar burn in his legs. Back home, even this early in the morning, there were always people around. It was just a fact of living in a crowded city, someone else was always awake. But here? It was just him, the sand, the surprisingly pleasant sounds of the ocean, and that bright, searchlight swerving off the coast in the distance. 

A boat? Out at this time with such a bright light, could it be the coast guard? 

Izuku slowed his pace to keep an eye on the boat as it made its way down the beach, towards where he was running. It wasn’t terribly far offshore, but Izuku could barely hear the motor as it passed him the first time, too busy combing the area with its light pointed towards the ocean’s floor. 

Was it looking for someone? He wondered as he came to a stop to catch his breath before turning around to go back home. Maybe someone fell in and they were looking for them, but he would think there would be more of them out there if that was the case. Looking as the boat passed again, Izuku got out his phone out and started searching the internet for any news if anyone fell off a boat or something. He was also trying not to think about the fact if they were looking at this late, and so close to shore, they were likely looking for a body.

After a few minutes of fruitless searching, Izuku frowned, putting away his phone only to be immediately stunned by the bright light suddenly shone on him. How did the boat get so close without him hearing it?

“A little early for a morning run?” A man yelled through a megaphone.

“Yeah, what are you doing here?” Another voice chimed in. 

Izuku winced, trying to block out some of the light with his extended hands. He could barely make out the boat and that there were three figures standing aboard it. The boat was a good deal smaller than what he originally thought and from the outlines, it appeared to be a private fishing boat, rigid with nets, a spotlight, and a… mounted harpoon gun aimed directly at him. 

His heart started pounding in his chest as all the warmth left his body. 

“Don’t tell your mother I told you this…” 

He wanted to scream, but nothing passed his lips. His mind was racing. Could he outrun a harpoon gun? They were unsettlingly close to shore even for a smaller boat, but they were still pretty far away… surely that thing couldn’t be accurate at this range. He was fast, second only to Iida on his varsity high school track team, but he wasn’t sure how well that speed translated on the sand.

All thoughts of running died in the next moment as a fourth person walked into shadowy sight branding something in their hand. A gun

“You’ve haven’t seen anything… fishy have you?” He could just make out the shadow of a vertical line straight across the megaphone guy’s forehead. 

“Why would you say that, idiot. You’re going to make him suspicious something’s wrong. Which there’s not.” The megaphone didn’t switch hands… wait, has it been only one person talking up until this point?

Izuku shook his head wildly to ensure they could see it. He felt like he was about to pass out. He was going to die here, he had no doubt they were going to kill him. He’ll never get a chance to find himself because his life is ending right here. I’m sorry mom I was so rude in our last call together. I’m sorry All Might, you tried to be a good father, but I was just a—


“Now run home now and keep it that way,” the same person said in a deeper, almost scowled tone. 

Izuku tilted his head to the side, tears threatening to fall from his eyes as he blinks in confusion. They were just going to… let him go? 

“Wait,” as the fourth shadow leaned over to the first and spoke into the megaphone. 

This beach had a blood vendetta against him. 

“Don’t want you calling anybody anytime soon, now don’t we? Throw your phone into the water,” he said as he raised his arm towards him. 

“You heard the boss, chuck it,” the original person said, stealing the megaphone back.

Izuku nodded, his eyes fixated on the metal glint of the barrel pointed at him and without a moment hesitation, he obeyed. He threw it as far as he could. When he heard the pitiful splash, he watched as the armed hand was lowered. 

“Nice throw!” He was actually giving him a thumbs up. No way this is real life, right? He had to be dreaming? 

“Now scam kid before we change our mind.”


Izuku didn’t even acknowledge him as he dashed as fast as his legs could take him. He didn’t look back, he just ran as he heard a chuckle of laughter from the ship. The light didn’t follow him and it was still too dark to see well without it, so he thought it would be best to just go straight home without fear of them following him. 

As he passed the large rock formation into the private beach, he finally slowed down enough to let his mind catch up to the rest of his body while still moving towards the path to the house. That happened. That really happened. He had no doubt in his mind they were poachers. Dangerous poachers at that! And he led them straight to him from the light of his phone. He could kick himself. But that didn’t matter, he had to get in the house, find some way to contact the authorities and—

Izuku lost his train of thought as he saw something move out of the corner of his eye. He was worried it was the poachers again, but what he saw gave him pause. It was laying half out of the surf, large, dark, and definitely wasn’t there when he left originally. He watched as the mass raised before releasing in a struggling collapse. Something long and metal was sticking out of it unnaturally. His mind put two and two together. Whatever this was, was what the poachers shot and currently looking for. 

He had to help. 

Izuku, despite his nerves, screaming to run into the house and lock the doors, and his mind asking, how exactly is he going to help, he started towards the mass. His approach was slow, trying not to scare the creature further as he watched it. It was long, easy over two meters. Its tail flipped directly up, glinting in the subtle moonlight before splashing once again in the water in frustration. 

Why was his heart racing?

He heard the troubled breathing as it tried desperately to move followed by a pained cry that nearly tore Izuku’s heart in two. 

Izuku wanted to reassure it. The words fall from his lips before he could stop them. “I-It’s okay, I am here to help you.”

Fins flared and panic scarlet eyes locked onto his green ones. And Izuku couldn't help the gasp that left him.

He knew those eyes.

Chapter Text

Baby Mermaid Katsuki

[DarkMachi's Twitter]


  “It’s you…” Izuku whispered, his eyes wide to trace every inch of the dark face. He couldn’t make out details in the dim waning moonlight, but the feeling bubbling in his gut told him that this was the same mer that saved him all those years ago. Just the shape of her face, while more angular and sharp, still held the distributing features he remembered, most importantly of all those burning eyes seeming to be lit with fire. 

He couldn’t stop the smile. It was like meeting up with an old friend, but better. He pinched himself on his cheek, and then pinched himself a second time even harder, just for good measure. It hurt, he would sure he was going to have a mark from it for the next couple hours… this was really happening. The bubble of happiness tripled in this stomach before erupting from his mouth in an ecstatic, if not slightly crazed, laughter. “You ARE real!”

The mer recoiled with a hiss at the sudden cry. The glint of her pearly-white teeth glinted off the moonlight and her tail fins seemed to bristle in warning before flinching. Right. Injured.

Izuku, reminding himself of the actual severity of the situation apologized as he ran a hand through his hair to try and calm down. Get it together . “It’s not every day you get threatened at gunpoint one minute only to find the mermaid that saved you as a child in the next,” he mumbled more to himself than the mermaid.

When he looked back over to her, her almond-shaped eyes were narrowed, her fins trembled from their outstretched state. 

The waves lap onto the shore as the tide leisurely came in, spraying his face with its chilly caress. He honestly had so many questions for her, but his mind echoed the words that he knew were true… there was a time and a place for everything but not now.

The poachers were hunting his mermaid. 

His mind started to piece together the turn of events that brought her to shore. His eyes trailed up the frayed ends of a rope as they danced across the surface of the water up to where it was tied off at the barbaric harpoon that pierced into the flesh of her strong tail. A finely meshed net wrapped tightly about a majority of her torso, arms, and the harpoon in a matter he knew it came after. The net restrained her arms, only a bit of her shoulder and hands were free from its hold. 

It was cutting into the skin, he realized, observing how the skin seemed to glisten with a darker liquid, dripping down onto the sand below where the net lacerates. The feisty mermaid only had her harpooned tail to get away from them… she’s something else. 

Izuku turn in the direction of the other beach. The last he saw them; they were going the other direction, but it could be only a matter of time before they doubt back this way. Just because they were on a private part of the beach doesn’t mean they were safe. He needed to hurry.

He turned back to lock with the ruby gems and took one nervous step forward. “W-We have to get you out of here,” he tried to say calmly, but they ended up coming out as a jumble of words instead. He took another two steps forward. “My house is just up the cliff here,” he said, pointing to the dark home. “I-I know it’s not ideal, but I can bring you there to hide from the poachers hunting you.” His mind was racing trying to figure out the logistics of getting the mermaid into his house, but because of the lack of time, they had very few options. 

“D-Do you need water to breathe?” He looked at the mer, while her breathing was heavy (from the nets or the method, he wasn’t sure), but she WAS breathing. Unless her gills were on the end of her tail, she could at least for a time breath from the air, it seemed. “O-Or do you need to be partly submerged? O-Or maybe it's drying out we have to worry about… But we don’t have time for this, can you hold out a couple of minutes without water while getting you there? I-It’s not ideal, but I need to c-carry you,” Izuku stopped his forward momentum as heat flushed his cheeks. It wasn’t ideal, but it was better than dragging the poor creature. He would just have to be careful not to touch the harpoon.

The mermaid’s head was slightly tilted to the side, a contemplative frown in place. Her fins have lowered, somewhat at least, and her “ears” flickered at the repeated sound of his voice. 

He waited a moment, but she didn’t respond. 

“I’ll take that as a yes?” He questioned, once again not getting a response other that a flip of her tail. Crap. Here goes nothing, he thought before shuffling forward, minding his footing on the rocks, heart in his throat. He reached out.

“I-I’ll try to be gen—”

The growl was the only warning before sharp teeth snapped shut over the ghost of his hand. With the rescued limb to his chest, Izuku looked owlishly at the mermaid. 

She let out a chorus of (surprisingly) deep, unintelligible noises. It was both completely foreign, with clicks and trills he could never hope to duplicate, but also not just random noises of a distressed animal. There was a pattern to it, structure. A language. A language sang in a manner, unlike anything he’s ever heard. 

He watched the tension in her jaw as she ground her teeth as him, and he came to two conclusions. One: mermaids did, in fact, have their own language--probably more than one--and two: he was lucky he still had his fingers.

The moisture in the air seemed to double in density, pinning him to his stop as the words escape his lips. “You don’t understand me, do you?”

The mermaid hissed at his words, and the calm wariness she excluded before was completely erased in an instant. Her brows were heavy on her face, lips pulled back into a sneer that showed off razor-sharp teeth, and Izuku didn’t doubt that if she could have, she would have burned him alive with those volcanic eyes of hers. Said eyes didn’t waver from him as she tried to writhe, trying to put some space between them. 

“Wait. Don’t--!”

Unfortunately, it only served to tighten the net. Her teeth grounded together to try and hide the pain; a breathless rumble escaped her teeth. 

Despite her antagonism, the moment he Izuku saw the scarlet stained rope dig into her skin and even more blood escape her wounds, he was already in action. 

“Crap. Just--Please. Don’t try to move,” he said, once again throwing himself into the danger zone to stop her from moving further. 

She launched at him again, in spite of her bindings. She was fast, and this time he didn’t react fast enough.

“Son of a—” Izuku hissed, self-censoring himself. He held his pounding hand closed. Two clean cuts started to ooze crimson on his right hand’s ring and pinky finger. They were luckily pretty shallow, only a couple millimeters deep, but damn it if they didn’t burn. Out of habit, he stuck the sides of the digits into his mouth to lick off the blood. He looked back at the mer.

She was humming something with a small, almost boasting smirk on her face. She made a bit of a show as she licked teeth of the few drops of his blood that still hung from them.  Her eyes challenged him. He got the message. Try that again and see what happens.

Izuku frowned, tears pricked the corner of his eyes as he looked into hers. But he wasn’t mad at her. He took his hand out of his mouth and sighed. “I-I’m sorry. I’m scaring you, aren’t I? You don’t know I’m trying to help you. To you, I’m just another human,” his voice wavers, and his lips twitch in irony. You don’t recognize me . “For all you know, I’m working with those evil people that are hunting you.” Izuku shook his head. “You’re badly hurt, can’t understand a word I’m saying, and you’re out of your element. I-I don’t blame you for hurting me,” he gave her a shaky smile. 

The mermaid's grin actually faltered as he spoke. Her fins twitched, and her eyes narrowed in uncertainty. 

Izuku blinked. Oh. While it’s clear she can’t understand the words, maybe there was still a way he could communicate his meaning. “I wish I was better at charades,” he whispered to himself before he slapped the sides of his face to psych himself up. 

The mer jumped at the sudden action. 

He met the mer’s glaze to ensure he had her attention. “I,” he said firmly as he pointed directly at himself with both arms. “No,” he shook his head only to realize, she might not understand what shaking and nodding of the head means. He paused for a second as he tried to think up a change in strategy. He pointed at the harpoon, keeping sure her eyes followed the motion, and then out towards the other beach where he knew the poachers were. He then made the most over-exaggerated, disgusted face he’s ever pulled imaging the time he walked in on All Might shaving Mom’s legs in the bathtub (the door wasn’t locked parents!). “Them.” 

It was a stretch, but the mermaid did seem to use facial expressions similar to those of humans. He just hoped this will get his meaning across. 

She raised an eyebrow, her head once again slightly tilted to the side like a puppy. 

At least she seemed to be paying attention...He went through the motions again. He pointed to himself, “I.” He grimaced, this time thinking about the one time he stepped on a week old, half-eaten sandwich just laying on Uraraka’s floor, “No.” He pointed to the harpoon, and then out towards the dark water, “The—”

Izuku’s eyes grew to the size of dinner plates as the light pierced through the rocky arch and reflected on the surface of the water. 

They were out of time.

Izuku gulped, but he found his mouth was completely dry. He knew, the instant they come around that corner, he wasn’t going to get lucky a second time. Especially not if he’s sitting here, right next to their hunting trophy. He was shaking, as his self-preservation instinct was telling him to run and don’t look back. He tried, he really tried to help her. But… He bit back his fearful tears and spun around to look back at the mermaid.

Her eyes were blown wide as she was transfixed on the dancing lights on the water. She abandoned the mask and fear freely dripped from her face. Her eyes jolted to his and a tidal wave of emotions hit him all at once. She was just as scared as he was. If he left her here… she was going to die.

He took a deep breath and braced himself, not dropping the eye contact. He had no more time and no more options. Even if she tore into him, he just needed to get her out and hope the damage didn’t kill him.

Her mouth quivered before clenching. Her eyes burnt into his soul. She looked back to the water, the light growing closer by the second, and then back to him. And then she closed her eyes.

He started reaching out again, only to stop.

Her lips parted, and she mumbled something. It was softer than all of her previous “words”. Her eyes slowly opened and looked at him. Her eyes were steeled with newfound determination and credence. Her body un-tensed and other than her troubled breathing, she was still. 

He clenched his teeth, looking from his outstretched hand then to her.

She repeats the same sound again, a little louder, and possibly a bit annoyed.

“O-Okay,” Izuku said, then went for it. 

He maneuvered his hand between the middle of her chest and the sand. While it was completely covered in net—thank God— Izuku noticed its board nature and relative flatness, but he contributed to how tightly the net was bond around her. He didn’t stop moving to check for the mermaid’s approval, but he thought the lack of aggression counted as an O.K. He repeated the action near her waist.

This time, her face tightened in pain. The harpoon was stabbed into the upper portion of her tail where, if she were human, a thigh would be. He had no clue how deep it was, or how much damage was done by it, but moving her so close to it caused her pain. “S-Sorry, but you’re going to have to put up with it for just a little bit,” Izuku whispered to half-open eyes.

It only took a couple more seconds, but it felt like hours, to get a grip he was satisfied with. “Lift with your legs and not your back,” he muttered as he lifted just as All Might taught him. It was easier than he thought it would be. She wasn’t weightless, but she was a lot closer to picking up 156 cm tall Uraraka instead of 195 cm tall Todoroki which she was closer to in length.

The mermaid tensed in his hold, let out an indignant hiss from between her teeth.

“I’m sorry,” he said again. He looked back toward the oceanic arch and did a double-take. The boat was already lazily making its way into the personal beach’s area. Cold sweat dripped down Izuku’s back as the light swiveled around, combing the water for their prey. 

The mermaid flipped her tail at him.

He sprinted.

There were no shouts, no alarms set off, no gunshots, and despite the awkwardness of carrying what Izuku kept realizing was a fully grown mermaid whilst racing up the beach, they made it safely to the path leading to the house.

The path was steep and narrow. It only allowed for single filed ascent and descent. Izuku looked over to the tail, hanging limply off the side of his arm, knowing there was no way to do this easily. He turned to the side and started again. It was a difficult trudge, his forehead was glancing with sweat by the time he got to the top, but he didn’t stop even for a second to look back. Not when they were so close to being home free.

Sliding open the door was likely the hardest part for the mermaid. While she’d grunted and bore the pain as he bounced up the cliffside, he had to juggle her around in his tired hands just to get the door open. It was so bad, she leaned over and gave him a nice “little” warning bite on his side. It wasn’t deep, not even as deep as the ones on his fingers, but she used her entire row of pointy teeth to make her point.

As he closed the door on the other side and locked it for good measure, he finally allowed himself to look back. The boat was now in the middle of the harbor. Their spotlight moves across the water, up towards the beach… right where they were but minutes before and stays there. Something warm drips down his leg, and a cold realization hit him.

The blood.

There was one spot on the beach just soaked with the mermaid’s blood. Then, no doubt, there was a suspicious blood trail leading them up the cliffside right to his home. How did he not take that into account? While his mind was busy in its attempts to reason out the logistics of stuffing the mermaid into the back of the Nokio, the beam of light drifter down the beach before it just… moved on.

Izuku blinked in surprise as he watched the boat deliberately passes by and kept moving down the coastline. There was a moment of complete silence before he let out the breath he didn’t know he was holding. They did it. He did it. He saved her from the poachers.

He felt the mermaid in his hands shift as she too peeks out over the water just as they disappear from sight. She let out a vocal arrangement of sounds of triumph.

Nonetheless, Izuku chuckled as tears of pure relief started to flow freely. It would take him a couple more minutes and for the adrenaline ebbed his system making his arms and legs feel more like jelly than limbs for him to realize it wasn’t over yet. 

Now, he thought as he looked over his charge, stubbornly refusing to lose consciousness despite the loss of blood. Now, he had an aggressive mermaid to take care of. 

Chapter Text

Angry Boi



Izuku could feel the mermaid’s breath against his arm. Ragged. Weak. It was weaker than before. 

“Don’t worry, I’ll get you patched up and back into the water in no time,” he said in a reassuring voice, hoping his tone alone would be enough.

She let out a flat croon, a small rumble against his chest. She didn’t sound happy, but it was also a far call from being mad. Small victory. Her tail trembled sluggishly as he tried to maneuver it around the dim archway. In fact, all of her movements had become lethargic, and while it did make things easier for him, it was no doubt concerning. She’s probably lost a lot of blood by now, and he wasn’t sure how exactly being out of the water was affecting her.

As he made his way through the property, he considered his options. He had to hurry. The pool would have been an excellent place for this rescue, and he cursed the stupid pump. Of all the times to be broken… He would have to use the master’s bathtub. It’s the only place to put her that could marginally accommodate her size. He glanced at his charge, considering the tail, draped over his arm and nearly reaching his knees… Well, if All Might could fit in it, he reasoned, she should be able to as well.

By the time they made it past the master bedroom and through the bathroom doors, his arms were tingling with the effort of holding the drained mer. And it took his every effort to carefully lower her down on the floor. He took a deep breath in, blood rushing through his arms, properly filling them with oxygen again. He was panting heavily, but he didn’t give himself a moment to catch his breath. They were running out of time. 

He sprang to his feet, vision swirling, and he had to clench the wall for a moment to regain his composure. In the moment of confusion, it suddenly occurred to him that he hadn’t slept last night. Actually, he hadn’t slept well for the past complete nights if he was being honest with himself, which meant he was running on fumes and not much of anything else and after everything that just happened no wonder he was--were those spots he was seeing?

A sharp clicking brought him out of it, and he turned to see the dark outline of the mermaid. She had propped herself up as far as she could, and was...tilting her head towards him? He couldn’t see very well without the lights, but chose to interpret that as concern.

“Don’t worry, I’m fine.” He patted the wall to locate the switch. “I’m going to turn on the lights so we can have a good look at what we’re dealing with, okay?” He asked because it felt inconsiderate not to warn her first.

Her fins twitched again, and she grumbled something in frustration.

He expected some kind of reaction out of the mer as the room was all of a sudden bathed in a blinding, warmglow. He had no clue how much she understood about humans and their technology. Electricity was, afterall, not compatible with water, and he didn’t know if they used something to see in the dark or if they could see in the dark like a lot of deepwater sea creatures or whatnot. Either way, the reaction he got was definitively abrupt, if not impressive.

