Katsuki had impeccable senses.
To be expected of one of the top heros, a top UA graduate, and peak alpha.
Katsuki could sense things about the people he was around, and he knew to trust those instincts. He’d survived more battles, beat more villains, and saved the day too many times to count to ignore what his senses were telling him.
Katsuki knew something was off about Izuku.
There was something that smelled different about the nerdy kid who lived next to his parents home. They had met several times, but Katsuki didn't spend a lot of time with the other kid, he was, after all, just a kid. Katsuki had better things to do with his time than deal with a little brat.
He did hear a lot about him though, as his mother was close to Izuku's mother. And, despite telling his mom he didn't fucking care about that stupid kid, his mom insisted on telling him every little fucking detail about him. He wasn’t sure if it was some sort of new tortue the hag had some up with, or her way of trying to get them to be friends.
No matter the reason, and no matter how hard Katsuki tried to ignore his mother, ignore the asinine details that poured from her mouth, he couldn’t help be learn more about his neighbour.
The kid, with no quirk, was trying to get into UA, his alma mater, the school for heroes. It made Katsuki scoff.
UA is for heroes, not for shitty quirkless brats.
As if that little kid, that Deku , could get in.
And then his mom said that the kid had presented as a beta, and, with that, Katsuki knew that even gen ed wouldn't accept that Deku. Most of the heroes were alphas, naturally. And some omegas, while rare, were considered highly sought after assets, as they often were in possession of the more caring and comforting quirks required for rescue work. Betas....well. Someone needed to do all the other jobs, right?
And quirkless at that. Stupid Deku didn't stand a chance.
Katsuki’s senses, they were never wrong.
Something was off about Deku. He didn't smell right. Not like a beta, but not like anything else. Katsuki couldn't place it.
During the last family dinner, the Midoryia's had joined them, well, at least Inko and Izuku had. Katsuki had never met Hisashi, as he was always elsewhere, somewhere overseas, leaving his beta family alone.
That dinner had been enlightening. And infuriating, in the murder-inducing kind of way.
Katsuki tried to go for dinner at his parents once a week, but it had been several since his last visit. He’d been ass deep in some undercover work and hadn’t been able to make it. And, now that that pile of garbage assignment was done, he’d come home for a decent dinner, only to find this fresh hell.
A fresh hell that had Katsuki on edge, senses revved up, but for what?
That smell. Just...something about it was enticing, intoxicating. Katsuki couldn't figure it out, why some useless piece of shit Deku would smell like...something he wanted. But there was another smell there too, something acridic on the tip of his tongue, burning.
In addition to that goddamn smell, he had also learned that, despite presenting as a beta, that nerd was still planning on going to UA. Apparently, he had just started training at the beach, doing exercise or something. Katsuki scoffed at the delusional kid, but...
But, he had been training consistently and successfully at that. He had changed his diet, and was starting to get muscle, become lean and built.
Had been training for a few months and had already started showing results.
Both the women were gushing over the discipline and resolve of Izuku’s new regime, praising his dedication to getting into UA.
Katsuki thought they were both fucking idiots to encourage something that would obviously end in complete failure.
He was mid-bite of dinner when his mom turned towards him, face bright and downright evil.
“Katsuki, you should train Izuku some time, show him some things.” Mitsuki said, as she and Inko discussed Izuku's training regime.
Katsuki shot his mother a look, pure venom. That damn hag knew Katsuki had better things to do. Literally anything was better than working out with some barely teenage quirkless idiot. Add in the constant hero worship the kid had, and it was unbearable.
Working out with that nerd would give him the chance to figure out what the goddamn smell was. Was it something in his clothes? Maybe producing more sweat and therefore more pheromones would help Katsuki figure this goddamn smell out.
Besides, now that Mitsuki had mentioned it, both Inko and Izuku had perked up, eyeing him, seeing what he would say, both with hopeful looks on their faces.
He cleared his throat “Uh yea. If you want, we could, like fucking workout or something. Go to the gym. There's a private one that I go to, so.”
He was only doing this favour for selfish reasons, to figure out that goddamn scent. That said, he sure as shit didn't want anyone to see him working out with some teen. Luckily, his agency allowed some heroes access to one of the smaller, private gyms. Due to his quirk, Katsuki was one of those heroes.
It paid to be an explosive asshole sometimes.
Bright green eyes lit up “Really Kacchan? I'd love that! Getting to train with one of the top heroes is such a unique opportunity and….”
He rattled off about how amazing the experience would be for him, and Katsuki tuned him out.
His mother shot him a smirk, the old hag gleeful. It was like she had planned this or something.
Probably had, knowing her.
They agreed to workout the following Friday, after Deku got home from school. He would be dropped off at the agency, where Katsuki would be waiting.
Inko would be at work, and felt relieved knowing her baby boy would be in good hands.
Katsuki wasn’t sure about that, but wasn’t going to be the one to argue with her.