Fins snapped open in a display of color at both head and tail. Her head swiveled around the room with a hiss, and red eyes narrowed to slits as a cloudy thin membrane slid over them. Her body was tense and almost squirming in her bindings. A mixture of grated sounds, from low growls to high and clipped trills filled the room. (Mer-tongue, Izuku realized.) And as her vision finally adjusted, she seemed to identify the source of the light, glaring at the fixtures on the ceiling, and started to yell at them .

Izuku could only blink. He had a mermaid in his parents’ bathroom… yelling at the light bulbs.

He knew this wasn’t the time for this, but Izuku couldn’t help himself at the pure absurdity of the situation and a laugh tore from his throat. Leaned against the wall, he let himself slowly sink to the ground, sides clenching. It wasn’t that funny; he knew it wasn’t. But he couldn’t stop. Tears ran down his cheeks when he finally noticed the room was quiet, aside from his hysterical laughter. He slowly turned his head to face the mer.

Chin jutted outward, her glower was easy to read: You done yet?

But Izuku wasn’t paying attention to her clear annoyance as his heart was too busy skipping a beat.


In the light, he was finally getting a good look at her for the first time in years. Her prominent cheekbones, covered in dark and lustrous scales, perfectly framed her face. Even in this artificial light, they shone with tiny explosions of color. Her short, blonde hair started bushing out in every direction as her hair started to dry. It gave her a cute, tom-boyish look which went well with her athletic build; he wasn’t the only one that bulked up over the last decade, apparently. Despite the prominent musculature, she was still narrow--no, rather--streamlined. He had no doubt she could tear through the water as a bird took to the air. As the foreign, infuriated words hit his ears he noticed the glossiness of her scarlet lips. And only then did he notice the glossiness didn’t come from the wounds she left on him, but a gap in her sharp, pearly whites. She lost a tooth.

Izuku frowned, his eyes narrowed as they were drawn to blooms of crimson that dripped from her body, but most importantly, the net around her chest was smeared with more blood than the rest. He got on hands and knees and scooted closer. Just below her collar bone, the ends were frayed, not dissimilar to the manner in which the rope was severed. She had tried to chewy her way through the net, but something was off. The material of the net looked surprisingly thin. The mermaid should have had any trouble ripping through it like wet tissue paper. He crawled further forward.

The mer’s eyes narrowed and her lips twitch but didn’t make a noise. She merely watched as he reached for the odd, frayed ends of the curious material.

The second his finger made contact; he recoiled as something sharp stuck into his finger. What the... He squinted at the drop of blood that surfaced from his pointer finger. He looked closer at the net and only then noticed the metal. The outside of threads were fiber-based, but the inside was reinforced with metal. He frowned. A net deliberately made for a strong creature, a smart creature, and cut into its skin to keep them from breaking free.

The mer erupted in a pained chortle. Izuku looked up to meet her face, her lips pulled into a smug smirk despite the tension on her body. A mirror of the mischievous face that has been living in his dreams since he was a child.

Izuku rolled his eyes to act annoyed but couldn’t completely hide his smile. He couldn’t with a heart fluttering like a hummingbird’s wings. “Hah, very funny. You know you could have warned me,” Izuku said looking only inches away from mirthful red eyes.

She was panting heavily, but she tilted her head toward the ceiling, or more specifically toward the lights before looking back to him.

It was a peculiar action and it took him a moment to piece together her impish behavior. Payback.

A cough racked through her, and as blood hit his leg, the severity of the situation seemed to once again settle over them. Another frown. Izuku had wasted precious time. 

He shuffled around the mer, aware that the mermaid’s eyes were always on him. He originally planned to cut it off her to limit the amount of movement she had to endure; this new revelation made things that much more difficult. It looked like a single long net, so once he found the end, it shouldn’t be too bad, he thought, only to pause when he finally got a good look at the ghastly wound created from the dark-metal projectile, feeling bile poke at his throat. 

The skin was dug up as the tip of one barb was already partly sticking out, only being held in place by the net. Blood caked on either side of the adjacent material and it had already started to dry even as more blood dripped out of the wound. It was worse than he thought. The net was one thing… how the hell was he supposed to treat a wound like this! He was in over his head. He had to call for help.

He patted his pocket only to groan. Think Izuku, your phone is now sleeping with the fishes. He shook his head. Maybe he could still grab his laptop and try to contact All Might that way, he thought, only to look toward the bedroom and out the window. It was still pitch blackout, it would be hours until his mom or dad would read it and by then it could be too late. Besides, how would they react to a message like:

Hey Mom and Dad, how ever do you treat a harpoon wound? No, I’m not the one that’s hurt. It’s actually a mermaid -- the same mermaid that saved me when I was a kid that I kept telling you was real, but you didn’t believe me -- that is hurt. She was attacked by poachers who also threatened me and had me throw my phone into the ocean. Please hurry, she is bleeding out onto your bathroom floor. Thanks! 

Izuku ran a hand down his face and sighed. They would think he was drunk… or high… or maybe both. His mom would still rush over here, but that wouldn’t be for hours at least. That meant, for now at least, he was on his own.

The mermaid’s head tilted further to the side and she let out an irritated warble. 

Izuku blinked. “That was out loud, wasn’t it?”

Her eyes narrowed, and she shuffled in place against her restraints, but not enough to hurt herself, before repeating the same pattern of sounds again. Even her voice seemed to be turning hoarse. But she seemed to be looking at him earnestly now, wiggling in place and glancing at her tangled torso before meeting his eyes again.

Izuku nodded, “Yes, of course.” Once the net was off her and she felt a bit more comfortable, he just had to get her into some water, and then he could go get his laptop. He knew the harpoon needed to come out, but he was also worried if he just willy-nilly tried to take it out. He didn’t know mermaid anatomy or physiology, and while for a human the wound would be roughly around the upper thighs, it could also be right next to something important for her, a vital artery or an organ. He doesn’t know what he would do if she really bled out right in front of him.

He easily found the end of her bindings wrapped around the mid-length of her tail, just a bit below where the harpoon pierced her. It was caught between a couple of her fins. He looked at her face, “I’m going to start now,” before he reached out and carefully started to work it off.

Her fins fluttered when he had to touch them, but when he looked back to her face, he could see she was fighting to stay conscious. Her eyes drooped closed for longer and longer periods of time, but she wouldn’t let herself pass out, almost getting angry with herself every time she shook her head.

As Izuku worked, he took a moment to realize that she had a… slipperiness to her skin and scales. It wasn’t slimy, per se, nor was it enough for him to think that if the net’s fiction wasn’t there, he wouldn’t have been able to hold her. It was just a thin transparent layer that surrounded her body. Hm.

With a bit of help from the mer, he was able to free a majority of her lower tail without any issues. She seemed pleased to be able to flex her fins freely now, but next came likely the hardest part. The net that surrounded the wound. He pulled a little bit on it, only for the Mer to hiss at him. It pulled on the dry blood and scales around the wound, not dissimilar to a band-aid. 

Izuku gulped and looked back from the task to the mermaid’s face. “This is going to hurt,” he tried to warn. He tugged on the net again and mirrored the wince the mermaid made. “Hurt,” he repeated clearly. 

Red eyes went between his face, the harpoon wound, and then the net before they turned to their starting location between slow blinks. And then she did something surprising. 

She nodded. 

It was slow, unsure before she laid her head on the ground on top of the bathmat.  

Izuku eyes were the size of dinner plates right now. Did she really just nod? “O-Okay?” Izuku said as he nodded back with a smile that grew on his face. “Okay!” The mere act of nodding opened up so much for them in terms of communication moving forward.

Izuku took a deep breath to steady shaking hands. “Rip off the band-aid. One, two, three !” He realized his mistake as soon as he did it. On three, he pulled back the net in one clean motion… or he tried to. The already clotting blood was ripped asunder and the blood started to flow freely once more. But bad only got worse, and the next few seconds seemed to happen in slow motion. 

The mermaid recoiled. Her powerful tail tensed up, and off the ground. But they were too close to the solid vanity counter. The end of the harpoon crashed into the underbelly of the granite; it didn’t give. It didn’t give . Izuku watched in horror as he was unable to help as the torque pushed the barbed head upward… through the fresh and scales. It ripped out a chunk of blooded flesh as the unforgiving metal clanked to the ground. But Izuku couldn’t hear it over the blood-curdling scream. 

He turned his head and threw up.


The sun had started to make its presence known, warming the sky in a deep orange when Izuku let out a huge yawn, leaning against the nearest wall for support. His bones might as well be made of lead for how heavy his limbs felt. He couldn’t remember a time he had ever been more physically and mentally drained than he was right then. He probably could have slept for the next week straight and still feel exhausted. He glanced into the mirror only to wince at his reflection; he looked like a horror movie villain, or perhaps an overzealous butcher that picked a fight with a shark.

The bathroom looked like a warzone from the not so graceful removal of the harpoon from the mer’s tail. There were scarlet specks flung to the far corners of the room from the agonizing whipping of a tail and like little rivers stains filled the cracks between the tiles. Formerly white towels laid crumpled to soak in the sink. A knocked over container of table salt lay near the tub. Shreds of the bathmat were scattered around the room with suspicious bite marks. A discarded bottle of disinfectant and tube of antibiotic cream sat precariously on the bathroom sink next to his failed attempts at using the gauzes. And then on the corner as far away from the rest as possible was his laptop, still opened to the search of how to treat a harpoon wound. He didn’t even want to think about how long this would take to clean up.

Izuku yawned again. But then again, does it really matter how bad he or the room looked? When his eyes opened again, they settled on the peaceful slumber in the saltwater bath; the feisty, blond mer man . If he had the energy, he would have kicked himself. He can’t believe how foolish he was for just assuming the mermaid was--well--a maid ! His cheeks were still warm from the embarrassment from that...revelation. He didn’t know how his mind could have just glossed over all the clues presented in front of him. Idiot.

After the struggle to clean and close the wound, he had finally seemed to get the bleeding under control with some strategically placed wet gauzes and wrappings. The mer had passed out sometime before between the blood loss and the shock, but not before a couple of frantic minutes of very physically and very clearly telling him that he wasn’t a very happy sea creature. Izuku honestly didn’t look too much better than the merman (if you discount the gaping hole of the harpoon wound) as he was littered with scratches from thrashing fins and the earlier bite wounds. The two species’ crimson paint became indistinguishable from each other as the masterpiece took shape.

He had only given himself a couple of minutes break after that before he’d returned to tackling the rest of the net. The other side of the harpoon wound had been already, much more carefully this time, removed and replaced with clean gauzes and the thin, metal-filled material laid loosely around the fins around his hips. It was harder to move around the flaccid body but after setting up the mer so he was leaning against the wall, it became a much smoother task.

At the time, his heart was pounding. He’d tried to tell himself as he got closer to unwrapping “her” chest, that this would be so “she” would be more comfortable. It wasn’t like he was going to take advantage of “her” being unconscious, no he wasn’t even going to look. That would be rude, disrespectful, and non-consensual. But his train of thought was interpreted as he started to notice “her” stomach was very toned with defined muscular and… oh wait, that’s totally a six-pack. He knew girls could have six-packs but… his mouth dried up as he quickly removed the last of the net from the mer’s body to see not breasts, but very toned abs. His face exploded with a blush rivaling the merman’s eye color...

Izuku was brought back to the present when the mer’s head tilted to the side and off the towel he’d popped up for him. The blond’s head hit the back of the tub, and he let out a low moan, the end of his tail twitching where it lolled out and over the other end of the tub. 

Despite his exhaustion, Izuku found the energy to pick himself up and walk over. “I know, it’s not very comfortable, even if you weren’t injured already,” he hummed quietly. His knees popped when he kneeled down beside the tub. “I’m sorry, it’s the best I have for now.”

Izuku’s fingers ghosted over the mer’s skin, noting how it seemed drier than before. He adjusted the towel before he guided the merman’s head back into place, hopefully a little more secure this time. He wasn’t sure if the mer could breathe underwater, he assumed he could, but he wasn’t going to try now by dunking his head under the pink-tinted water. Right now, he seemed to be doing well enough breathing from the air, so he was not going to chance it. 

He grabbed a nearby washcloth and submerged it into the water. Without wringing it, he placed it on the mer’s head before repeating the action with a larger, clean towel and putting it over his exposed tail. While breathing above water didn’t seem to be a problem, he could see how the transparent liquid that covered his scales started to dry out with time. 

He traced the rough scales on his cheeks with his fingers, once again struck by their shine and how they seemed to smooth out into the soft skin of his cheek...a sharp jawline...and soft pouting lips... He jerks back, falling onto the cold tiles of the floor. His heart was pounding and his face felt like it was burning as his actions dawned on him

What the hell am I doing.


Chapter Text

Angry Boi

[DarkMachi's Twitter]


Izuku jolted from his sleep with a crash. His face plastered against the floor, drool dripping from his mouth as his eyes bolted open. The only light came from the far window in the other room as the sun said its farewells and dipped from sight. The trance of sleep was still heavy in his head making both his body and mind numb. Was he in his parents’ bathroom? He stretched his legs only to hit against the hard plastic of his dark-screened laptop. Huh… what was he doing in his parent's bathroom with-- Red eyes. He was staring into red eyes.

Izuku rubbed his eyes and when he looked back, the merman was still there. He was lying belly down on the floor with him, his tail raised as water dripped to the floor, frozen like a child caught trying to steal cookies from the cookie jar. Oh.

“Um…” That's as far as Izuku got though before the mer bolted. 

His tail scrunched up behind him and his arms lunged forward towards the room’s only exit in the single, ungraceful flop. A spray of water hit Izuku in the face. 

The creature let out a pained groan as he landed. He attempted the same action again, this time only getting half as far as the first as his tail could only coil up part of the way. He let out a hiss as new splotches of crimson dripped through the bandages.

“No, stop!” Izuku yelled as the reality of the waking world slammed into him hard enough to make his vision spin. Oh no wait, that was because he stood up too fast.

The mer growled at him between pained breaths. He reached his hands forward, grabbing the edges of the door frame before he attempted to pull himself that way. Dark scales fought against light tiles to try and move forward.

“Shit,” Izuku swore.

The merman was able to pull himself just far enough so that his head crossed the threshold of the door before he collapsed. His chest rose rapidly as he beat his fist against the ground. Between pants, hoarse, frustrated Mertongue escaped his lips. His grand escape had amounted to all but a tail length's drag across the floor before he ran out of strength.

With a growing headache, Izuku flipped on the lights. “And just where exactly did you think you were going?” 

Obviously, it was a rhetorical question. The merman was trying to get back to the ocean. He was out of his element. He wanted to go home. A cold shiver went Izuku spine at the thought of being in the mer’s metaphorical shoes: gravely injured, forcefully trapped in the ocean by a person who, despite  having his best interest at heart, couldn’t even speak your language and failed miserably to replicate his basic survival needs.

Yet, unless they somehow managed to discover a way to magically solve all these problems and questions, like it or not, this was the best and the only thing they had going for them.

With a deflating sigh, he approached the now grumbling sea boy.

“I know this isn’t ideal,” Izuku said softly as he kneeled next to the mer. “I want to make you better as soon as possible so you can go back to the ocean too, but we can’t do that if you keep opening your wounds like that.” Izuku frowned as he looked up and down the angry lump on the floor and scrutinized the wounds. It didn’t seem like many reopened, despite the extreme activity; only the harpoon wound seemed to be leaking a steady reserve of scarlet. Still, nowhere as serious as it was earlier. 

“Let’s get you in some fresh wrappings.” His eyes looked over to the deep pink nose wrinkled up. “And some freshwater too.” That honestly might have been part of the mer’s discomfort.

Izuku shuffled on his knees over to the tub to start the drainage of the cold, stale water, before turning back to the merman. This was going to be awkward with his current position and stiff muscles from sleeping on the floor the entire day. So, he extended an open hand. “Can you help me—?”

The moment his appendage crossed some invisible bubble into the merman territory, he lashed out with his arm. He backhanded him and stared with a fire so hot it could melt metal. He started barking in Mertongue; the words were sharp with many loud growls, hisses, and a trill Izuku couldn’t even dream of recreating. Some of the words sounded vaguely familiar, a deep, guttural snarl that sounded even more hate-filled than the rest. It took Izuku a moment to realize that it was familiar because he kept repeating that same word after the harpoon was removed.

Izuku’s eyes blinked to attention as the mer struggled to push himself up. His arms were shaking like taut ropes, threatening to fall at any moment.

“No, don’t do that!” he shouted. “Please let me help you!”. Izuku dove forward to grab the mer around the chest just before he face-planted into the carpet, his arms unable to hold the weight of his own body any longer. Izuku let out a sigh of relief as the merman’s body stiffen in his hold. Good! Now all he had to do was maneuver him around so—Izuku’s foot slipped on the damp floor and lost his balance. 

In an instant, Ikuku was tumbling backward. The momentum brought the mer right along with him. He couldn’t brace himself as his head hit the tiled floor and stars filled his vision. Izuku wheezed as the merman snaked on top of his chest.

“S-Sorry,” Izuku apologized as his vision slowly cleared. “That likely—” he stopped when he felt the pin-point pricks close over his jugular. Slowly, he looked down to see the mer’s jaws pressed precariously against his neck.

The merman let out a low, intimidating growl that vibrated into Izuku’s vulnerable skin when he dared to swallow.

Izuku was frozen even as chilling sweat ran down his neck. It was obvious from the start that the mer was a predator, but he let himself get roped in by his appearance and forgotten that tidbit of information. Even if the merman was a lot weaker than him right now, this was a checkmate. All it would take is one wrong move, one snap of the predator’s teeth and he would be done for. Dead. Game over. He hesitantly looked towards the fiery gems currently trying to burn a hole through him—that, or swallow him whole, he thought.

When their eyes met, the throaty rumble intensified, and the narrowed silts watched for his next move. Despite his depleted state, all of his fins were flared out in what was clearly a display of aggression. A warning. A dare. He was challenging him to do something.

Izuku didn’t know what, if anything, would appease the heated mer and make him release his esophagus, but he had to try something. Without breaking eye contact, Izuku spoke. The fear was laced into his voice, but he tried to keep it from cracking as he said “R-Really? Y-You’re going to kill me after I saved you?”

Another cautionary snarl erupted from the very pit of the merman’s chest. And Izuku could feel it reverberate against his throat when teeth pressed down tighter, pushing little dives into the skin. Still no blood. 

“N-No. You don’t want to kill me, do you? Or else you would’ve killed me already,” Izuku stated, his muscles in his neck were cramping, but he was slowly regained some confidence in spite of being at the mercy of the spiky beast.

The merman fins shook as he let out a snarl that only rose in volume, until it was the only sound in the room. His grip didn’t loosen, but it didn’t press further either.

Izuku could have been reading this all wrong honestly., He knew this. But with their chests pressed against each other, their heartbeats practically touching and racing at the same pace, he decided to do something that might mark his own end. Izuku clenched and unclenched his hand. 

“I know that to you, I’m just another human and honestly, I’m not anything special. But even though you don’t understand me, I want you to know I’m never going to hurt you… on purpose.” He added that last part after thinking of the mess that was the previous morning. “The fact that you exist is amazing. I want to get to know you better, learn everything there is to know about you. And then… maybe… I was hoping we could become… friends?” Izuku wavered as he made his move. He brought his hand up to the back of the locks of damp, blond spikes and petted them.

The growling stopped the instant his hand met the back of the mer’s head. His body went rigid, and his fins seemed to shudder. Red eyes, still locked in combat with Izuku’s, blew wide in surprise.

Izuku smiled. His sneak attack seemed to work, so far. Feeling confident after his first attack, in the face of the lingering pressure on this throat, he drew his other hand. He allowed it to run up and down the mer’s slippery back in a soothing rhythm. There were little ridges along his spine; not quite fins, but more like scales domed out in a matter almost definitely designed for water dynamics while swimming. God, it would be amazing to see him swim in his peak condition.

The mer held his stance. He let out some halfhearted grunts, his eyes peering daggers of perplexity and querying before growing silent again, as if conflicted or confused as to how to react with this turn of events.

This continued for minutes, unreadable eyes looking him over in serious consideration. Izuku honestly didn’t know what he was doing anymore. He thought this was helping—and maybe it was, he wasn’t dead after all—but nothing else was happening other than the progression of a glorious headache from the catalytic fall, and the growing irritation of the weird way his—now soaked—shirt was bunching up at an awkward place on his spine.

And then finally, the merman broke their eye contact with a deep puff that misted his skin. Moments later, Izuku felt the teeth slowly leave his neck altogether. Still on his chest, the mer turned his head down and to the side so Izuku couldn’t see an inch of his face behind his bush of blond hair.

Izuku blinked, then exhaled in relief. It seemed that he had been allowed to live. 

“Um, okay then. So, what now?”

He got his answer in the form of a grumpy stomach growl.


“What would a merman want to eat,” Izuku mumbled to himself as he opened the overstocked fridge. “Fish of course… but I don’t think I have any—ah!” As he pushed aside the container of orange juice he bought, he found a package with a couple of average-sized tilapia fish filets. “I guess I need to thank Mom for this… I don’t know how well fish sticks would have worked.” He grabbed the fish and looked it over. It probably wouldn’t be enough, but it would certainly be a start and should give himself enough time to run to the store to grab some more.

A small plea from his stomach reminded him that he only inhaled two banana muffins today and that he should probably get something to eat for himself as well. He reached for the cupboard only to take notice of the state of his hands. Black grim crescent moons under his nails, red painting every crack and scratch of his hand and the pulsing red scape the mer gave him crusted over painfully. He wrinkled his face in disgust. Right, he hadn’t had a chance to bathe yet...oh god, he ate those muffins with filthy hands! The blood, the grime, and who knows what else—

Taking deep breaths, he willed the queasiness from his system and methodically washed his hands up to his elbows . Once he was satisfied, he fashioned himself up a simple PB&J. An old classic for sure, but it was something the curb his hunger and get back to the merman as soon as possible. He placed both meals onto plates and started back towards the master bath. 

As he neared the bedroom, the sound of the faucet squeaking on and off had him rolling his eyes. Almost certain of the scene that would await him, he hurried up. He’d known this was going to happen. When he originally turned on the water to refill the tub, the merman—despite trying to feint disinterest—was mystified with childlike wonder at the magic of what a lever could do. 

And just as he expected, when he walked past the door to the bathroom, he found the mer inquisitively turning on and off the small lever, water sloshing over the rim of the tub with each twist the experiment. On, and off. On, and off.

The mer caught sight of Izuku at the doorway before he could even say a word. His face morphed from innocent curiosity to what Izuku was learning was his resting jeer. He started yelling at him again in Mertongue as he sat up straight in the tub, splashing water all over the floor in the process.

The coverup was obvious though, and Izuku chuckled at the mer’s unintentional cuteness. It honestly must have been something else to see indoor plumbing for the first time. He placed the plates on the counter and approached the tub. “Having freshwater is good but,” Izuku kept sure the mer’s eyes were on his hands as he flicked the little lever,  “everything in moderation.” The water level started going down through the tub’s drain.

Even with the superficially fed up look, the mer kept his eyes on him as he showed him how to unplug the tub and drain some of the excess water. If someday they got around to communicating more efficiently with one another, he would explain how it actually worked. But this way at least, he (hopefully) wouldn’t flood his parents’ bathroom.

With the tub now taken care of, Izuku grabbed the mer’s plate of fish and brought it over to him. “I know it’s likely not what you are used to, but hopefully it will do for now.”

Red eyes narrowed on the filets. His nose flared as he sniffed the air. He brought his head closer, so it was hovering just above the plate and suddenly Izuku regretted not just placing it down in front of him if the merman should go into a frenzy of some sort and decide to take a finger or two for a side. But the mer’s nose scrunched up and he let out a growl at the food. He jerked his body back, turned his head to the side with a huff and crossed his arms like a child refusing to eat their vegetables.

Izuku frowned. “I know it’s not exactly fresh, but you need to eat, and this is the best I have.” He said before offering the plate again.

The mer rumbled, his eyes pointed while he glared at him over a cold shoulder.

“Come on, please?” Izuku pleads in a sweet voice, the plate now resting on the edge of the tub.

A small vein popped on the side of the mer’s forehead and he turned to face Izuku. His hands gripped the side of the tub as he lifted himself slightly as he sat up so he would be shouting down to him. It was a short rant, well compared to a couple of his previous ones with a couple of uses of that one pattern that has been steadily becoming more familiar. After it was done, the mer’s mouth pulled tight and let out a grunt like a sigh as he looked at Izuku and grumbled again. He lifted a hand, damp and dripping with water, and sharply pointed at Izuku.

Izuku’s eyes widen in astonishment. “M-Me?” He questioned as he too pointed to himself.

The mermaid gave a small nod. He processed to open his mouth wide, his lips pulled back to show his teeth before he clinked them together two times. Then finally he pointed to the plate of fish. He then pointed to himself before repeating the same motions of mashing his teeth before pointing to the food.

“Y-You want me to eat it first?” Izuku asked as he put the pieces together. His brows knitted together, and a grimace stretched across his face as he looked at the fish. “It’s not really sashimi quality fish. I can’t eat that unless I cook it first or I would get sick,” Izuku mumbled as a light bulb went off inside his head. He looked up to the mer, he tilted his chin forward, a smug smirk on his face.

“Sorry,” Izuku said with an apologetic smile. “That is pretty gross, just offering you old, raw fish.”  He sighs. “However, that does make things more difficult,” he says, taking the fish away and grabbing his own food in the process. “It means I have to go to the market every day for fresh fish—I can hear my wallet crying.” He takes a bit out of his sandwich, the jelly squirting out the side onto his hand. “But how about right now?” Izuku continued to mutter as he paced on the bathroom floor, food still in his mouth. “The merman is likely staving… I wonder if he will accept the fish cooked. That would make things easier at least. But---"

The mer let out a grunt to grab his attention.

Izuku blinked and turned back to the tub. “O-oh, sorry. I was talking out loud again, wasn’t I?”

However, the mer’s eyes were not looking at him, but instead lower to what was in his hand, his head slightly tilted to the side. He pointed at the sandwich in his hand and said something in Mertongue with an inflection at the end.

Izuku blinked and looked down. “My sandwich?” He walked back to the tub, confused, and kneeled. “It’s just a peanut butter and jelly sandwich,” he said, turning over the sandwich to show the mer up close. “I guess you wouldn’t have seen a sandwich before either,” he said with a chuckle.

The merman sat up, leaning over the side of the tub to look at the sandwich. He sniffed the bread curiously, examining the bite missing where the gooey insides were leaking out.

“Um… I would ask if you want to try, but I don’t think peanut butter, jelly, or processed grain is part of your natural—”

The merman took a bite.


Izuku could only sit owlishly as the mer then processed to snatch the rest of the sandwich from his hand and wolf it down in seconds; a satisfying smack of his lips as he finished.

Was that okay? Can Mers just eat regular, every day human food without any problems? He assumed, since he was smart enough not to take old fish, he would know if he could or could not eat something… hopefully. And if he could eat human foods without an issue, it would make things a hundred-thousand times easier while he was here recovering.

The mer turned his attention back to Izuku, or more specifically his hand still covered in sticky jelly, with hungry eyes.

“D-Do you want more?” Izuku question, quickly hiding his hand behind his back before the Mer got any bad ideas.

Once again, his answer came in the form of a stomach growl. However, this time it was accompanied by the mer’s ravenous lick of the lips, sharp teeth glinting.


The merman let out a happy sigh, his stomach slightly extended from a belly full of peanut butter and jelly sandwiches. On the floor lay two empty plates, two dirty butter knives in now half-empty jars of peanut butter and jelly, and the emptied sleeve of bread as between the two of them, they ate the entire loaf.

“You feeling better now? Less cranky?” Izuku asked with a yawn. He slept the entire day today, but the second he had a full stomach, he was practically falling asleep all over again.

His eyes closed, he let out a little warble. He wasn’t the only one still sleepy it seemed.

Izuku smiled as he admired the blond’s rare pleasant expression. So much had happened, and he could hardly believe it. At this time yesterday, he’d been struggling to go to sleep and now—well—he had a merman in his bathtub. An ill-tempered one for sure, littering his body with scratch marks and bruises; pressing his teeth against his neck threatening to bite down. It was strange. It wasn’t like it wasn't scary at all, but he wasn’t panicking. And Izuku...he’d once started freaking out by just walking into a crowded restaurant with his parents, arms numb, heart racing, dizziness, but now? He’d been inches away from death and in comparison, he’d been as cool as a cucumber. Did he always know the merman wasn’t actually going to go through with his threat? Or was it something else, he wasn’t sure. All he knew was that his mother would be freaking out right now if she saw him in this state. She would likely forbid him from getting too close to this wild and dangerous creature. But he wanted to know more.

“Hey,” Izuku said, breaking the silence.

The mer rumbled and his eyes cracked open a sliver; clearly not pleased at the disturbance.

Izuku sat up right next to the mer and watched to keep sure his eyes were on him. Just like in the movie , he thought before pointing to himself. “Izuku. I-ZU-KU,” he repeated enunciating each syllable while continually pointing to himself.  

The mer’s eyes opened a little more, his head tilting to the side.

Izuku tried it again. And then again, until the blond’s red eyes lit up in realization. He felt giddy as the merman’s scowl lips changed, perking in movement before suddenly stopping. His face morphed back to his resting sneer before turning his head away.

Deflating, he looked to the ground in defeat. It seemed like he had it for a second there, but maybe it was too much to hope for  the mer to just start speaking Japanese. Hell, he was sure it would be basically, if not straight up, impossible for him to be able to replicate many of the sounds the mer makes in his language. It doesn’t mean he will stop trying. He wants to know more about the merman, and maybe of those answers will only be possible if they can talk to eat other instead of just mimicking everything out. Maybe sign language… but that meant he would also have to learn sign language. But that shouldn’t be too hard, he already knows some of the basics and they can learn—


Izuku’s eyes shot up.

The mer’s face was scrunched up as if he was in pain, and his teeth pulled back as he tried it again. “ID-E-U-KU,” he growled and tried again.

“I-ZU-KU,” Izuku repeated, trying his best to show the mer how to move his mouth to get the correct sounds while holding in his smile.

He tried again but always seemed to get caught with the “Z” sound. He got it once or twice separate from his name, but the moment he tried to put it together, it would all fall apart, greatly frustrating the mer. “DE-KU,” he repeated for the fifth time in a row instead of “Izuku.” His brows were tilted forty-five degrees as he fumed at his own, continuous mistakes in saying his name. He balled up his fist and slammed it into the water angry, sending water showering across the room.

At this rate, he runs the chance of discouraging the mer before they even really began. So, Izuku bite his lip and nodded. “Yes. You are right. DE-KU,” he repeated.

The mer stop his splashes and looked at him.

He repeated himself, pointing at himself just as he was doing before. “DE-KU. It’s okay if you call me Deku.”

The mer’s eyes narrowed, his face pulled an annoyed pout. It was written on his face that he knew what Izuku was doing, but after a deep breath, he said. “Deku.”

“Yes,” Izuku said happily. “I’m Deku.” He pointed to himself. This was great. They were really getting somewhere now! Now all that they needed to do was—

The merman suddenly spoke up.


The merman frowned. His eyes glared at him, “KA-TSUKI,” he repeated louder this time. He used his thumb to point to the center of his chest. His name.

“KA-STU-KI,” Izuku tried to recreate the sounds individually.

“TSUKI!” The mer shouted and he moved to his throat as he trilled the second part of his name. “TSUKI!”

“TSU-KI,” Izuku tried again, even trying to imitate the vibrate but he sounded more like his mother trying to roll her Rs in Spanish.

The merman, Katsuki, groaned as Izuku kept trying. After a while, he brought a hand to his face to massage his temples as Izuku continued butchering his name. Finally, the mer slammed his fist into the water and yelled at him what Izuku could only presume was to stop.

“I’m sorry,” Izuku said in a small voice. “I-I just don’t think I can recreate some of those noises… but I want to be able to call you something and I just can’t call you Ka.” Izuku pondered for a second, looking at the annoyed merman leering back at him, his head half-submerged in the water; his tail was completely over the other end of the tub with the tips threatening to touch the floor. It was sure it was meant to be menacing, but as a bubble popped to the surface, Izuku couldn’t find it anything but cute.

“How about, Kacchan?” A cute name for an unintentionally cute merman. “Kacchan?” He asked as he pointed to the mer.

The mer raised to the surface, so his mouth was above the water. “Katsuki,” he said before submerging again.

Izuku frowned. “I can’t say that, and you know it,” he said, putting his hands on his hips. “Deku,” he said pointing to himself. “Kacchan?” he asked, pointing to him hopefully.

The mer’s head completely disappeared under the water. 

Chapter Text

Happy Boi



Katsuki closed his eyes and let the bubbles shoot out of his nose. This little tide pool the human put him in was unnerving. Even the water felt weird, and that was not even mentioning it was far too small for him. He could just call upon more water with a turn of those shiny metal numbs; one made it hot, the other made it cold and when they were used together, they actually made a bearable temperature. Then, just as easily, he could make it disappear in a hole at the bottom to who knows where. Coupled with the human’s unnatural, canned suns that burned more vibrantly than anything they could ever hope to possess, it was annoying. He was annoying. 

Stupid human. 

It was all that fucking plankton-brained bastard’s fault. Katsuki was fine on his own, why the hell did he follow him? Eijiro’s bright ass red scales were like an angler fish’s lure for those damn humans, and those humans were not like the others. When he returned to the pod, he was going to feed that seaweed for brains to the sharks. But even as he was thinking that, Katsuki’s eyes cracked open and he ghosted his hand over his wrapped tail where the humans’ barbed metal pierced him. When he closed his eyes, he could still see the blinding light, the pointed weapon, the echoing sound of silence as Katsuki pushed him out of the way moments before it fatality pierced Eijiro. “What would Pinky do if you never come home?” 

Katsuki picked at the grime under his scales around his hip fins where a nasty friction burn pulled up some scales. It was going to hurt like a motherfucker to have so many scales regrow at the same time, not to mention the tooth. But he had done it. He got away bleeding and restrained and then eluded the death that stalked him just long enough to get to the secluded beach. He knew he didn’t have time to fuck around, his vision had already gone blurry. Cut himself free and give those idiots humans firsthand experience seeing the fastest Mer in these waters—or at least that was the plan.

Katsuki’s ear fins twitched as he started to hear a faint humming. Cautiously, he rose to the surface and looked towards the human making the sound. He was swinging his hips slightly, bobbing to the tune of his own creation while his hands were busy twisting a cloth over a bucket. Disgusting, discolored water dripped from the rag before he went and started wiping the perfectly smooth ground no artisan could hope to achieve. 

Then that stupid human had to come along. 

Kastsuki had thought he was caught by this mysterious human when he approached him in the rocks—though honestly, he still kind of was after all—but he wasn’t going to go down without a fight. It might not have been much, but he could take down two or three of those agents of plague before he went down. But as the human came closer, there was a strange nagging in the back of his brain that told him this particular human was familiar. Was he one of those fuckers on those fancy looking boats that often floated around the coast and threw shit into the water? No. This memory was farther back and not colored by disgust and anger. And then it hit him like a tidal wave. This was the idiot boy he saved when he was little more than a pup. 

And now he found him again at the same beach to repay his debt by finishing him off. His blood boiled. He never put much thought in what the old farts said about humans—they were waves of disease and destruction, unreasonable monsters that heralded the end times. It was a bunch of bullshit. They were just some assholes that needed to be taught a lesson. It was why he always gave little heed to their warnings and went closer to humans than any other wished to dare. He never directly interacted with them, minus this green-eyed idiot, but he wished he could watch those ridiculous humans’ faces when they discovered all the garbage they threw into the water appear back on their pretty little boats, with interest of course. 

After Katsuki got in a good show of just how sharp his teeth were, the human started leaking from his eyes and his lip wavered as he spoke. This was the first of many things this human did that faltered Katsuki’s guard. He didn’t speak like those humans did—there was sadness in his voice. Then, just as suddenly, he hit himself before his speaking pattern changed again. It became slow and deliberate and he simultaneously motioned to himself, looking like he had to shit before pointing to the ocean. By the second time he did it, Katsuki realized the monkey was trying to communicate with him. Did humans even do that outside of songs from the past anymore?

But, as the light of the boat came around the corner, he saw it. He saw the fear in those green pools… He was just as afraid of them. Then, as he stared him down, he saw determination, resolve, hope. He didn’t know what this human wanted—yet—but at the very least, he knew he wasn’t with them. 

Those same green eyes finally noticed Katsuki staring at him over his shoulder. He lowered the rag and giggled, with that stupid warm smile on his lips and his stupid rosy cheeks with all those silly little dots. 

So fucking annoying, Katsuki thought as he looked away. He easily figured out the human was “cleaning” this weird room with that poisoned smelling water. He didn’t understand human logic at all. Clean with poison, sounds smart. Even though he didn’t want to, over time, his eyes trailed back to the figure kneeled over on the ground. He was slowly working his way across the floor with his little bucket and rag, but Katsuki’s sharp eyes noticed something. There were still streaks of red in the spot he just “finished.” Stupid human couldn’t even do his own stupid job right. 

“Deku,” Katsuki spoke the human’s (almost) name. 

The human jumped, nearly knocking over the bucket in the process. He slowly turned to look at him like a wide-eyed fish. His hand was clutching the cloth over his heart. 

Katsuki clicked his teeth and pointed to the spot. 

Green-tinted hair bobbed like waves and he looked between him and the spot, confusion splashed plainly across his face.

“You really are stupid,” Katsuki said as he rolled his eyes. He imitated the same scrubbing motion he was just using to clean. “If you are going to do something, at least do it right.” 

The human just sat there stunned, his eyes not seeing as thoughts seemed to run wild in his head. And here he thought the morons that followed him around were slow. Finally, the human started to smile. His eyes sparkled like a pool of water reflecting the night sky as he nodded his head up and down before he went back to get the area he missed. He figured out that seemed to be the human version of “yes” and the first time he did it, the human acted as if he taught a sponge to talk. 

To say this human was weird would have been an understatement. He was constantly doing things that, even for regular humans’ oddities, didn’t make any sense to Katsuki. 

How his small body had picked him up and carried him away from the ocean as if it was pup’s play. How he brought him to this small, enclosed area, blinded him with those tiny but powerful suns, and then started laughing at him only to grow silent as he looked at him with such soft tenderness. How he rambled forever, knowing full well that Katsuki couldn’t understand a lick. He smiled when he laughed at him and looked in pain as Katsuki recoiled in his own. This was not the humankind he was told to fear. And then he turned around and couldn’t even take the net off right, causing the metal to be dislodged. 

Katsuki fought hard against the darkness that had quickly approached. If he gave in, he was dead, was the only thought going through his mind. His body felt like stones. His eyes could barely make out air in front of him. He ripped something to shreds between his teeth. The human kept trying to help him, even after Katsuki slammed him with his tail and raked his arms with his nails. But at some point, his body stopped listening to him. He couldn’t move. Paralyzed. The last thing he remembered hearing was the human repeating words he didn’t know but could guess at their meaning— “Don’t worry. I’ll save you. I’ll save you.” 

And then he had woken up. 

His mind was fuzzier than a sea bunny as he looked around the strange, enclosed space. He couldn’t remember what happened, why he was here, or even where here was. A numb pain cavorted across his body. Strange white fabric covered its epicenters. When he heard a small rumbling noise, his head jolted over to the small lump curled up on the ground he had overlooked before. Everything that happened hit him all at once as he looked at the unassuming human with his mouth gaping open like a fish. He was even loud in his sleep?

This human treated him and took a beating in the process… he saved him. But why? Was it a way to repay his debt from all those seasons ago? No, that would be too simple. He wouldn’t have put himself in such danger and taken so much abuse from him. Besides, humans always, always, wanted something… The question was, what did this one want from him? Did he want to keep him as some kind of pet? Put him in a tank like the stories warned? No, that didn’t seem right either. He looked at him with such… wonder, softness… fondness? Katsuki shot up from the tub, luckily not waking the human in the process. It was so obvious—why did any Mer outside his own pod ever do anything so painstakingly nice that so unambiguously impaired them? 

They wanted to fucking mate him. 

He was easily the most sought-after tail in this quadrant of the ocean, even with his “disagreeable past-time.” He was strong, fast, damn good looking, and his proudly shimmering scales showed he was as healthy as two Mers. His had courters since he was barely of age, hoping to woo him and curve his “volatile nature” into something “presentable.” Fuck that shit. 

He had to get out. He was sure if he could get back to the ocean, he could get back to the pod even in this state. Hell, seaweed for brain was likely still looking for him. That Mer was as dense as a rock and just as hard to budge when he put his mind to it. Yes, this would work. All he had to do was get out of the water and—

Of course, that was not how it happened. It was never that simple. He couldn’t control the speed he dropped out of the tub—his arms felt like jellyfish under him. When he hit the ground, the noise woke the sleeping human. 

Bleary green eyes looked at him. His hand came up to rub his eye as his mouth hung open as if he was waiting for something to swim right in. 