The fated day finally arrived, and Katsuki paced the entrance way of his agency, waiting for his mom and the kid. He already had his gym clothes, black tank and burnt orange sweatpants, ready to put on, as well as a few bottles of water, protein bars, and some fruit.
If he was going to show some newbie about working out, he wasn’t going to half ass it.
Katsuki was a perfectionist, in everything he did.
Soon enough, Katsuki saw those bright green curls entering the building, a noticeable skip in the kids step, the black middle school outfit standing out like a fucking beacon. He watched as Deku looked around in awe at the agency, security already side-eyeing the kid, before noticing Katsuki where he leaned against a pillar.
“Kacchan!” he squeeked, hurrying over to the blond. He nearly tripped in his haste, but his smile didn’t waiver. Bright green eyes, glowing with excitement cheeks flushed, sprinkled with freckles stared up at Katsuki, and he was gut-punched by his senses.
It was as if he had forgotten how…. off ….Deku had smelled. How that smell did things to him, and his inner alpha, and he just...didn’t understand.
He sighed. It was only a day, and he could avoid that nerd again. Avoid that scent, and the confusion that came with it. Katsuki was a simple man, and hated grey areas, or anything that didn’t fit into his definition of the world. No. Better to do this one thing with this kid, get it over with.
The whole point of this little outing was to figure out that fucking smell, but, it may have been waste of time. He sighed again.
“Let’s get you checked in, then.” He said, before turning on his heel and marching towards the frontdesk.
As much as it pained him to admit, Katsuki was a little impressed with the little nerd. No matter what exercises Katsuki threw at the kid, he did them without complaint. No matter how hard, how heavy, or intense, Deku completed everything Katsuki told him to. Sure, he asked questions, but they were intelligent and smart questions, ones that more pros should ask.
It was a long session, with a break halfway through to eat the fruit Katsuki had brought. The kid had brought food, but not enough for an additional snack, so Katsuki threw a banana and pixie sticks to him, while he ate his own.
Those green eyes looked up at him, as sweat dripped down his face, with complete awe and determination.
Katsuki looked away, the mirrors showing the back of Deku, shirt sweat-soaked, green hair even more curly, and his disgruntled face, streaked with sweat, blond hair wilted.
There were worse workout partners to have. Even if Deku was quirkless.
“Sauna? I’ve only used the ones in the bathhouses.”
Katsuki grunted his response “This is pretty much the same, just less people and smaller.”
“Okay, but why?”
They were both sweat soaked and exhausted, protein shakes consumed, as they disrobed in the lockers.
Deku had gone into the changerooms, leaving Katsuki at his locker, leaving his dirty gym clothes in the hamper provided for staff, and a towel wrapped around his waist. He was leaning against the locker as he waited.
“Does your body hurt? Muscles already sore?”
“Well, yes, but-”
Katsuki talked over him “The heat and moisture help open your circulation and shit. Means faster recovery because of increased blood flow.”
“And you managed to keep up with me. Your body will fucking hate you tomorrow. Better to reduce the pain now, or whatever.”
The change room door opened, revealing a flushed, freckled Deku, skin still sweaty, a huge grin on his face.
“That’s really smart, Kacchan! Thanks for looking out for me.”
Katsuki snorted as he pushed himself off the locker, and moved towards the large wooden door that led to the sauna.
“Whatever. Let’s go.”
He held the door open, ushering Deku in, before setting the heat and the timer, and grabbing the water for the rocks.
Katsuki normally thought through decisions. He had great instincts, that had never led him wrong before. He was a Alpha alpha, for fucks sake.
So where had this all gone so fucking wrong?
That smell. It was driving Katsuki insane.
Why hadn’t he seen it coming? That scent….was different now. Something had changed about it, which was impossible.
Yet here they were.
Deku’s scent had changed, and Katsuki was beginning to release his own pheromones, as his senses sharpened, on alert.
As the minutes ticked by, Deku began to look more and more flustered. He was squirming in his seat, green eyes darting over to where Katsuki sat, red eyes boring into the teen.
“Um, Kacchan? Is...is something wrong?”
Katsuki shifted, leaning forward, elbows on his knees, eyes never breaking contact. “You tell me.”
Hands wrapped around green hair, face red and flushed. “I..I don’t know wh-”
“Stop. Just, fucking stop. You know exactly what I’m talking about.” Katsuki growled. He couldn’t stop himself, couldn’t reign it in.
He ran a hand through his hair, taking a deep breath in.
He growled again, and red eyes bore into green. The air between them was electric, hot.
“Your scent, Deku.”
That charge was overwhelming, every nerve in Katsuki’s body ready to snap. He was ready. For what, he didn’t know yet, but it didn’t matter.
“Please….just...can you lay off a second?” Deku’s voice was quiet, tense. Pained.
Katsuki growled, reigning his alpha in. At least, a little.