Katsuki, very unsuccessfully, tried to make his escape. He couldn’t even make it to the threshold to the next area before his body gave out on him. He swore at his own incapability.

The human looked down at him as he clicked on the lights. He asked him a question in a condescending tone. 

It annoyed the ever-loving shit out of Katsuki.

After a moment, the human drew close, still talking down to him despite his softening voice. He shuffled over to the pool that held him and did something in there that he couldn’t see. He would later learn he pulled up the thing that drained the water away. As the human returned, he extended a hand forward. Katsuki was having none of that. 

He slapped the appendage away and bore into him. “Fuck that shit!” He started yelling. “Fuck you! You think just because you saved my gods damn life that you get the right to fuck me? You have another fucking thing coming!”

His offending hand rested over his chest. Green eyes looked back to him, hurt and confused.

 “What? You actually thought I was just going to start fucking presenting to my hero?” he spat at him. “Think again.” 

Katsuki tried to lift himself up, tired of this bullshit of being looked down on by that stupid asshat idiot, but his arms were fighting him. It honestly might have been easier to change the tides of the ocean than to simply sit the fuck up right then. But moments before his arms gave in, he felt the human wrap his arms around him in a far too familiar of a fashion, causing Katsuki to stiffen. He couldn’t believe how forward this human was. In the next moments, the human was holding him tightly as he slipped and fell onto his back. Katsuki snapped. 

While the human was wheezing, Katsuki fought through the pain to flip over, determined to show this idiot human who was in charge. He lowered his head and opened his jaw wide to fit as much of the human’s vulnerable neck in his mouth at once. 

For once, the human finally was still and quiet. 

Katsuki glared at the human. He wasn’t going to be anyone’s bitch, let alone some stupid human with a good guy, hero complex. Katsuki had been challenged for dominance far too many times for him to keep track of. Most the guppies knew well enough to submit to him if he got to the point of pinning them down, but every so often there were some that would be so foolish as to try to fight him. He hated the taste of their blood in his mouth, but damn it if he was just going to back down. He wasn’t going to submit to anyone. 

That statement still rings true.

Katsuki's grip on the tub tightened. “Deku,” Katsuki hissed as he pointed to yet another spot the damn human missed. He could swear at this point the human was doing this on purpose. The human had been very deliberately saying and then repeating what had been doing. “Cleaning the floor… Cleaning the sink… Cleaning the wall…” 

It didn’t take him long to put together that “Cleaning the…” was the word meant for the act of cleaning, while whatever the last word was referred to whatever he was cleaning at that moment. It was a childish game, not helped by how he was speaking like you would for a very young pup. But Katsuki very well couldn’t be unable to speak to the person that was courting him.

But every time he looks into those deep pools of happiness he couldn’t help but overlap them with the fear and confusion they held just a short time before. He was pinning him, their eyes locked and Katsuki gave him a warning growl as the challenge officially began. His fins were spread as in custom despite the pain, his heart was racing, and the human spoke.

His words were laced with fear as it cracked halfway through his question. 

Katsuki snarled from the pit of his body. Give up now, you damn human. His jaw tightened and he could feel the pulsing of his blood just below the surface. 

The human was terrified, but he didn’t back down, never once looking away. He asked another question. His throat bobbed as he gulped. 

Katsuki fins flared in a full display of his presence. He hissed again since the damn human wasn’t getting the message. Submit or die. 

But he didn’t.

His eyes looked like pools, threatening to spill over at any moment as his heart picked up speed. He kept talking as if Katsuki could suddenly understand him. He kept talking in the face of the teeth at his throat. He kept talking, desperately trying to get his message across—confidence, admiration, and finally hope. And then his hand brushed the back of Katsuki’s head.

Katsuki tensed. What was this? It wasn’t an attack? He wasn’t trying to get him to release his hold. Nor was he submitting… He was doing neither. He was challenging him right back, head-on… but he wasn’t fighting him for it. What was going on? 

Just as Katsuki didn’t think he could get any more confused, a second hand came to join the first in his wave-like motion up and down his spine. The human smiled at him as if it were the most natural thing to do. The deepest of algae green eyes sparkled with mysterious wonder that called to be explored.

Katsuki didn’t know what to do with this. The thrashing of his heart, the uncertainty in his head. The human refused to give Katsuki control, but he wasn’t attempting to take it away either. He was just letting it be—treading in place while the tides swelled and receded. It was unnatural as so many things humans did. He tried to hiss and growl, hoping to get some kind of reaction but even on his ears, they sounded weak. Just as confused and lost as he was. 

He didn’t understand. Was this just how humans worked? Did they all fight against the natural order to get what they want? They don’t do what makes sense, they only do what they want. But wait. Did that mean that this human wanted to mate with him no matter what… but didn’t want to control and force him to do so? 


Katsuki sighed as he watched Deku as he wiped the precipitation from his forehead after dropping the rag into the bucket and standing up. It’s weird, Katsuki has never really gotten a chance to watch a human, unobscured but they… leak a lot more that he would have expected. 

But that shitty Deku was the first one he chose to let court him… but it was not like Katsuki was actually going to mate with him. He was just humoring him. And if that meant he got more of those delicious… what ever the fuck they were, it might not even be so bad.

Deku looked at him with his hands on his hips. Looking around the room, he asked, “~~~~ you ~~~~? ~~~~ clean?” It was a little different than before, but only just. It sounded a lot like “cleaning” but shorter while looking around the room. Was he asking if everything was finally clean? 

Katsuki looked around the room. Deku—with his help, of course—actually did a pretty good job. The floor shone a pearly white and the seafoam walls were spotless. The metal and stone fixtures Deku called “sink” glimmered in the presence of the “lights.” He even got a steppy thing that he stood on to reach the tiny splatters on the “ceiling.”

Katsuki turned back to Deku only to wrinkle his nose. There was one thing left to clean. The human’s outer wraps looked disgusting, stained a deep reddish-brown and looked irritatingly stiff. Flakes of dried blood peeled off his exposed limbs, some from him other from the wounds he inflicted. Parts of his hair were completely matted down and honestly looked crusty. Not to mention, even over the chemically scent, Katsuki could smell him from here. 

“Deku,” he said, pointing directly at the human. 

Deku blinked in confusion. He turned around to look around behind him. 

“Fucking idiot,” Katsuki swore before preparing his vocal cords for what was next. “Deku,” he hissed to get the human’s attention again. Katsuki frowned as he concentrated on getting each syllable right. “C-Cl-Clean-ing. Cleaning the Deku.” The words felt foreign on his tongue but he thought he did it right. 

Deku dropped the rag. His hands flew up to cover his mouth as a squeaky noise he didn’t know humans were able to create slipped through. 

Katsuki fins lowered as embarrassment rushed through his veins. He did it wrong. Fuck.

However, in the next moment, Deku had lept the short distance between them, knelt on the ground, and put his hands on top of his. He nodded his head wildly. “Yes, yes, yes. Deku ~~~~ the cleaning! Kacchan, you’re ~~~~!” He smiled and let out a pearl of giddy laughter that brushed Katsuki's face. He was so cu—

Katsuki retreated under the water. It wasn’t running away—it was a strategic retreat, gods damn! Yeah, that was right. Deku was just too close. He was playing dirty, acting so happy and cute right up in his face. It hasn’t even been half a day since I decided you can court me, you damn human. Don’t get so cocky thinking I’ll just start being a blushing angel for you.  

“Kacchan?” The confused voice reverberated through the shallow water. “I’m sorry I~~~~” 

Good, you better be apologetic , Katsuki thought with a small snort. As the bubbles passed by Katsuki’s face, he got an idea. He opened his lips and held the weird tasting water in mouth before quickly splashing to the surface.

Deku halted his monologue. His eyes went wide in fear. He knew what was coming, but he was powerless to stop it. He tried to cover his face with his arms, but Katsuki had already started his watery attack. He yelped and fell on his ass as Katsuki drenched him with a mouth full of water. Droplets of light pink dropped to the clean floor as the water mixed with the dried blood left in his hair and coverings. 

Katsuki couldn’t hold in the laughter that erupted from the pit of his gut. Looking down to the wet, bemused human, he pointed to himself before repeating darkly, “Cleaning the Deku.” If his human was going to play dirty, Katsiki was going to clean him personally. 

Unfortunately, he was only able to hit the human two more times before he escaped. Once more from the front while he was trying to stand up and the last time he nailed him right in the back as he was running away squealing like a dolphin. 

Coward. Face your punishment like a man. 

Katsuki yawned as he settled himself back on in the “bathtub.” It was getting dark out again, even though it was hard to tell with the human’s lights. He had only been awake for a short while and hadn’t really done much of anything, but he already felt completely drained. He knew it was because he was low on blood—how long Deku had to clean was proof of just how much he lost—but it was annoying all the same. 

Katsuki lazily looked around his surroundings, since he hadn’t really gotten a chance to yet and Deku was taking his sweet ass time doing… whatever he was doing. The room was a fair-sized space and felt just unnecessarily bright, which was only intensified by the reflective surface wall above the rock counter of the sink. Directly behind him, there was an opaque, grooved glass that went to the ceiling and seemed to loop around the other side from what he could see in the reflection. The bathtub itself was pressed against the wall with about a spread hand width of space for shit to be placed down. 

Within his reach on this surface, there was a metal shelf not too far from his head. It was packed to the brim with those annoying containers that polluted his waters, plastered with colorful pictures and filled with strange colors. Beside them on either side, there were baskets made with a hard, tan-colored fiber Katsuki didn’t recognize. Inside the first were seashell-shaped approximations that were soft and slippery to the touch. They smelled sweet, but when he gave one a small lick, an overpowering chemically taste filled his mouth. 

After throwing the disgusting thing across the room, he turned his attention to the other basket with an equally as sweet smell. This one held strange balls in it that appeared at first to have an almost sand-like texture. He tipped the basket forward and poked one. The moment he did, it darkened in color and started to erode right under his finger. Curiosity pushed him to investigate further, but between his tiredness and the surprise of it seemingly melting in his hands, the basket with the rest of the balls slipped back and tipped over, causing them all to cascade into the water. 


His eyes shot open without a hint of the weariness from before as they all started fizzing. Bubbles, colors, and scents overflowed his senses. He tried to grab the closest one, a greenish colored one, but it whizzed around in his palm. It let out tiny bubbles, making it difficult to grab and only really serving to make it dissolve faster. 

He was finally able to grab it and throw it back into the upturned basket. It was now only half the size it was previously. and instead of smooth edges, it was practically falling apart. There was still a dozen more in the water, many out of reach on the underside of his tail. 

“Fuck, fuck, fuck, fuck, FUCK.” He swore as the colors were mixing together in a mukery gray color and the smell was becoming overwhelming. “DEKU!” Katsuki screamed. In his panic to get another one of those evil balls out, he knocked over one of the containers of colored liquid. Gods damn his luck, the lid was not properly sealed, and its contents were now also pouring into the tub. 

“DEKU!” he screamed again, as gods damn foamy bubbles started to overpopulate the tub. Where the FUCK was that idiot human, he thought as tried to splash the bubble and the crumbling leftovers of the balls away, but it only seemed to serve to make more bubbles. What kind of madness was this? 

“Deku, I swear if you don’t ass in here right now I’ll” 

“Kacchan?” the stupid human yelled before appearing moments later in the threshold. He actually seemed damper than when he left. His hair laid heavy on his head. Water dripped down his legs and arms, and the only thing he wore was one of those fluffy white cloths. 

His eyes became comically large as he saw Katsuki surrounded by a literal mountain of bubbles and human bullshit.

“Don’t just stand there slackjawed, fucking help me!” Katsuki shrieked as he tried to keep his head above the bubbles. 

Saying the human word for “help” seemed to snap the idiot out of his stupor. He nodded. “... help you, Kacchan.” He said before charging headfirst into the room…  only to slip on the fake shell he threw earlier. 

“GODS DAMN IT DEKU !” he hollered. “WATCH WHERE YOU’RE Katsuki stopped all at once as he noticed the cloth the human was wearing had come undone as he fell. 

Katsuki blinked in confusion as he looked between the human’s legs. It was hairy, with much thicker curls than the ones on top of his head, but that wasn’t really what he cared about. What was that? Wait, was that his… dick? Why did it look that way and what was that under it? Why was it so big? Wait. WHAT WAS IT DOING OUT?! 

His mouth slowly fell open. Veins popped in his forehead before he roared. “YOU THINK JUST BECAUSE I ALLOWED YOU TO COURT ME WE WOULD MATE RIGHT NOW?!?!”

Chapter Text

Izuku stood on the fine sand of the quiet beach. The sun hung heavily in the tired sky, casting warm rays of crimson and gold. It painted the cool mist in the air a rosy tone, but his eyes could only see the black caudal fins of the merman’s tail as they dipped below the ocean’s waves for the last time. He knew this day would come, the day the mer would disappear back into the ocean for good, but he didn’t think he was ready.

The moment red eyes locked with those foamy crests, he was already far away in a place Izuku could never dream of reaching. He didn’t even look back. 

Tears stung Izuku’s eyes before falling to the sand below. He didn’t even get to say goodbye. He wanted more. He wanted to learn more about him. He wanted to know everything about him: every skill, every secret, every reason. He wanted to know if he recognized him. He wanted to know why he saved him that day. He wanted to know why the thought of never seeing him again made his chest hurt so bad. He wanted to go after him. He wasn’t too far away . Maybe if he could just get to him beg him to promise he would return, promise they could still see one another then maybe it would be okay.

But he couldn’t move.

The calm waters twisted in malicious, dark coils as they completely engulfed the sun. The waves that gently lapped the shore shredded the coastline in engorged whips. His heart flew in his chest as the ice-cold breakers slammed into his legs. Seaweed slapped against his face. He was a fixture on this beach, his legs lifeless as stone. Only his eyes moved, watching the spot where Kacchan disappeared. He opened his mouth to call for the mer’s help, but the moment his jaw unsealed, water filled his lungs with burning liquid.

He couldn’t breathe.

His eyes became unfocused as his stone body sunk down. He sunk farther and farther until no light remained in the crushing pressure of the bottom of the ocean.


Izuku’s eyes snapped open. Gasping for breath, his hand clenched his shirt over his drumming heart. He shot upright ninety degrees at the hip. His body screamed at him from the sharp movement and pain radiated around his lower back. His mind started to calm in the tranquil, sun-filled room; his nightmare faded into the recesses of his mind. 

What had woken him? he wondered, as his eyes slowly wandered the room. He was on his parents’ bed, feet facing the headboard. He had moved his pillow to the other end to give him an easy line of sight to the attached bathroom. Even though he didn’t sleep on the floor for a second night, his body ached more than ever from his spectacular fall followed by Kacchan’s…  Kacchan! 

Despite his body still protesting, he swung his legs over the side of the tall, fluffy bed. He shambled his way over to the bathroom, only to let out a sigh of relief. The mer was still right where he left him. His head was tilted to the side as he peacefully slumbered. 

His fins shifted as his chest imperceptibly rose and fell. He only needed one breath for every four of Izuku’s. The crease that normally divided his blond brows was smooth. He really was strangely adorable when he wasn’t sullen.

Well no, that was a lie. He was incredibly adorable the previous night too—face completely red with anger, bubbles overflowing from the tub, thoroughly encompassing the mer in their sweet-smelling dungeon. Izuku could hit himself for leaving his mother’s bath supplies within reach. It wasn’t like he thought of Katsuki as a child or an animal, but the mer was an incredibly curious creature. It was only a matter of time before something happened, but as he looked back on it now, he really wished he had his phone so he could have taken a picture of the red-faced mer peeking out of a bathtub full of bubbles. 

Izuku quietly walked over to the tub as he noticed the nearly dry towel. His nose wrinkled momentarily as it adjusted to the overpowering floral and citrus scent. After Kacchan’s little bath bomb explosion, Izuku likely had the sweetest smelling merman in all of the seven seas. Not that he was saying Katsuki smell particularly foul before. And he still smelled this strongly after Izuku (not so easily) sprayed him down. 

It was actually a pretty heavy struggle. 

It was less than a meter to the walk-in shower, but Izuku walked away with a few more nibble wounds. He knew from personal experience, if the mer wanted to, he could shred his flesh in an instant. So, Izuku thought, because his teeth barely broke the surface meant he wasn’t actually trying to hurt him. He was just showing his frustration from being attacked by pink bubbles. 

His only saving grace came after he started draining the tub, when he left the mer for a minute to run back to his room and put on a fresh pair of shorts and a T-shirt. By the time he returned, red eyes looked him over from the cool drizzle and he let out an exasperated huff before settling coiled muscles. Now if only Kacchan would have helped him and not lay stubbornly limp with a smirk on his face. And that’s how he ended up taking a second shower that night, this time fully clothed. 

Izuku hummed as he shook his head. One day he hoped he would understand what was swimming through that merman’s mind. Some day. 

Izuku placed the newly soaked towel back onto the exposed tail.The moment it touches the mer’s scales, the mer’s eyelids started to flutter. 

“De-ku?” Kacchan questioned.

“Yes, Kacchan. Sorry, I woke you up.”

The mer let out a yawn. As drowsy, red eyes opened, Izuku made a mental note to add the fact mers yawn to his notebook. The mer tried to sit up, only to wince and recoil with a hiss. 

“Is the medicine wearing off?” Izuku asked with a frown. He waved his hands to gain the mer’s attention and asked him simply, “Pain?” while making a distressed expression. 

Kacchan nodded. 

Izuku gave a nod of his own. “Me too,” he said before walking over to the counter. He grabbed the pill bottle he left by the sink and tipped out enough for both of them. After filling a glass of water for himself, he brought the pills back over to Kacchan. 

The mer allowed the pills to be dropped in his open palm. He popped them into his mouth before submerging himself under the water. 

Izuku chuckled. It had taken a lot of effort to get the mer to take the painkillers. He had refused them until he realized what it was supposed to do. Needless to say, some nibbled fingers and half a dozen spat up pills on the floor were casualties in the mer’s stubbornness. Izuku was worried at first that giving the merman human medication would cause adverse reactions, but seeing how much pain Kacchan was in, Izuku decided to try a small dose and keep a sharp eye on him. So far everything seemed good. 

Izuku dropped the pills in his own mouth and lifted his glass of water to take a drink. 

Diiing Dooong.

Izuku inhaled sharply at the sound of the doorbell. A brisk knock followed, and he started to cough as the water went down the wrong tube. 

Kacchan’s head shot out of the water. His eyes darted around the room. “Deku?!” As soon as he saw Izuku, no doubt red in the face as he struggled to breathe, his eyes narrowed. A deep growl emitted from his throat and all of his fins raised at once. He bared his teeth as he attempted to pull himself out of the tub. 

Izuku shook his head. His eyes were watering and his throat burned, but he was able to cough out a “no” after a couple of attempts. He forced  enough air into his lungs to add, “It’s okay Kacchan.” He mustered the best smile he could through his wheezing and sputtering. 

The mer paused. His fins fluttered and his head tilted slightly as he looked to him. “O-kay?” he questioned with a level of understanding of the word despite its unfamiliarity on his tongue. 

Izuku nodded. “Yes, okay.”

The doorbell rang again, causing the blond to tense up again. His pupils dilated.  

“Don’t worry, Kacchan.” Izuku’s voice sounded hoarse but the coughing stopped. “I’ll go see who that is and be right back, okay?”

Red eyes met his green and held for just a moment before the mer settled back into the tub. 

“Thank you, Kacchan,” Izuku said as he headed towards the door. As he left, he heard the merman grumpily mutter behind him. 

Izuku quickly hobbled to the door, joints popping in the process as they stretched. He took a peek out the window as he passed. A white van was parked in the driveway next to his Nokio. Even before he got to the door, he could hear loud muttering from behind it. 

“Don’t forget, I called some people in to look at the pool,” All Might’s voice chimed in his head. 

Izuku cursed. He completely forgot they were coming. He slid to a halt in front of the front door and threw it open. Bowing his head, he said, “I’m so sorry I made you-”

“Are you Izuku?”

“Huh?” Izuku looked up. Standing before him was a tall, middle-aged man in a brown jumpsuit. He was bulky and heavy as a cement truck, but his square-shaped face held a smile as he held a phone to his ear. “Um, yes?” Izuku answered. 

The man nodded. “Here,” he said before thrusting the phone towards Izuku. 

Izuku blinked. He looked between the man and the phone for a moment before finally taking it. The man rubbing his temple near his silver hairline, as if to combat a growing headache. Izuku hesitantly brought the phone to his ear. “H-Hello?” 

There was a moment of silence before a voice screamed, “IZUKU!” 

Izuku jerked the phone away from his ear as his mother’s shrill voice blasted over the speakers. Ice-cold dread washed over him as he realized forgetting about the repairs was the least of his worries.

“Do you have any clue how worried I’ve been?”


“Your father said not to worry, but then you didn’t call last night and didn’t answer any of my calls, I thought you were dead. Are you trying to put your mother in an early grave?”

“No, Mom, I—”

“Then what were you trying to do?”


The old repairman waved to grab Izuku’s attention. “Excuse my intrusion,” he whispered, “but before you get too caught up in… family matters, can you direct me and the boys to the pool?” 

Izuku looked over to the van to see two other repairmen around his age in the same brown jumpers. The first was an enthusiastic man with short brown hair and fell into the category of exceptionally average looking. The second was a short, plump man with light blue tinted colored hair and a perpetual apologetic expression. 

“Umm, yes, of course.” Izuku stepped aside to let them in. 

“Of course, what?” his mother questioned.

Izuku had to stop himself from rolling his eyes despite her not being here. “No mom, I wasn’t talking to you. I was talking to the repairmen.”

There was a small hum from over the phone.

“Wow dude, are you okay?” the shorter one asked, looking genuinely worried.

“Yeah, it looked like you picked a fight with a garbage disposal,” the second one jabbed lightheartedly. 

“Picked a fight with a WHAT?!” Her screech was loud enough he was sure dogs two counties over could have heard her, let alone the two workers. 

Izuku’s lips pulled tight as he glared at them.

“Sorry,” they mouthed, but it was already too late. The damage was done.

“Izuku, have you been in a fight?”

“No mom-”

“But you are hurt? Izuku, what happened?” She didn’t even give him a chance to speak before continuing. “God, I knew this was a bad idea. You weren’t ready for this. I told Toshi you weren’t ready for this. Don’t worry, Izuku, let me grab my purse and I’ll drive right-”

“MOM,” Izuku snapped, raising his voice. “Please just let me SPEAK!” 

The phone went silent.

Izuku immediately regretted raising his voice as moments later, he heard the telltale signs of his mother’s waterworks. 

Mom cried a lot when he was a child, even more so after the divorce. It hurt so much, he would cuddle up in her arms and tell her “I am here,” quoting All Might’s catch phrase. Her overprotective tendencies got better when All Might came into her life, but since Izuku decided to take a year off, those darker moments were intruding once more.

“Mom, I’m sorry… I didn’t mean to raise my voice like that,” Izuku said rubbing the back of his head. He looked up to the three men still standing stiffly in the foyer. Putting a hand to the receiver, he whispered, “Down the hall on the left. It will be the third door on the right. You’ll know it's the right one because it’s the modern door that looks out of place.” 

They gave him a grateful nod before booking it in the direction of the broken pool. 

Izuku took a deep breath before finding himself wandering in the opposite direction, back towards the master room. 

“Mom? Please, mom, I’m sorry,” he apologized again.

His mother hiccupped in his ear. He had no doubt by this point that her eyes were puffy and red, just like his own eyes get when his tears start flowing. He hated it when she cried the most. It made him feel like the bad guy. He knew she was just worried about him, but her over concern was one of the biggest reasons he had to leave. He loved her to death, nothing would change that… but her love was suffocating at times. 

“I-Izuku, I’m sorry. I know you are an adult, and I know it’s only been two days since we last talked, but I was still scared gray that I couldn’t reach you. I thought something horrible must have happened, and now I hear you are hurt and I…” She sniffled heavily as her voice cracked. 


“J-Just tell me what’s going on, Izuku? If there is something wrong, you know you can tell me… tell us, and we are more than willing to help you.” 

Izuku gulped as his eyes glanced into the bathroom. Kacchan was still sitting in the tub. However, upon his return to the threshold of the door, he sat up a bit once more. His ear fins flicked curiously and betrayed his otherwise indifferent expression. 

In the panic-filled haze of those first few moments after finding Kacchan, the only thing on Izuku’s mind was calling his parents. He needed their help, he was in over his head caring for this merman with a potentially dire harpoon wound. He didn’t know how, but after stabilizing the mer that urgent necessity drifted further from the front of his mind until it was all but forgotten.

And then Izuku caught a glimpse at himself in the mirror. No wonder those two thought the need to comment on it. Despite no longer having a caked-on layer of grim and dried blood, he was still a far cry from the smooth baby face guy who drove into town a couple of days ago. A large purple-blue bruise marred his cheek and he had scratches and bruises up and down his arms and legs. 

What would his mother do if she saw him like this? 

What would she say when she hears he was threatened at gunpoint by poachers? 

What would she think about Kacchan if she knew he did this to him? 

Would she care most of the scratches came during those desperate minutes of pain induced flailing? Or that they were just nips and he wasn’t really biting him to harm him? Or that when he pinned him and threatened to rip out his throat, he was just scared and needed a hug?

Or would she call Kacchan a feral animal and demand he never gets close to him again? 

He didn’t want that. He didn’t want his mother to worry about him. He didn’t want to be torn away from Kacchan when they were finally starting to get somewhere. He didn’t want to do this, but he needed to prevent that from happening.

“I-I dropped my phone… in the toilet,” he said while looking at his mer. 

“Y-you, what?” she asked incredulously. 

“D-don’t make me repeat myself, mom. It’s already embarrassing enough as is,” Izuku joked, hoping she wouldn’t hear the twinge in his voice. “I was half asleep and went into the bathroom… and it kind of just… plopped… out of my pocket… into the bowl…” He began to sweat. His eyes darted around the room as he paced. His mouth pulled tight to stop his rambling. He was the worse liar. The absolute worse. His only possible saving grace was the fact she couldn’t actually see his face contort in his obvious deception. But he couldn’t help but notice the perplexed look a pair of red eyes was giving him. 

You ... You dropped your phone into the toilet,” his mother repeated. For a hairpin moment, when he heard her take a deep breath, Izuku worried she wouldn’t buy it . 

“How irresponsible, Izuku!” 

Izuku blinked. Wait, did she actually buy that?

“You just got that phone two months ago and then you go and throw all that money into the toilet?” she scolded. “You should have just said that from the start. I'm glad it wasn’t anything more serious—you had your mother worried. But what was it doing so precariously in your pocket? Your phone should be—”

There was a hearty laugh from over the phone. “Inko dear, I don’t think you have any right lecturing anyone about taking care of their phone. You’ve had seven phones in just as many years, and if I’m not mistaken, you once even deep cleaned your phone in the washer the same day we got it,” All Might said. 

Izuku could picture All Might bringing Inko in for a hug. All Might knew it was the easiest and fastest way to calm his wife. “I think Izuku’s allowed one accident with his otherwise scratchless record.”

“W-well, he still should have contacted us and told us about it,” Mom argued back. 

“True,” All Might hummed. “But I’m sure our son was just trying to take responsibility into his own hands before running to us for help. That's the whole purpose of him staying at the summer home correct?” Izuku heard a beep. “Isn’t that right, my boy?”


“I-um, yes!” Izuku scrambled for words as his feet started moving again. He paced the length of the room, but Kacchan was never out of his sight for more than a couple of seconds at a time. “I thought… hoped. Well, I’ve been trying to dry it out using some white rice. I-I was hoping I could get it dried out and working again before worrying you guys and having to buy a new one. I’m sorry. I really am...” that I had to lie to you

“And what about what those men said?” Inko asked. “You look like you ‘picked a fight with the garbage disposal’?” 

Izuku nervously laughed. “T-they were overreacting a bit. It’s only a few small cuts I got making dinner last night. I accidentally dropped my plate while trying to catch my glass before it fell… So now I owe you guys a plate and a glass.” He chuckled again because that was not suspicious in the slightest. 

“Izuku… are you sure you’re going to be okay by yourself?” his mother questioned, her voice laced with worry and doubt. 

“I’m sure,” Izuku said quickly. “Yesterday I just caught a case of butterfingers because of nerves. I’m sure in the next couple of days things will settle down and everything will be fine.” 

“And if it’s not, there is no shame in coming home, sweetie!” his mother chimed. “Even if it’s just for the weekend… or if you need help with your laundry. Anything you need help with, we will be there.” 

“Okay, Mom.” Izuku rolled his eyes only for them to meet agitated red ones. His tail flicked over the edge of the cramped tub. “Um, actually… I have a question.”

“Of course, sweetie. Ask us—”

“For Dad, um, only?” Izuku interrupted.

“I’m sure whatever it is, you can just ask the both of us,” she stated matter-of-factly.

All Might coughed. “Inko, I think your son wants to have a man-to-man conversation.” 

There was a moment of silence on the other end of the phone where neither of his parents spoke, but after those agonizing couple of seconds, mother bear relented. 

“Okay, Toshi,” she said softly. “I’ll go start some lunch and get your afternoon medicine ready.”

“Thank you, Inko,” All Might said before Izuku heard the faint sound of a kiss. There was another beep from the other line, and after a few moments of the phone being moved around, All Might asked, “So you have a question for me?” 

“Yes, um it’s a bit of an outlandish one…” Izuku trailed off, not sure how to ask the needed question without it being too suspicious. 

After a moment, All Might asked in a hushed voice, “Is it relationship troubles again? I know you are a healthy, responsible young man. I know your mother would likely vote against it, but I trust you that if you want to have your sweetheart over, I’ll be okay with it as long as you promise to practice safe—”

“No, no, nope, no,” Izuku interrupted him forcefully. “I’m not dating anyone right now and I’m not… just no.” His face was nearly as scarlet as the merman’s eyes.

“Oh,” was the only thing Izuku heard for a moment. “Sorry, I’ve seemed to have read the situation wrong.”

Just a bit.

He cleared his throat. “What did you want to ask me then?”

Take a moment’s break from his pacing, he looked over to the black-tailed mer. “I was hoping because it's being worked on right now, that we can make the pool be a… saltwater pool?” 

For the third time, the phone went dead silent.

Izuku knew he was asking the most suspicious question possible. He might as well have started with “I’m hiding something BIG.” He didn’t know much about saltwater pools other than they were a huge investment; they likely need special equipment because of salt’s corrosive properties. 

He had grown close to his childhood hero turned adoptive father. He was his confidant, the one person who didn’t dismiss his claims about the mermaid(man) rescuer. He would know he wouldn’t ask such a question without one hell of a reason… and he really did in the form of his finned friend. 

Kacchan needed a better place to heal than a bathtub filled with table salt. He needed the room to stretch his tail. And maybe that would improve his overall mood. Maybe. 

“Izuku… Why would—”


Izuku jumped so high he nearly hit the ceiling. He quickly turned to see a face etched with frustration; veins popped on his forehead, his brows steeped together forming a powerful “V”, a sneer filled to the brim with sharp teeth. His eyes locked with Izuku as he slapped the water with his extending and contracting fins before he started to yell. There were plenty of hisses and growls, with sprinklings of his name and the word that Izuku was quickly believing must be some kind of swear. 

Izuku put a palm on the receiver and dashed into the bathroom at top speed. 

He looked the mer over. Nothing seemed out of the ordinary, at least nothing like the last time he was shouting his name. His bandages also seemed to be holding up well. He wasn’t hungry, or at least he wasn’t signaling for food. 

“Deku,” Kacchan clicked his teeth together. He folded his arms across his chest, his eyes narrowed. 

Izuku frowned. Did he want attention? 

“Izuku,” All Might said.

The mer’s eyes widen suddenly as his ear fins flicker. Oh! That's right, he likely didn’t know what a phone was and was wondering why Izuku was talking to himself. 

Keeping his eyes on the mer, Izuku answered, “Um, yes. Sorry, I’m still here.” Izuku gulped. Why was he so nervous about this. This was his dad… All Might! The hero to people and wildlife alike. Him knowing about Kacchan wouldn’t be a bad thing. His legs began to shake, so he kneeled, leaning his back against the tub.

Kacchan’s tail brushed against his shoulder and when he looked up, red eyes stared back inquisitively. 

Izuku smiled. Without thinking, he reached up and caressed the fins that draped over his shoulder. Just like the rest of his body, it had the slippery second skin. The membrane, while appearing thin and looking nearly transparent, was actually surprisingly ductile and strong. It was similar to his ribs, which appeared to be hard and were incredibly flexible. 

The mer stiffened., His eyes widened at the contact. His lower lip quivered and his tail twitched but didn’t pull away. 

I will keep Kacchan safe no matter what. 

“I fou—”

“You never stop surprising me,” All Might said. He chuckled lightly. “Izuku, my boy, you do know the pool is already a saltwater pool, right?” 

This time, Izuku was struck silent. “Wait, what?”

Chapter Text

Katsuki yawned as his eyes slowly drifted closed from the delicate fingers that ran along the ridges of his tail fins. He didn’t normally let anyone touch his tail; the stupid human should have felt honored Katsuki was letting him do this for him. He had every right to reject Deku’s tactless advance and clumsy performance, but he would give the human a pass this once because… it actually felt kind of good. 

But only kind of.

And only because he was still exhausted in addition to everything being so fucking sore. His wounds still ached, and that bitter medicine Deku gave him every couple of hours only took the bite away. Also he was stuck in this tiny pool of water, he couldn’t stretch at all, and when he tried to get out for a bit, Deku just kept putting him right fucking back here. So actually the longer he thought about it, it was all Deku’s fault. Him massaging Katsuki’s tail now was actually the least he could do.

Katsuki huffed. He let his fins ruffle and he scooched his tail a little farther out of the water as to present the human with more area to cover. His auditory fins twitched as they caught the—definitely not cute—giggle from the human. He would have been laughed out of his pod if they could see him now. 

He slowly opened his eyes and looked into the clear, lightly rippling water. He hadn't put much thought into how his pod was doing without him. They probably thought he was dead. Eijiro was the last one to see him after he saved his stupid red tail. There was no way they would ever think a human of all creatures would save him and then proceed to start courting him. Hell, he was still having a hard time believing it and he was living it. Eijiro was likely blaming himself, Mina would be trying to console him, Denki and Hanta would be starting a search party in hopes of finding him, and his mother… 

The old sea hag would be able to handle things. He wasn’t the first she lost. 

Katsuki’s hands lightly run over the littering of wounds that covered his body. It would take at least a moon for it to be possible to make the return trip, a couple more until he was completely healed. Katsuki’s eyes drifted over to the bright human as his light fingers worked their way up his tail. He didn’t know Deku’s intentions or how serious he actually was about this courting attempt. Did he intend to keep him here after he recovered? Would he willingly let him go back? He knew if it came down to it—if he was fully healed—he would be able to make it back to the ocean assuming the sun wasn’t directly overhead. And he would have to wait that long since he couldn’t chance reopening his wounds.

But once he left… would he ever come back? Would he even want to? It wasn’t like he was actually intending to make this human his mate. He was just using him because it was convenient. He wasn’t such an easy catch that a couple of nice sentiments, some food, or a presence that could brighten the entire room would win him over.


Well, maybe there wasn’t any harm coming back and visiting.

A small frown formed on Deku’s lips before his green eyes glance back to him. Deku seemed shocked that Katsuki was staring at him, but that quickly passed in favor of a stiff smile. His fingers pulled away from his scales unceremoniously quickly, giving Katsuki an odd sense of loss. 

“Sorry, Kacchan,” Deku apologized as he stood. “I ~~~~~~ ~~~~~~ ~~~~, okay?” he asked while holding up that strange, black toy he had been talking to. 

He had seen humans on boats using similar toys before, and he thought it ludicrous that so many humans could be interested in them. It was young pups’ play to hold conch shells to their ear fins and listen, but apparently, this game spread well into maturity for humans. Katsuki wasn’t sure which reason was more likely — humans were entertained by the most mundane things or they really were just so childish by nature that such low comprehension games were fun.

He didn’t know why his human thought now was the time he wanted to play, considering just a couple of minutes previously he was scaring away whatever beast was making that “dinging” noise. But his face looked stressed as he paced around and occasionally looked at him. Maybe it was some kind of coping mechanism? Coping for what, he wasn’t sure but the longer Deku did it, the more it started to piss him off so he snapped at the dark-haired human. He wanted his Deku to stop walking around and talking to that stupid brick.

Deku did come over to him in an instant. He looked surprised at his outburst but it was just logical. If he had to play a stupid game, he should have a least picked one they could both play. 

But what he heard next surprised him. A voice from the toy? A voice Deku answered as if he was talking to a person. It was strange but at the same time no stranger than the way humans had somehow learned to control the elements with captured suns and on-demand tempered water. So maybe there was more to this toy than the simple shells he played with as a pup. 

“Kacchan,” Deku said, bringing  Katsuki’s attention back to the present. The human started asking him several questions by the sound of it. He understood only every few words, but couldn’t make any real meaning from them until he said the word “food.” He was asking if he was hungry.

Katsuki didn’t think about it before, but now that Deku mentioned it he was getting a bit hungry. He didn’t know how he was since he was just sitting here like a barnacle for the past couple of days. At this rate by the time he gets back to his pod, he would be sporting a healthy layer of courting fat with all this inactivity and rich human foods. It wasn’t like he could refuse these wooing gestures with his current mobility limitations. If he ever wanted to heal, he had to eat. 

Katsuki sighed and nodded to the human. 

Deku smirked, showing off his dimpled cheeks. He patted Katsuki’s head, and before he could retaliate, the human was already out the door. 

“Stupid Deku,” he grumbled out loud. His hand rubbed the top of the head where the ghost of those soft fingers still tingled his skin. “Cocky asshole,” he whispered as he tried to ignore the warmth in his cheeks. 


Time passed sluggishly without the human around. Deku purposefully moved a few items out of his reach. If he wanted to experiment with them now, not that he liked smelling like flowers, he would have to get out of the tub.  

Idly, he turned his attention to his scales. While he was not notoriously known for the pretentious grooming of his scales like some Mer ( Denki ), he wasn’t a slob either. Currently, his scales reflected dully and listlessly in the artificial light. It was difficult to do with only his hands, but he started working on the scales near his hip fins and worked his fingers down. He had to be careful of the bare, tender patches that already started to itch like a bitch as the new scales came in. 

He could already see the look on Deku’s stupid face when he finally gets back here and sees his scales’ proper shine. 

Not that he was doing this for him… 

He wasn’t preening for Deku. 

He was just fucking bored and want to tidy himself up because he was a decent Mer. Showing off to the simple-minded human was just a bonus to that. 

It didn’t take him as long as he thought to clean himself up, and it wasn’t because there were a couple fewer scales to tend to. Surprisingly, his scales still held a good amount of their color and luster in the face of the stress he had been under. It was a happy little discovery, but it meant that all too soon he was once again bored without his stupid human in sight. 

Where exactly had Deku gone off to? The last couple of times he went off to gather food, it only took him a few minutes. Maybe he ran out of preserves and had to go forage for more? 

Katsuki let out a huff of air. He sat back in the tub and just tried to relax like earlier as the nagging exhaustion hadn’t completely left his body. He no more than closed his eyes before he heard a loud bang followed by yelling. Katsuki jolted up, his fins outstretched defensively. 

That wasn’t his Deku’s stupid voice. No, it was too rough to be Deku’s voice… and there was more than one. All distinctly different than his seaweed-green human. He didn’t know there were other humans here… Had they always been here? He surely would have heard them before this point if they were here, right? This was Deku’s territory, wasn’t it? Why were there other people here?


Could they have been intruders hoping to seize Deku’s territory? He didn’t have anything to base it on, but Deku’s home seemed to be pretty nice. Or at the very least, it was large in scale from what he remembered from that first night. Humans were greedy creatures—it wouldn’t be too far fetched to think that they would gang up on each other for the best dwelling. Then how did Deku come into the position of this locale? Was Deku actually really high on the food chain? He knew Deku seemed the weakling but was actually stronger than he looked… could he actually have been even stronger than he thought? 

But wait, what would that make Katsuki? Deku’s weakness? Katsuki growled at the thought. Fuck that! Katsuki was the definition of strength. He wasn’t about to be dead weight. He was not the weaker of the two.  

Katsuki gripped the sides of the tub and prepared to lift himself. He didn’t know how effective he would be out of the water and injured, but his teeth were strong and he didn’t know the meaning of the word lose. 


Katsuki blinked and looked up to see Deku standing in the door frame. His head was tilted to the side. His hands were filled with a long piece of flat wood that appeared to be steaming a strangely appetizing scent. He didn’t seem worried or preparing for a fight. There was no way he didn’t hear the other humans, so that meant… the other humans were not intruders? 

Katsuki sank back into the water.

Actually, weren’t humans also social animals? Between the little he had seen from a distance and what he was told of humans, it was far more common for humans to be in groups than to be alone. One of their greatest advantages was their numbers. 

Katsuki turned away from the curious human to hide his embarrassment. Fuck, he was really out of his element here and it was making him look stupid. This was the second time this morning he was ready to jump into a fight for this stupid human. 

Why the fuck was he so worried about Deku? 

Deku chuckled. “Sorry,” he said.

Katsuki only glanced at him from the corner of his eye as the human continued to talk. However, he was interrupted by a strange, high pitched grinding noise. It sounded like a dying animal and made it hard for Katsuki to think straight. 

Deku winced at the noise. He put down the item he was carrying and placed his hands on his ears. “Loud?”

Katsuki didn’t know what that meant but if he had to guess, it was referring to the corrupt noise. He didn’t like this “loud”—it was too booming. 

Deku left for a moment to close the doors, starting with the one in the adjacent room before returning to close the one to the room he just left. Thankfully, that did the trick. The noise was duller now, however, not completely muted. Seeming pleased with himself, Deku gathered the tray and brought it over so Katsuki could see it wasn’t the wood itself steaming, but the strange and yet delicious-smelling items on it.

Katsuki sat up in the tub, his eyes wide. Ceramic discs were filled with tiny green trees, another with oblong, white morsels stuck tightly together like a spawn of fish eggs, slabs of gold and salmon-colored… fish? That couldn’t be the fish Deku first presented to him… could it? He leaned over further to get a better whiff. He could still smell the fishiness, but the smell of death that clung to old fish was replaced with… well, he wasn’t exactly sure what. But it smelled good. Like, really good. 

So good his stomach betrayed him and growled. 

Deku giggled and Katsuki threw him a look that made him apologize again. He pointed to each goody, clear enunciating each name for him. “Broccoli. Rice. Fish.” 


“Braa-kuh-lee,” the human repeated as he scooped a bunch of tiny trees onto two flat ceramics he believed Deku called a “plates” before. Deku looked up expectantly, his hand over the second dish.

Katsuki clicked his teeth. He was treating him like a pup first learning to trill. But looking at his hopeful eyes, Katsuki relented and said, “R-Rice.” 

“Yes,” Deku nodded happily as he spooned a pile onto the plates.

His smile was contagious, as he felt a smirk spreading across his lips. “Fish,” he said confidently before Deku was even finished with the rice. 

“Yes! ~~~~ good Kacchan!” Deku commended.

Katsuki’s eyes were glued to the enticing cutlet. As Deku lifted it to the plate, he could see the flaky nature and the tender juices. He didn’t even know fish could do that. He hardly noticed his tail wagging as the human presented him with the plate of food. This was a much better presentation of courting than the first night Deku showed off his hunting skills. He lowered his head, trying to identify what these conflicting, but somehow complementary smells were. Sweet and fatty, but also… acidity? No, that wasn’t quite it either. 

Katsuki peered over to Deku. The human already had his eating sticks in his mouth, a flaky piece of fish missing from his fillet. Safe to eat—not that he actually thought his courter would try to poison him at this point. 

Not wasting a moment longer, Katsuki turned back to his food and went in for a bite. But something unexpected happened—the food hurt him. Katsuki reeled back, nearly sending the plate flying. He cocked his head, looking at the unsuspecting fish meat giving off even more steam than before as it was broken open. It wasn’t alive It shouldn’t have been able to attack him like this… What was going on?

Katsuki, slowly this time, tried to take a bite. Burning juices overflowed from the meat, far too hot for any living tissue. He tried to keep it in his mouth, balancing on his teeth so it wouldn’t hurt as much, but after a few seconds, he found he couldn’t and ended up spitting it back onto the plate. 

“What the fuck?” he growled at the food. 

Deku made a small chirp and his eyes flashed to him. His lips were pulled tight, his eyes wide with amusement. He looked moments away from bursting out into laughter. 

“Fuck you, Deku!” he yelled at the human. “Why the fuck is the food hurting me? Is this some kind of fucking joke?”  

Deku took a deep breath, but the small smirk still remained. “Sorry, ~~~ ~~~~ hot?” he asked. that word,‘hot’ sounded familiar… Oh! Katsuki looked over to the metal knob that controls the hot water. Hot was the measure of the temperature…. Wait, why the fuck was the fish hot? 

Deku shifted closer. Using the sticks to break off a piece of the fish, he brought the morsel to his mouth before blowing on it. He then held it up to Katsuki’s face. The human opened and closed his mouth, clearly hoping Katsuki would copy his ridiculous movements. 

Katsuki looked between the morsel of fish offered and then back to Deku. He rolled his eyes and gave the human a chance by opening his mouth and allowing the human to feed him. It was still warm, but no longer burning his tongue. Because of that, he could actually taste the warm fish melt in his mouth. He closed his eyes to savor the flavor on his tongue. 

“Good?” Deku asked. 

Katsuki nodded. Shit, he might have a problem going back to plain old fish after this. He opened his mouth again, his tail flickering side to side, as he waited for more. If his human was going to court him, he might as well hand feed him. 

Deku rolled his eyes, understanding he was a slave to his will. 


Katsuki leaned back, his belly once again overfilled with all the food Deku had presented him. He rubbed his slightly distended belly, he has honestly never felt this full before. Everything was delicious and new; he wouldn’t let a single piece go to waste even though he was now paying for it with a tummy ache. 

He turned his head back over to Deku. He was humming again, a soft tune unlike some of the loud, annoying music humans on boats play. Having gathered all the licked-clean dishes into a pile behind his head on the counter, Deku was preoccupied with something else entirely. 

The human had a rectangular, flat object in his lap, brown on the outside with many thin, light-colored surfaces in the middle. When Deku moved it, it kind of reminded him of how birds fly in the sky. He had yet another wooden stick. It was shorter than the two he used to feed Katsuki and himself, and it had a strange pink end that he would occasionally turn around and use. He was scratching against the lighter colored sheets at a rapid pace. 

It was starting to get annoying.

“Deku,” he grumbled. He was hoping to get a nap in after the “loud” stopped, but couldn’t if Deku was insisting on doing weird shit that makes him curious. 

Green eyes look up only to follow Katsuki’s glare at the thing in his hand. A light pink hue appeared on his cheeks as he started to ramble nervously. 

“Deku,” Katsuki interrupted. While the blubbering was just a little bit cute, if he let the human go he would just keep going and leave Katsuki just as oblivious as when he started. 

Deku looked up at Katsuki and then down again at the thing in his lap His not super cute blush was reaching his weird ears now. He took a deep breath before turning the thing in this hands around so Katsuki could see the creamed-colored insides. 

Katsuki’s eyes widened. They were covered in symbols and shapes… writing. Human writing. This wasn’t the first time he had seen the stuff—their trash is covered it in. Deku flipped over the panel to reveal another layer of writing and then another. But that wasn’t what Katsuki was truthly shocked about. No, it was the images—drawings—that littered the pages with the writing. 

They were of him. His tail. His fins. His scales. Messy lines ran into each other, shading and circles competing with hard edges to make the whole. They were unlike anything he had ever seen before. They weren’t the smooth, overtly professional style found on the humans’ trash, nor the heavily stylized art of the old ruins of his people. It was rough, genuine, alive with the feelings of its creator. 

And then Izuku turned one more leaf and he was looking himself in the face. His lips pulled back into a sneer that pulled his brows into an arch. His hair brushed out in every direction, seemingly nearly dried in the air. His eyes hard but filled with emotions so much deeper. 

His heart betrayed him as it skipped a beat. This was how Deku thought of him? He was really this interested in him that he would dredge up such an old tradition? Memorialize his image, his being, every part of him… he wanted every part of him to be remembered. 

This human… he was really serious about this. Well fuck. 

He slowly looked up to the small man attempting to hide behind his creation. Red was now the dominant color on his face. Katsuki realized he had been muttering this entire time, a steady stream of words that he wanted more than ever to understand. 

Katsuki brought his hand out of the water to reach out towards him, but surprisingly the human flinched back. He slammed the brown exteriors hiding the entirety of his gesture in an instant as he hid it behind his back. 

They stared at each other for a moment, neither daring to make a move. 

Katsuki tilted his head to the side. His ear fins flickered in his confusion. 

Deku opened his mouth before closing it once more. Katsuki could see his mind at work behind his deep green eyes. Then the human, not a stranger in doing unusual things, reopened the item to a seemingly blank page. Katsuki heard a ripping noise, and he watched in fascination how easily the material tore. Deku then used his wooden stick to write something on the piece before he crawled over to sit on his legs beside him. With his empty hand, he put his hand in the water.

“Water,” Deku said in that same teaching tone as earlier. His hands splashed around the surface of the liquid. 

Katsuki nodded to signal he understood. This wasn’t the first time he had heard this word spoken by the human. 

Deku nodded and opened his other hand to show off the piece of the material. Up close, Katsuki noticed it was like fabric, but had no visible threads as it was incredibly flat. “ Paper. ” 

“P-Pappper?” Katsuki repeated. He reached out to touch it, but Deku closed his palm and pulled his hand away.

Deku shook his head. “No water,” he said once more showing off the piece of paper. 

Katsuki’s brows press together. No Water? 

Deku showed off the piece of paper, how rigid and yet oddly flexibility it was as it was twisted and bent, and then Katsuki watched as Deku lowered it into the water. It changed colors as the water surrounded it. The small scribble on the sheet blurred by the second until it was unrecognizable. And then Deku squeezed it in his fingers, just as he had done moments before, but this time the paper broke, dissolving into pulp.

“No water,” Deku said calmly. Katsuki nodded his head, understanding.


Tomorrow would mark a quarter of a moon cycle since Deku found him on the beach. Six days of human courting. Things had fallen into a bit of a pattern for Katsuki and his human. Midmorning, Katsuki would wake up only to find the human already up and waiting for him. He was often on his “laptop” or drawing more in his “sketchbook,” both items Katsuki had learned didn’t mix with water. 

Deku would give Katsuki the warmest of smiles and say his name as if it were the most natural thing to do. Deku changed his bandages and gave him more bitter medicine before leaving for a bit to prepare “breakfast.” For the most part, the food was delicious. The only exception was the strange, milky-white drink that turned his stomach and gave him the shits. Deku apologized relentlessly for the rest of the day for that one. It was annoying. It was his own damn fault for asking him to try it despite his hesitance, so Katsuki only had himself to blame.

They spend the rest of the morning learning words. At this point, Katsuki was pretty confident he could name everything in this room, all the food Deku has brought him, and even parts of the body, both human and mer. 

While it was mostly Katsuki learning the human language, he was also trying to teach the human some Mer. It was hard since he had come to realize that humans really couldn’t articulate the different sounds correctly in tangent with the words. But the moment Deku figured out what he was trying to do, he tried his damnedest to form the words despite its impossibility.

Stupid Deku.

When the sun was high in the sky, Deku would leave again to make “lunch.” They would spend the afternoon reviewing the words from that morning, often making a game out of them, which ultimately helped to add more words to Katsuki’s vocabulary. Katsuki would end up taking a nap sometime during this time where more often than not, he would wake to Deku bringing in “dinner.” It blew his mind that humans had so many meals in a day. There were days back home when he was lucky to have one.

Why the fuck did humans need so much food? 

But finally, the evening normally found the two relaxing. Deku had seemingly become fond of tending to his tail, and if that was what made him happy, then who was he to stop his fun? But it was only fair during this time that Katsuki got a good look at what Deku had down there as well! 

So when he got the chance, he took it and grabbed one of the human’s feet! He was always curious about how they worked and why they looked so fucking weird. But the moment Katsuki had one in his hands, Deku started kicking. At first, he thought he angered the otherwise docile human, but then he started laughing, face red with an adorable pleading squeal. A mischievous smile grew on his face at that moment as he realized what was happening. Tickles. 

Needless to say, he very carefully examined Deku’s foot after that.  

The day would wrap up with Deku once again looking over his injuries before they would go to sleep. The next day would repeat the same cycle. 

But today was different.

After Deku wrapped clean bandages around his tail, he didn’t return him to the nearby tub. Instead, he carried him out of the room for the first time in days. 

“D-Deku?” he questioned as his eyes darted around the new surroundings. When it was dark, he couldn’t really absorb the scope of Deku’s home… it was huge! Windows and doors everywhere leading to entirely different rooms and openings. But he couldn’t seem to focus on any of it because he had no clue where the fuck Deku was taking him. 

He couldn’t be taking him back to the ocean for multiple reasons. The damn human wasn’t done courting him yet… was he?  Plus, while he did seem to be healing faster than normal with all the human medicine, he was nowhere near ready to make the journey home. Then could it be to see other humans? But he hadn’t heard any other humans here since the third day. And just because he trusted Deku didn’t automatically mean he trusted any of the other fucking asshole humans.

Katsuki could feel Deku’s heartbeat through his chest; it was fast, fluttering even. He looked up to the human’s face, an apprehensive crease was forming between his brows. 

Their eyes caught and Deku gave him a nervous smile as he opened one final door. 

Katsuki looked forward and his jaw dropped. It was the second most beautiful sight he had seen since he came here. 

Chapter Text

Warm, natural light flooded into the large, spacious room from the multitude of windows. Katsuki looked in awe at the semi-opaque squares as they shone brilliantly from above. He followed the gable down to the walls that were made head to ceiling of clear glass. Thin fabrics were hung over their lower halves. Against the far wall, there were more rectangles, however, while the middle one looked similar to a window, it was black in color partly reflecting the room.

He followed the natural curve of the wide-leaf plants basking in the plentiful sun around the edges of the room. He could see some human furniture: chairs, a table, and even a longer chair that looked like it could fit three humans. They were light in color with cushy-looking material not dissimilar to the thing Deku slept on. Even the floor was giving off an inviting shine. Its stylized tile work looked like the sun and waves.

But honestly, those were all afterthoughts in Katsuki’s mind as the crystal-clear water stole his attention. That water shimmered in the pleased light of the room and the smell of the fresh, salty water flooded his nose, creating an inviting call. Even from here he could tell it couldn’t have been more than three head-to-tail lengths wide and double that in length. The far end seemed to slope down a third of the way across, but still it didn’t look terribly deep. It was a far cry from the vastness of the ocean, the migrating neighborhoods of his pod, but it wasn’t meant to be that, was it?

It was a bed .

A bed in a burrow Deku prepared for him .

A bed in a burrow Deku prepared for him in Deku’s territory.

Katsuki felt the warmth leave his body as the crushing weight of the gesture hit him. He thought he had acclimated to the outlandish and forward actions of this land creature, and to an extent, he had, but it wasn’t that . It wasn’t the boldness of the act that was causing panic to run through his veins.

It was how he felt about it.

His first reaction should have been to reject it and to stop this annoyance of a courtship for the sheer audacity. They haven’t even been courting for a quarter of a cycle and this fucker was just continuously upping the ante with his gifts: from the presentation of food, the light bouts of grooming, and to this point . A fucking bed.  It was madness and he should have treated it as such. 

But for a second, he felt himself swallowed by that madness and giving in to the human’s pace. He was nearly swept away in the thoughts. He loved it.

He fucking loved it.

He didn’t understand what was happening to him. He was using the human. He just thought the stupid attempts of the stupid human would keep him amused while he healed. After he went back home, he would never need to think about him again. He had always— always —been able to wave off the advance of other Mers. The attempts were numerous and it was somewhat of a pastime of his. But this human… with each day he was finding it harder for him to do the same. For some reason words from the old hag echoed in his head.

“You were born as stubborn as bedrock, but even that will be worn away by the ocean’s waves, brat.”

Like hell he was going to let that happen! Katsuki snapped back to look at the warm body holding him, fully intending to give him hell. However, the moment he saw the freckled face, the wrath he felt evaporated.

Deku didn’t look smug. Hell, he didn’t even carry a hint of his normally unassuming jovialness. He wasn’t looking at Katsuki at all, but directly forward. The light of the shimmering water reflected in his green eyes, and for the first time, Katsuki noticed his heartbeat had quickened. Deku was… nervous?

Was he actually, for once , nervous about the boldness of his audacious courtship? “Deku?” Katsuki growled, masking his apprehension with the residue of his previous anger.

Deku jumped. His eyes snapped into focus, and he looked down at Katsuki as if he forgot he was even there.

“S-Sorry Kacchan,” Deku mumbled. There was a hesitation in his voice, even when he started to ramble like normal when nervous or excited; however, it was obvious it was the former and not the later this time. He was apologizing for the burrow and bed? Then why the fuck did he do it in the first place? Why couldn’t humans ever make any sense!

“Deku, you son of a—shiiiiit,” Katsuki hissed as his back locked up; sleeping so awkwardly in that damn tub was really starting to hurt. His lower back was hurting him almost as much as the god damn harpoon wound at this point.

“Kacchan? Are you okay?” Deku’s mutterings turned back to him as worried eyes looked over him. He couldn’t understand four out of five words the human was saying, but Katsuki  was able to catch the words “water” and “help.”

And then everything swam into place. Deku was freaking out because he knew it was too early for this. He wasn’t being arrogant or cocky… He likely even knew Katsuki might reject him completely. But he also knew that the puny bathtub was causing him pain. He prepared this earlier than appropriate—with the help of those humans he heard the other day—well aware of what might happen. He took a chance to completely ruin their courtship just to keep ensuring Katsuki was comfortable.

Katsuki sighed. He really had to double down on learning fucking human so they wouldn’t have any more misunderstandings. He raised a brow at the human, still muttering away with apologies. Katsuki leaned in so his head was against the crook of his neck and gave it a nip. “Okay, Deku. You can bring me to the water,” he said in a mix of his native tongue and Deku’s.

Deku eyes went wide at the bite to his shoulder, and a hint of his normal smile made an appearance. He nodded and brought him closer to the pool.

Katsuki turned his attention back to the quickly approaching water, his heart thumping in time with Deku’s. He repeated to himself that this wasn’t a bedding gift… Well, it was, but there was nuance to it! They were not going to consummate their pairing ye—EVER. Deku was human. They were on land. It just made logical sense some steps to be out of order. It had been generations since the last time a Mer had even spoken to a human, let alone courted each other. He was never taught how it would fucking differ.

Besides, he really just wanted to stretch his fins.

Deku stalled at the water’s edge. Katsuki could feel his grip tightening as he hung partially over the water. His body subtly shifted with the human’s form, from looking directly in front to turning towards a bent metal pole that went into the water near the human’s stairs. 

But Katsuki didn’t care about whatever the fuck Deku was doing anymore as he was already looking down at the calm water. It was so close he could almost taste it. Katsuki shifted his tail forward so that the very tips of his tail-spines run along the surface. The surface of the salt water was cool and smooth. Droplets sparkled as his fins flickered up. He wanted more. Without another moment of hesitation, Katsuki rolled himself out of the indecisive human’s arms and into the water.

Katsuki splashed down and heard the squeal of surprise from Deku, but that was already far behind him as he let himself sink to the bottom. It was refreshing, maybe even comforting, to be completely submerged, even if the water still tasted unusual. Softer? Strange. Katsuki closed his eyes and enjoyed the feeling of his gills opening up entirely.

“Kacchan?” He could hear the concerned, distorted voice of his courter.

Katsuki snickered, cracking his eyes open to see the bubbles float to the surface. He flipped himself over, and with one thrust of his tail, he shot off across to the far side of the pool. The water curled around him, covering his sore tail in its cool presence. His fins stretched out as he flipped himself end over end in the deeper waters; his tail broke the surface for just a moment. He scrunches his tail, wincing briefly  as his wounds pull, before darting across the water again. A sense of joy bubbled from grinning lips. It took being unable to swim to realize just how much he loved it. 

He swam the length of the pool, exploring every corner, every slope. It was a bit empty, but he was sure he could get Deku to bring him whatever he wanted… assuming he could convey what he wanted. 

He popped his head out of the water, just enough so his nose broke the surface. His tail lowered until its tips ran against the bottom while he treaded in place. He hated to admit it, but he needed the extra air as he panted to catch his breath. Between the injuries and the unfamiliar waters, just a couple of minutes of fun took a lot more out of him than expected. But, now with this larger pool, maybe Deku wouldn’t have to change the water so often and his gills would finally adjust to the man-made waters. 

His eyes shifted over to Deku, now standing further back with a small smile on his pink lips. When he noticed Katsuki looking at him, his smile grew and he gave a little wave. 

Katsuki smirked. With a powerful pump of his tail (likely not the best idea with his injuries), he did a small backflip. He couldn’t get enough speed in this tiny pool to rise completely out of the water, but it was enough to send a spray towards his spectator.

When he resurfaced, Deku’s mouth was open wide and he started to slap his hands together repetitively. Fucking weird. But the wild flailing of his hands seemed to be a good thing, if the rest of his expression was anything to go by. 

Katsuki’s smirk widens under the water’s surface. He repeated the flip again, this time adding a second forward flip where he held his tail out of the water for a moment. At the peak of his flip, he made sure to stretch out all of his fins and rippled them just for Deku to appreciate. 

Sure, it was showing off, but he was allowed to show off in this courtship just as much as Deku could! The thought of getting Deku flushed with embarrassment just as he had been drove Katsuki to push the extremes of his limited stamina. 

Katsuki righted himself in the water and looked back to Deku. He fully assumed the human would have at least come to the water’s edge to take a closer look at the admittedly limited showing of his fins. However, he was disappointed—pissed actually—to see him still cheering in the same spot from afar. 

Katsuki clicked his teeth. What the fuck? Were his scales and fins all of a sudden not good enough? They deserved a better reaction than that! He was the number one, most desirable Mer this side of the fucking ocean and it was not just any day he would flaunt that like some hot to trout whelp. 

He swiveled his hips and slowly floated to the shallow end of the pool. He glared at the human as he glided, letting out a low rumble from the pit of his throat. The sound traveled through his body and his fins, allowing them to shudder and splash small droplets into the air where he went. 

And then a thought passed his mind. What if he was playing right into another one of the humans’ crazy ploys? Deku wanted to see more of this rare treat, so he was purposely underplaying it to get a rise out of Katsuki and make him the fool. Well, if he wanted a fool, he was going to give it to him! 

He used his tail to stand himself in the water for a moment, flaring his fins before ultimately  splashing back into the water. He did a tight flip in the shallow water so he was looking at green eyes once more.

While he was still a tail lengths away from the pool, dark spots have appeared on Deku’s clothes from his most recent stunt. His eyebrows were pulled together with anxiety while simultaneously biting his lower lip. 

Katsuki chortled. Now he was getting somewhere. He turned onto his back and let out a couple of relaxed clicks and waited to reel the human into his trap. 

Deku shuffled on his feet. His eyes met Katsuki’s and after a moment, he took a deep breath and approached the water’s edge with a tense stride. “I’m okay. ~~~~~~~~~~ ~~ good,” Deku muttered as he lowered his bare feet into the water. 

Katsuki held still in the water and simply watched him on the calm surface. He had to wait for the perfect mo—

Deku looked over to him and gave him a smile. 

In an instant, Katsuki flipped himself over and darted over to Deku. He grabbed onto Deku’s ankles before the naive idiot could even react and pulled him in entirely. With the swift kick of his tail, he was able to bring Deku completely under with him. He was going to resurface and bark at the human for trying to play him as a fool, and this is what he deser—

A horrific scream broke Katsuki’s inner diatribe. Bubbles rose around them as the human  thrashed in his hold. Fighting him. Fighting the water for dear life. The hysterical human hit and scratched him with blunt claws trying desperately to push away from his hold. Katsuki tried to pull him closer, to calm him down but that only made him struggle harder. A flailing knee hit Katsuki in his damn harpoon wound and he lost his grip as he recoiled in pain. His vision blurred and he couldn’t react as Deku’s foot hit him square in the stomach as he scrambled away.

Katsuki didn’t even care how ethereal crimson dotted the water or fiery pain shot from the reopened wound. He surfaced to see Deku had already clawed his way back to land and was doubled over into a small, shaking ball. His eyes were closed. He held his chest as his breath came quick between coughs. 


Glossy green eyes shot open. He could see his reflection through the fearful green eyes. 

Without warning, the human bolted up and ran. His legs were unsteady, nearly tripping twice, ran into the door, and struggled to open it. He didn’t look back. He left Katsuki alone, confused, and more than anything else, hurt. 

Chapter Text

Izuku’s eyes welled up as he ran. He was barely thinking about where he needed to go; his feet just knew he had to get away. Get away from the pool. Get away from the judgmental eyes of the merman. He crashed into the door during his escape. His body felt numb, hardly feeling the impact. He flung opened the door and started down the hallway. Water dripped down his body from his wet clothes and hair. It slicked the wooden floors and made him slide everywhere.

After what seemed like minutes, he got to his room. He didn’t waste a moment before he dive-bombed his book bag, turning it upside down to empty its contents. He packed them… he knew he packed them. His mother wouldn’t have let him leave the house if he didn’t—there! The amber bottle dropped out of his bag before it spun across the floor and under his bed. Izuku cursed, throwing his bag aside and going after the pills. He grabbed it with shaking fingers, tore off the lid and swallowed the pill dry.

His entire body was a buzz. He couldn’t feel his hands or nose anymore. He felt lightheaded as each breath came faster than the last. He let out a pitiful whimper before he curled into a ball at the foot of the bed and started to cry. Big fat tears ran down his cheeks as his nose became clogged. His heart was hammering against his ribs threatening its own escape.

He hated this. He hated feeling like this. He hated being alone like this. He cursed himself for waiting until last night to lie to All Might that his phone was dead for good. He needed it right now. He wanted to talk to someone right now. Uraraka, Iida, Mom, Dad, even Todoroki. He wanted to talk to someone. He didn’t want to feel completely and utterly alone in the world. Someone to listen, someone to say they were here for him.

“B-B-Bre-eath-eath, I-I-Iz-zu-zu-ku,” he told himself. He was okay now. Safe. He took his medicine. It would start working in a handful of minutes. He didn’t have anything to panic about. He could breathe.

He wasn’t drowning.

His stomach twisted into a knot, and he started to have another coughing fit. He curled further around himself as he willed himself not to get sick. He felt cold. The clothes sticking to his body felt like anchors weighing him down. They had to go. Unemotionally, he threw off all the clothes he was wearing. He pulled up  the blanket from the bed and sat down, but once again set himself on the floor. He was too soaked for the bed.

He closed his eyes in his little cocoon. He just had to relax, calm down, and unwind while the medicine did its job. But the moment he did, the darkness closed in, and he felt the pressure push in all around him. The pressure built between his ears and his head pounded. It was becoming harder to breath. He couldn’t move his arms or legs. His lungs were filling with burning cold water.

His eyes snapped back open and he started coughing harder. He hated this. He hated he was like this. He hated feeling so weak, helpless and powerless to change. Why was he like this? Why couldn’t he just be normal? Why couldn’t he get over this fear? He was a grown ass man, afraid of ninety centimeters of water. It was pathetic… He was pathetic! He just wanted to curl up and disappear.

That day Kacchan saved him, the day he nearly drowned, haunted him. He had nightmares for months afterwards that there hadn’t been a  bright-eyed merman to save him. He just kept sinking until there was no light. He would often wake feeling like he couldn’t move; his eyes wouldn’t open and no part of his body would respond. He would start panicking thinking he actually did sink to the bottom of the ocean. He would try to open his mouth to yell for his mother, his father, All Might, anyone, even that red eyed mer to save him, but it was futile. Sometimes for minutes he would lie in panicked stillness before his body caught up with his mind and “woke up,” often covered in a cold sweat with a waterfall of tears not far behind it.

Even at that young age, he could see how stressed his mother was: between the divorce, downsizing to a smaller apartment, and working herself half to death with overtime to support them. He didn’t want to bother her and only add to her problems. But she, and the entire rest of his middle school, found out when he was invited over for a “fun” birthday party and ended up in hysterics over a kitty pool. He became known as the scaredy cat coward who needed his   mommy to come pick him up. It was a stigma he never lived down, not even when All Might became his stepfather. 

He quickly learned his classmates only started to act nicely because they wanted to meet the famous TV star. They didn’t want to be friends with him. But who would blame them?

He was a mess.

A hot fucking mess that only got worse as the years passed, and then he evolved into this current hot mess.

His mom, and later All Might, helped him by having him go to therapy. It helped… some. But it didn’t fix everything overnight. He had methods now to curve his anxiety and bouts of depression and medication for when he started having a panic attack. But the fear of the water… stuck. It took him years before he could take a bath without having to psyche himself up; that shouldn’t have been such a huge accomplishment.

Izuku took a deep breath through his mouth as he felt his heart start to steady. His eyes were finally able to focus on one thing at a time. Currently his gaze looked at the clutter littering  the floor. He knew he had to pick it up sooner than later, but he chose to wait until later. Afraid that if he moved from his small spot in the world, everything would come crashing down again.

His eyes landed on his bright red shoes; a long-time staple of his wardrobe, and his mind snapped back to the red eyes that looked at him with such chaos and confusion.


His breath faltered. He just left Kacchan there, alone and perplexed. It wouldn’t surprise him if the temperamental merman was mad at him. It was obvious he was just having a bit of fun. If he was a normal person, it would have been for him too. He knew the mer didn’t do it out of maliciousness, he just didn’t know that someone could be so outrageously afraid of a little bit of water.

Izuku didn’t blame him for what happened. If anything, it was his fault. He could see the mischievous glint in his eyes, the shrewd smirk, and the flip of his tail and fins to draw him in closer. He was beautiful, and the mer knew it. The way he moved in the water was like a work of art, even when limited by his bandaged tail. He cut through the pool like a knife through warm butter. His scales shimmered, refracting the light into bursts of color. It was drawing him in, despite his fears.

A siren's song without a sound being uttered.

The mer wore so many of his expressions on his face—something extremely helpful in their limited word economy—and he looked so happy.  It filled Izuku’s heart with joy; his grumpy fish was happy and reeled him in. He wanted to get closer, to be part of his happiness, even if he knew from the look in red eyes he was planning something. At the time, he thought he was going to get splashed, maybe even spat at again. He could have dealt with that. Now, it’s just when he opens his eyes underwater, and he falls into the past. Just a child caught in the current.

Izuku sighed. He should go talk to Kacchan and apologize. He didn’t want to go near that pool again, but he had to for Kacchan. He stood up. The blanket covering him fell to the floor, exposing himself to the world.

He should probably get dressed first.


Izuku bit his lip as he stood in front of the door, holding a platter filled with a delicious feast upon it—all of Kacchan’s favorites. The first time he was here, he stood for nearly five minutes, his hand just resting on the door handle before remembering neither had eaten anything his morning, and he should cook some brunch.

At first, he just made some toast with Kacchan’s favorite jam and some decaf coffee for himself. But then he looked at it and thought, it looked a little sad by itself. So he just started to cook more. This continued until he had, just to name a few, a tray filled with homemade hash browns, sunny side up eggs, English muffins with jam to go along with the cold toast, bacon and sausage, and even some thinly sliced smoked salmon.

He was preparing to make some pancakes to go along with it when he remembered the mer’s only seemingly food limitation; dairy. It honestly made a good bit of sense since it seemed like the ability to digest dairy after infancy was more of an acquired skilled than an inborn trait of all humans. Even he could only have so much in a day before he started regretting it tomorrow. What did shock him (and reminded him that Kacchan was a scary predator in the wild) was how he had no problem happily ripping into a steak.

Izuku took a deep breath. He had to stop procrastinating. He looked up to the door with fleeting determination. He can do this! And if not, he always had the pool net food delivery, backup option. No, he can do this. He can do this!

Before he could lose his nerve again, he swiftly opened the door only for it to collide with something when it was only part way ajar.

Not even a second later, Kacchan shrieked followed by (what he presumes to be) a string of mer curses.

Izuku’s eyes widen. He placed the tray on the floor behind him and wiggled his way through the opening into the room. As he feared, Kacchan was right there behind the door.

The mer was laying on his stomach; one of his hands was being used to support his upper half while the other one was currently holding his face. Narrowed red eyes snapped up to look at him as equally red liquid dripped to the ground from behind his hand.

“Shit,” Izuku said dropping to his knees beside the mer. “I’m sorry Kacchan.” He reached out to try and move the hand and get a better look at the nosebleed. However, the moment he touched Kacchan, the mer growled at him. This took him back, but it was not unexpected. He deserved that. Izuku motioned for the mer to tilt his head forward and then showed him where to pinch it on his own nose. Why was Kacchan behind the door? Did he crawl out of the pool over—

Izuku stopped mid thought as he looked over and saw the droplets of blood leading from the pool all the way back to the blood-soaked circle in the bandages over the harpoon injury. His wounds reopened… No, Izuku reopened his wound in the struggle. But that wasn’t all. Kacchan had new, fresh scratch wounds littered across his chest and arms, all courtesy of Izuku. Izuku’s hands clenched and his eyes sprung a fresh leak as he realized how badly he messed up. He hurt Kacchan. He hurt him a lot. He was the worst.

“I-I’m so sorry, Kacchan,” Izuku said. He had made so much progress in gaining the mer’s trust, and it might have just evaporated in an instant. He might never get it back. He flipped out on him, hurt him, and then left him alone before hurting him again. The mer might just conclude that all humans were evil creatures and no better than those poachers. “I’m sorry,” he repeated before this time going to stand. Even... if Kacchan hated him—the thought alone crushed his heart—he had to help him. “I’ll go and get—”

Before he could even turn to leave or finishing his sentence, Kacchan grabbed his leg with both arms. Izuku was taken aback by the contact. The mer’s slippery skin was warm against his exposed leg. It was like when he pulled him in… but clearly he wasn’t trying to do that now.

“No,” he growled harshly.

It took a moment for Izuku to recover, but as he did, a frown spread across his face. “Kacchan,” he said as he tried to pull away.

Kacchan tightened his grip. His eyes didn’t dare shift from their target.

“Kacchan, you’re hurt I’m just—”

“No,” Kacchan interrupted.

“No?” Izuku asked.

“I no hurt,” Kacchan sneered. A drop of blood trickled over his lips and down onto Izuku’s leg.

“Kacchan, you’re clearly hurt. Let me just go—"

“No!” Kacchan yelled before dropping into his native tongue to yell at him. He was spitting blood with each word laced with harsh chords. His fins were flared out, humming with each note of his anger. He never looked away; he only blinked with his transparent second lids. And by the time he got to the end, his chest heaving and his lower lip wavering, his eyes betrayed something else entirely as his voice cracked. Immediately, Kacchan looked down towards Izuku’s foot. His fins no longer held tension as they fell limp to either side of him.


“I sorry.”

It was barely above the silence of the room, but it was enough to bring Izuku paused. “What did you just say, Kacchan?”

“I sorry.”

He said it a little louder this time, however, Izuku still couldn’t make it out. “Kacchan, I can’t hear you. Can you—”

Kacchan head whipped up; his eyes were glowing like mini infernos, as he yelled at him as if he the words were poison on his tongue. “I sorry! Fuck . I sorry. I sorry. I fucking sorry!”

Izuku’s jaw dropped. “Kacchan… I…” He shook his head. “No Kacchan, that’s wrong,” he placed a hand on his own chest. “I’m the one that should be sorry.”

A vein popped on the merman’s forehead and his tail slammed against the ground.

“No Deku sorry.” Kacchan knocked his head to the side. “I sorry. Katsuki sorry,” he said before growling more insulting sounding words in Mer.


Kacchan bit his leg. His teeth traced his skin, threatening to pierce it if he fought. He released Deku just as suddenly as he attacked. Kacchan leered up to him, a resolute look upon his face. He was refusing any apology. Not only that, he was the one apologizing.

“Kacchan…” Izuku softly smiled.

Kacchan huffed and rolled his eyes. He finally removed one arm holding him and patted the ground. “Deku.”

Izuku blinked. Did he want him to… sit? Izuku looked nervously over to the mer’s tail and Kacchan noticed it.

“Deku,” he growled warningly. “I okay,” he said before slapping the ground again with an open palm.

“Please,” Izuku held up his pointer finger. “One minute for me to get the first aid kit and I’ll be right back.”

Kacchan frowned.

“I’ll bring in the food. I’m sure you can smell it… Well, actually maybe not with your nose like that.” Izuku rubbed the back of his neck.

At the sound of “food,” Kacchan’s ear fins perked up. He turned his head sharply to the side, a forced frown on his face. And after a moment, he said grumpily, “Okay.”


The wounds were not as bad as Izuku thought. The harpoon wound, which he was most worried about, only reopened a small bit near the large scab of the injury. By the time he even looked at it, it was already starting to close. Even still, Izuku cleared the wound carefully—which caused the eating mer to hiss and try to smack him with his tail. The scratches and nosebleeds were also minor, but he disinfected the lacerations nonetheless. When he got back to his nose, it was ever so slightly discolored, but he had already stopped bleeding.

Izuku plopped down next to the mer. He had sat up to be eye level with him, his tail folded beside him. Izuku went for a plate to dish out his own food, but stopped when he noticed something missing. He raised an eyebrow and looked at the mer. “Did you eat all the fish?”

Kacchan smirked.

Izuku shook his head and turned to eat what was left of his food. It was honestly still way too much. He only ate a little over half of it before he was stuffed. 

When he looked over to Kacchan, the poor mer looked green around the gills, but he was still trying to put more food in his mouth. He had noticed this earlier, the mer would eat just about everything put in front of him, even if he looked to be full or struggling to keep it all down. Didn’t he know they could just save it for later? Oh, wait a second. Maybe he didn’t.

“Kacchan,” Izuku called the attention of the mer, and in a moment he was distracted, he slid the nearly empty plate of food away. 

Kacchan’s eyes darted between him and the food in confusion before he snapped in anger and yelled at him. 

Izuku held up a hand. “We can save this for later,” he said. “The food will still be good.” He wasn’t sure how much of that Kacchan would understand, he seemed to have a good enough grasp on food, good, and hopefully even save. 

“But how can I show him how humans store their food… Well, maybe by actually showing him. I could bring him to the kitchen and show him the refrigerator and freezer, the cabins and containers. Actually, while I’m at it, it wouldn’t be such a bad idea to show him the rest of the house too. I know if I was in Kacchan’s shoes… er, fins, I would be curious of this foreign new world I found myself in. He’s familiar with the bathroom already, but this place is huge and I don’t think I’ve been in every room to be completely honest. It could be a bit of an adventure. Yeah! This might actually be a good—”


“Huh?” Izuku blinked before his hand flew to his lips. “I said all that out loud?”

Kacchan clicked his tongue.

Izuku felt the blush creep onto his cheeks. The merman he had known for less than a week was already used to his word vomit. Kacchan started to snicker, which only caused his blush to grow. He tried to hide behind his hands, but the mer was as fast as ever, grabbing ahold of his hands before he could lift them to his face.

“Noooo Kacchan, let me hide my shame!” Izuku whined.

“No!” Kacchan laughed harder as he held his hands in both of his own, their fingers interlocking. His scales shone brightly as his smile spread wide. Kacchan pulled him closer but Izuku pulled back; neither were going to give in that easily.  

Izuku knew the mer had slippery skin. It would be an immediate disadvantage for him, so Izuku should slip right out with just a little extra force. He started to roll onto his back, using his superior weight to his advantage. Or so he thought. 

Izuku opened his eyes as he looked up to red. His hands were pressed to either side of his head by the mer’s outstretched arms. Kacchan’s tail resting between his legs, their stomachs practically touching. 

Kacchan looked down at him smugly, his fins vibrating at his victory. He lowered his head, and Izuku’s heart started to go wild as sharp teeth playfully brushed against his partly exposed shoulder. This was just like the last time Kacchan pinned him? No, this was different. The first time was him scared and trying to defend himself. This was a bit like when puppies play with one another. They nip and bite, but not to cause harm. It was just for fun. He didn’t need to be worried, so why was his heart beating out of his chest? The only reason he could conclude was that he was still in an over-hyper state from earlier. 

Kacchan lifted his head, his spiky blond hair tickled Izuku’s cheek as he did. He was still smirking victoriously. His tail—while Izuku couldn’t see it—was flittering back and forth. 

Izuku pouted. He didn’t understand. He should have effortlessly been able to slip out of Kacchan’s hands. The mucus substance that coated his body to keep him hydrated was extremely—wait. 

Izuku moved his fingers and felt the friction of his captor’s skin. 

“Kacchan, you’re drying out.”

“Hah?” Kacchan questioned, his breath blew across Izuku’s face.

Izuku brushed his fingers tips over the mer’s finger tips. “You need to go back into the water.”

Kacchan’s smile dropped in an instant and his brows rose. He looked at Izuku, his mind racing behind his eyes before his hands pulled out of his own and crawled off him. 

“Kacchan?” Izuku took the opportunity to sit up.

Kacchan lips twitched. His eyes darted between Izuku and the tiles. He opened his mouth but immediately closed it when he looked back to Izuku. He growled something, clicking his teeth together. Izuku thought he heard him say his name. 


Suddenly, burning red eyes flashed towards him. “Deku.”

“Y-Yes?” Izuku asked, shifting back from the sudden intensity in his voice.

The mer took a deep breath as he seemed to be thinking carefully about his next words. “Deku no… water? Deku,” his face scrunched up, “afreed water?” He looked unsure, but he kept his purposeful eye contact, waiting for Izuku’s reaction. 

Izuku was dumbfounded. The mer figured it out by himself. He shouldn’t have been surprised; Kacchan has shown time and time again he was extremely intelligent. Even picking up words (albeit pronouncing it incorrectly) that he wasn’t directly taught. His mouth parted, but all he could do was a small nod. 

Kacchan swore in Mer as his body loosened up. He closed his eyes and took a deep breath. By the time he was exhaling, he was smiling.  

When he opened his eyes moments later, he said, “Deku…” His eyes darted around as he grumbled and cursed. He then started to raise his arm above his head, his fingers out pointing before he pulled it back to his chest before he repeated in a rhythmic motion with the other, repeat. He motioned his head and grumbled when he looked over and noticed Izuku’s confusion. “Water… hooman…” he said while speeding up the motion, adding a small kick. “Legs, arms go hooman water.”

Izuku tried to fight a smile. He knew the mer was being serious right now, but him flailing his arms around like that looked hilariously goofy. Once again, he wished he had his phone, so he could take a video. It almost looked like he was— 

“Oh! Swimming?” he said, copying the motion of Kacchan’s sloppy combination of a doggy paddle and freestyle. 


Izuku nodded.

Kacchan nodded, trying the word a couple of times before he continued.“Deku swimming…” Kacchan thought for a second before he reached over to Izuku. He outstretched both arms, one near the top of his head and the other at his toes. He shook his hand once before he pulled them closer together.

Izuku brought a hand to his face.“Smal-ler? Or then again, maybe younger… younger. Wait.” Izuku’s head shot up, his eyes widen. Him swimming younger? “You remember,” Izuku whispered.

Kacchan tilted his head to look up to him. 

Izuku grabbed the mer’s shoulders and looked him directly in the eyes. “You remember!” he yelled. He started to laugh, a smile spreading across his face. “All this time I thought you forgot. But, god! You actually remember when we were younger and—” 

Kacchan brows were pulled tight together. His lips twitching in agitation. 

Izuku’s hands jolted up. “I-I’m sorry. I got a little excited there.” He cleared his throat to divide the previous yammering with what he said next. “Younger.”

It took Kacchan a moment and another repetition of the word for him to nod. “Young-er,” he said before wrapping it all together. “Yes, Deku swimming younger,” he rolled his eyes at the word swimming. He patted the ground before continuing with, “no Deku swimming.” Kacchan motioned for Izuku’s current height with a tilt of his head. 

“Older,” Izuku supplied the word.

Kacchan nodded. “Older,” he repeated. 

Izuku gave the mer a weak smile. He remembered Izuku could swim, barely, when he was younger. “Yes, it was that day I became afraid of the water. Younger Deku became afraid of water that day I met you, Kacchan.” 

Kacchan frowned. He brought his hands to his throat and his chest stopped it’s rising; he was holding his breath. 

Izuku nodded again. “Yes, drowning. I’m afraid of drowning.” He motioned above his head. “When water is above my head, I’m afraid of drowning,” his voice was hallowed, clouded with the dull fear living just a couple of meters away.

A smug grin spread across Kacchan’s lips. He straightened his hunched back, sitting up straight so he was looking slightly down at Izuku. He fluttered out his fins, letting them catch the light for a moment before he said brashly, “I help Deku.”


“I help Deku no afreed of water,” he said, beating on his chest.

Izuku shook his head. “No, no. Kacchan. You can’t help me with my fear.” Many before the mer have tried to do just that. His family, friends, a therapist. Most recently it was one of Uraraka’s old friends from elementary school, Asui. She just so happened to go to the same college as Izuku, and she was the star of the swimming team,. His fear got the best of him before his first lesson, and he ended up blowing her off. She was nice, he knew she wasn’t mad, but he found himself awkwardly avoiding her since. 

Izuku frowned, meeting the mer’s glare. “It’s more complicated than—” 

Kacchan growled. His eyes started to burn brighter. “No. I HELP Deku no afreed of water,” he repeated, pounding his fist against his chest. 

“Kacchan, it’s impossible. I can’t. I—”

Kacchan exploded. “NO, no. Deku no fucking droowing. I fucking save. I save younger fucking Deku. I save older fucking Deku. Deku no afreed.” He was breathing quickly. Izuku noticed it earlier, but the longer the mer was out of the water, the more ragged it sounded and the rougher his voice became. He panted to catch his breath, his eyes locked with Izuku’s for the umpteenth time this morning. And then his sharp eyes softened. He took one more gulp of air and said, “I… here. Deku no afreed water. I here.” 

“It’s fine now. Why? Because I am here!” 

Izuku’s breath caught in his throat as he thought of All Might’s old motto. It was strange even thinking it since All Might was his stepfather now, and he hads heard these words repeated to him in their glory many times (mostly as a joke) since his childhood and into his adulthood, but there was something so… authentic about the mer’s broken Japanese promise. It reminded him how it felt as a young child listening to those words on TV. It held something, something he thought he became desensitized to with years of fear and doubt. So simply, but so powerful. It made him want to recapture it. 

Izuku’s vision began to water; he was such a cry baby that even the mildest things could get him crying, it seemed. He lowered his head as he tried to wipe the tears from his eyes, and he felt a hand on his head. He hiccuped and looked up to see Kacchan. The mer’s eyes were gentle as he lightly brushed his hair. In the next moment, Izuku found himself being forcefully pulled against the mer’s damp chest. There was an awkward moment when nothing happened, and then he felt a tickle in his hair and a pull on his earlobe.

Izuku giggled. Was this how mers comforted each other? While damp, it was also pretty nice. He wasn't ever alone, was he? This entire time Kacchan was worried about him. He even got out of the pool and was trying to find him. He hadn't realized they had already become so close. Friends with a merman! His outwardly aggressive, but secretly kind fish. 

He let his eyes close and just listened to the soft croon the mer was making. It was soothing like a lullaby. Between his full belly and emotionally exhausting morning, he could feel himself drifting away. But as his consciousness was slipping, his mind wanted one more thing. It wanted to be free from his fear. And maybe if it was Kacchan…


Katsuki let out a puff of air. It was getting harder for him to breathe normally as he was starting to dry out being out for so long. Not only that, his hip was starting to fucking hurt being propped up on his side on this hard stone surface. But as he looked down at the human—his beautiful green eyes were red rimmed as he was lulled to sleep clinging against his chest—he guessed he could survive a little bit longer. He smiled as he curled his tail around his human as he hunkered down, his nose pressed into the soft, green-tinted curls. He sighed in contentment.

Chapter Text

Katsuki swished his tail as he followed through his circle.

“Come, Deku,” he called, as he tried to coax the trembling human into the water. 

It had been several days since the discovery of Deku’s fear and he had been trying to get him in the water every day since! How the hell did Deku expect to get over his fear of water if he never gets into the water? Stupid human. Maybe they didn’t have brains between their ears if they can’t even figure that much out. Actually, that would explain a lot if it’s just a bunch of blubber up there from the seemingly limitless amount of food they have. He’s still not over this refrigerator and how much food it could preserve for later consumption.

Deku looked over to him, a nervous twitch of his lips. His hand rested above his unclothed chest as he looked between Katsuki and the water. 

Katsuki huffed. He dipped his head below the water to hide flushed scales and cursed the thrumming of his heart. He didn’t understand humans and their mind games. It was fucking normal not to wear clothes with human writing over one’s chest! He is used to seeing humans like this all the time, but Deku— the asshole flirt he was— somehow made it a big deal! It was madding. He’s made the mundane into something confusingly distracting just by virtue of not showing it off.

Stupid fucking Deku and his stupid fucking built as fuck body. He knew it was easy to forget just how strong his human was with his tiny frame, pup-like face, and all-around innocent act. But somehow that just added to his… nope. Fuck. Nope. Stop thinking about that and think about how weird his fucking feet are. Don’t even think about how hot the rest of him was.

Suddenly, the human slapped the sides of his face with such force it left red marks on his freckled cheeks. “Okay!” He yelled before he took the first step into the water at the “ stairs” . Stupid name. 

Katsuki’s eyes widen as he watches the human take one, painfully slow, step at a time deeper into the water. He glided closer, careful not to move too suddenly and accidentally startle the man. He stopped when he was a tail’s length away and watched the human as he held onto the metal pole for dear life.

Large green eyes looked up to him, anxiety evident in his pursed lips.

Katsuki pouted. With the smallest movement possible, he lifted his head from the water. “I here, Deku,” he said evenly, but he didn’t move to close the distance. He couldn’t. He was here, he wouldn’t let anything happen to him, but he wasn’t going to push this further than he was ready. He needed Deku to trust him if they were ever going to plan to get anywhere with these lessons. It was the most basic skill taught to young Mer as they come to age, trust your pod mates to watch your back; albeit for him, it was more or less beat into his skull by the old sea hag.

It was a pain in the ass taking it at Deku’s slow pace to even get to step one, but he had to be patient. He couldn’t pressure him; he couldn’t force him to pick up his fucking pace or he would risk losing him to the fear for good. He could actually become afraid of him this time.

He lowered himself back into the water but kept his eyes on Deku as his mind wandered back to that moment Deku ran terrified from the room.

Katsuki’s wounds stung, but his mind couldn’t keep up. Every time he blinked he could see that look on Deku’s face: his eyes wide with fear as he looked at him. He honestly wished it was anger reflecting back at him, he would know how to deal with that since he was a bit of an expert with that particular emotion. But no, his pale face held only fear.

Fear of… him?

Just the thought hurt like a shark bite to the chest and it was pissing him off the more he thought of it. How dare he, that human fucking man make him… mildly tolerate his presence like that and then stiffen up like petrified coral before fleeing. Katsuki started pacing the small length of the pool as the thoughts started coming in quick succession. Was Deku getting cold fins about their courting and he was too much of a minnow to admit it? Did he want to break it off because he was afraid?

Fuck that! He would rip his damn throat out if Deku thought he could just play with him like another one of his stupid human games before getting bored of him and tossing him aside.

But as his blood boiled and his chest continued to ache, his mind settled and started poking holes in that theory. If Deku was just going to break it off with him, why did he JUST present him with a bed? That didn’t make any sense for him to put in all the effort to prepare this place for him just to up and reject him. Besides, if Deku was ever going to be afraid of him, it wouldn’t have been just now from him being pulled into the water. That was nothing like their fight for dominance. In comparison to when his life was literally between his teeth to when he was just fucking around playing, it was night and day. He didn’t show a hint of apprehension, he didn’t even seem to mind he has been marking his skin with his marks. Just moments before, he was cheering happily for him with a smile that Katsuki didn’t want to lose.

No. This wasn’t him, right? There had to be something else he was afraid of, that was the only solution. It couldn’t just be wishful thinking.

The speed? Maybe he doesn’t like to go fast? No, he has seen the human jump around faster than before. Maybe it was just the surprise that freaked him out and now he was just embarrassed about how much he overreacted. That could be… but it doesn’t feel right either, he has caught  Deku off guard with surprise attacks before, but this time he was actually afraid, not just startled. He ran down all the possibilities before quickly writing each of them off until there was only one, impossible element left.

He was afraid of the water. 

But that would be so stupid, it was impossible, wouldn’t it be? How could someone be afraid of the lifeblood of the planet? It was insanity! It literally was the thing that kept them BOTH alive as well as all the other creatures of this planet, right? He has SEEN Deku interact with water many times before as well. He’s even seen him completely wet before and he didn’t have a problem then either. So it couldn’t be the water, right?

And it couldn’t be that he couldn’t swim (even though in this shallow water it wouldn’t really be considered swimming), right? Not only did he know humans, in general, could swim (poorly) he’s seen Deku himself swimming before. Well, swimming would be too strong of a word for what Deku was doing that day, maybe more like flailing around like a dying baby seal before sinking like a rock. 

Katsuki stopped dead in the water. He slowly sank to the bottom of the deep end of his bed. 

The trauma of nearly dying at such a young age. Of all of his theories up to this point, this one seemed the most sound. And for the first time in days, his mind floats back to the long-tailed dunce face of a pod mate, Denki. 

As a pup, that idiot got his tail caught in some kelp, normally no big deal. Just calmly remove it or call someone to help you remove it and move on with your life. Denki did the opposite. He panicked and flipped the fuck out. By the time the screaming caught his and the other young mers attentions, he was completely covered from head to tail in kelp. They tried to get him out, but the kelp was covering his gills making it hard for him to breathe so he struggled against them. Even now, Katsuki distinctly remembers the shrill trills of the distressed young mer convinced he was going to die. 

In the end, he got out, of course. His old hag was nearby and when she heard the commotion, she rushed over and was able to cut Denki out of the kelps hold. But even to this day, as a fully grown mer fluttering his scales for potential mates, he’s still hesitant to even swim past a kelp forest let alone enter one. 

Was Deku like that, but with all of the water? 

Even as a pup he knew humans didn’t have gills to help them breathe under the water; they only had the breath of their lungs. If the oldest of songs are to be believed, they traded away that part of themselves to be given superior lungs and the ability to walk on land. Sure, any Mer could breathe air or water, but none could survive on only one or the other. But humans didn’t have the luxury. Human’s drown in the engulfing love of the ocean’s cool embrace. 

That day, Deku nearly had his life snuffed out before it barely even began. Only to suffer a fate he could only imagine as being almost worse than death, a life afraid of the water. 

Katsuki felt his stomach drop. Deku wasn’t afraid of him, but he was because of… shit! He had to talk to Deku, NOW! 

Katsuki shot to the surface, annoyed to see that Deku was still not in sight. He mentally cursed before kicking off the edge of the water and started to pull himself out. 

He was right with his theory, of course, but he will admit it was a relief to hear it directly from Deku. He promised Deku he would help him get over his fear, but he honestly thought it would be easier than this. 

Katsuki smirked as he watched Deku’s second foot join the first on the bottom of the pool. The human looked up to him with a small, forced smile while he still hung onto the metal pole for dear life. 

But then again, any gestures hoping to follow (top) Deku’s courting display would be a monumental demonstration of commitment. And he will never back down from a challenge such as this. He’ll not only get Deku over his fear of the water, but he’ll teach him to be the best fucking swimmer the humans have ever seen. 

Katsuki chuckled causing bubbles to rise to the surface. Deku wouldn’t know what hit him by the time he’s done with him!

He cockily swam over to the trembling human. “Relax,” he said as he saw Deku stiffen at his approach. He pulled his tail around so he sat on the bed’s bottom and offered his hands to the human. “Hands.” 

Deku looked to Katsuki’s hands. 

“It okay, Deku,” Katsuki said with a roll of his eyes. 

Deku gives a small nod. One at a time, he ripped his hands from the pole and put them heavily into Katsuki’s hands. His grip was like a crab clamming their claws around him and even though he was sure he hasn’t seen them in the water yet, they were wet. 

“Good, Deku,” he complimented. He slowly uncurled his tail—ignoring the small ache of his wounds—and started to lead the human towards the center of the shallow end. He kept his eyes focused like a barracuda stalking his prey to the human’s face, looking to see if it ever becomes too much for him. He stopped when he reached his destination. He let his tail once again curling it up so he could rest part of the way out of the water, without letting go of Deku’s hands (not that he had much of a choice in that matter). 

“Kacchan?” His lips quiver. 

“Relax,” Katsuki said. He brought their hands to his chest and took a deep breath from the air. The first lesson was simple, Deku needed to be able to relax in water. This shouldn’t be too bad since the water was currently only lapping just above the waist of his short pants… oh shit they were close.

Katsuki eyes spun as he realized his proximity to Deku’s unclothed upper half. His chest was toned with defined abs that made him just want to touch them—oh shit, he was touching them. Stop that. Stop that. He thought as he pulled their hands back to center, and pretended that he was just stretching and accidently bumped into him. Yes, that’s what happened. No weird shit. 

But his eyes didn’t give up as he noticed the hair that grew on his stomach, enticing him downward towards the beast dick Deku is hiding. The human tried to pull some shit the first night with that freakish thing… but he was kind of, maybe morbidly, curious what the human looked like down there when his dick wasn’t out. 

His eyes widen as he realized what he was thinking. He felt all of his scales flush at once and his once nearly black scales become increasingly more saturated with orange.

What the fuck was wrong with him?! 

Shit, he wasn’t just sizing him up. No he was just… okay, he didn’t know what the fuck he was doing but it was definatly not THAT! 

But that didn’t matter because Deku is going to notice and THINK that. He’s going to think he’s starting to win him over and he, Katsuki Bakugou, is actually starting to look at him as a serious mate candidate. 

Fuck, fuck, fuck, fuck, FUCK! 

Slowly, Katsuki eased his eyes up to his doom, but he was surprised when he noticed there was no smug look on the human’s face. Hell, he didn’t even seem nervous as his eyes were locked onto his chest, or well, more specifically his gills. Because of the way he was sitting, his chest where his gills were located were only partially submerged. Before he annoyingly became aware of them and started thinking about it; they  fluttered slightly as the opened and shut depending on where the water surrounded. 

“Deku?” Katsuki asked; his brows furrowed. 

Deku blinked back to attention and looked at Katsuki. A blush quickly spread across his face to his ears. “Sorry, Kacchan. I ~~~ ~~~~ looking ~~ ~~~~,” he stopped and pointed—still without removing his hand from Katsuki’s—to his gills, “ gills. ” 

A wave of relief washed over him. Deku didn’t notice. He didn’t have to worry about— wait! His eyes shot up to scan the human.

He wasn’t freaking himself out.

An idea popped into Katsuki’s mind in how he could possibly progress to the next step far quicker than previously thought possible. 

“Deku,” he said quickly before his green haired idiot could notice. 

Deku jumped, “Kacchan?” 

“Deku looking… gills?” 

His cheek flush deeper.“S-Sorry Kacchan, I—”

“Deku want looking close?” He asked with a growing smirk. 

“I…” Deku’s lips pull together and he gives a small nod.


“Knees?” Deku stuttered, confusion pulled at his brows.

Katsuki nodded. “Deku, down knees.”

Green eyes widened as his mouth parted. He started shaking his head as his hand started to pull away. “K-Kacchan, I—”

“No,” Katsuki growled sharply to bring Deku out of his downhill mind set before it began. He gripped the human’s callused hands before murmuring in a much calmer tone words of comfort. “It okay, Deku. Head above water. No afraid. No drowning. I here, no drowning,” he repeated, finally getting Deku to look back at him. “You looking gills, yes? You looking close? Down knees looking close.”

Deku closed his eyes as he bite his lower lip. 

“Relax Deku. It okay,” he said as he uncoiled his tail just a bit so he could wrap it around Deku’s legs. 

The second his tail touched him, Deku’s eyes shot open as he nearly jumped straight out of the water. In the next second, as he realized what it was, he put one of his hands, and subsequently Kacchan’s hand, to his chest and took a deep, but shaky breath. 

Katsuki could feel the furious beating through this chiseled chest. Not the time for that, he thought as he banished the undesirable thoughts from his head. 

P-Promise ?” Deku asked. 

Katsuki wasn’t sure of that word’s meaning, well, not for sure at least. But he nodded and repeated. “P-Promise.” 

Deku wobbled on his feet before he awkwardly shifted his body to kneel in the water. Their interlocked hands went under the water first; the cool water feeling refreshing as it weaved its way around the iron locked palms. Next was his torso, breathing in quick gulps. His eyes were scrunched closed as his knees floated onto his tail; now only his head and half of his neck was above the water. 

“Deku, eyes.”

He shook his head.

“Deku,” he said again with a click as he glided their hands over his gills. “Looking gills, Deku.” 

Slowly, very slowly Deku cracked open one eye. 

Katsuki gave the human his reward and manually fluttered his gills for Deku to see. 

Deku’s other eye slowly opened. His breathing was still far too quick for being stationary, and his pupils were visibly dilated with fear. But it seemed to grab his attention, at least, just a little. 

Katsuki took a breath of air, slowly and steadily. He then did the same, but with his gills. The motion was a lot subtler than the first as the only thing moving the second time were four slits, two on either side of his chest. 

Deku’s eyes were sparkling as he watched Katsuki repeat the process. 

Katsuki smirked. His brilliant plan worked. He was able to get Deku to this point in a fraction of the time it took him to get in the water. If he continues like this, it will take no time before—and that was a finger in his gill.

He inhaled sharply.