He watched as Deku took a deep breath in, face still flushed, burning.
“It’s...I…” he chewed his lip, darting glances at Katsuki, who hadn’t moved.
“Spit it out.” Voice low, and rough.
“You’re not a…” Katsuki repeated, as realization dawned on him.
"Blockers, right?” At a nod, he continued. “But not very good ones, I’m guessing.”
Katsuki ran his hands down his face. Okay. So that was one problem solved.
And, given the state of his alpha, one more created. He couldn’t stop his alpha from releasing his scent, his power. Katsuki’s alpha wanted this little omega, wanted to mark him, claim him .
This wasn’t the first omega he’s met of course, but it was the first one that called to Katsuki, the first that smelled like that .
Like home. Like safety. Like want .
He moved closer to the little green haired omega, whose eyes watched him.
He didn’t respond, moving closer and closer, his face inches away from those freckled cheeks. He curved his cheek along those freckles, a ghost of a touch, burying his nose in that neck, breathing in that sweet scent, a low growl.
The body beneath him responded, scent a mix of fear, and longing. And slick. Even from here, Katsuki could tell that the boy was prepping for him, preparing for the alpha.
Katsuki’s dick twitched. He took another breath in, swiping his tongue along that hot slick skin, mouthing the scent gland.
“-wait….Kacchan….please…” Deku’s voice was soft, broken. Breathy. The scent was increasing, clouding Katsuki’s head.
Katsuki sat on the bench, hard, pulling Deku on top of him, legs straddled across his lap. His dick begged to be touched, to be fondled, to be sheathed within that slick that smelled so fucking good.
He pulled Deku down, pressing their lips together, one hand reaching around to the small of the boys back, fingers massaging, while the other hand wound through that riot of hair.
It took a few moments, but, eventually, those hot lips responded, sliding against Katsuki’s, slick, searing against his own. Katsuki licked those lips, mouth opening in a shocked response, breaths panting into Katsuki as he licked into that mouth, savouring that taste against his tongue. Small moans greeted him as he sucked on that small, pert tongue.
The smell of omegan slick and alpha permeated the sauna, their panting breath, punctuated by small moans the only sounds.
The hand massaging Deku’s back moved downwards, strong hand moving across a plush ass cheek, fingers close to where they really wanted to be, if that damned towel wasn’t in the way. .
Lips still connected, Katsuki moved them both, moving his hand to remove both their towels, grinning when Deku gasped as their cocks touched. As he settled them back on the bench, he shifted Deku so that the little cock rested against his, moving ever so gently as they breathed in, delicious, teasing.
Katsuki could feel the slick from the little omegan dripping down from his ass, on to Katsuki’s thigh.
He growled, plunging his tongue into Deku’s mouth, licking, sucking. Biting. One hand was back in that hair, gripping, pulling. Holding that small face still as he sucked and bit and licked. The other hand was gripped around a plump ass, fingertips gentle as they caressed between the cheeks, inching inwards.
A small, but strong hand, was in his own hair, fingers tight around the blond locks. The other was slowly making its way across his pec, fingers slow, shaking.
Katsuki moved his head, mouth seeking out that needy scent at that plump neck, skin soft and juicy as he sunk his teeth in, not quite drawing blood, but not gently either.
A cry sounded above him, as Katsuki licked the already blood filled skin. He hadn’t broken the skin, hadn’t claimed him as a mate, but it was close.
Katsuki restrained himself, moving his wandering mouth towards dusty pert nipples, sucking them in, as Izuku moaned above him, those cries spurning him on.
As he sucked hard on one nipple, his fingers had found the slick soaked hole, swirling his fingers around the soft skin, hot and wet, before slipping one in.
It nearly sucked his finger in, needy, as the body on him shuddered.
“Please….more...Kac-” came the panting voice, his omegan body coming undone, more slick spreading across Katsuki’s prodding fingers.
He grinned as he nipped at Izuku’s chest.
“My fucking pleasure” he growled in response, inserting a second finger.
Izuku moaned as Katsuki thrust those fingers in, rubbing at the hot wet flesh, searching for that spot, that sweet spot.
As he thrust into that slick heat, small hands, shaking ever so gently, reached down, towards his dick, gentle at first, then more confident as Katsuki moaned his encouragement. Those small hands wrapped around his dick, pulling, stroking, as he moaned his own excitement above him, hips rocking into Katsuki’s fingers, as he added a third.
A loud cry let Katsuki know he found the spot he was looking for. He made sure to rub against it as he continued to thrust in, loosening the hole, slick dripping down his fingers, his hand.
“You like that, huh? Like me in your ass?”
“hngg….Please……” The hands on his dick were losing their rhythm, and Katsuki knew Izuku was close.
He wrapped a hand around Izuku’s cock, leading it to his, pressing them together and be began to stroke. Long, sure thrusts, fingers deep within that hot flesh, that squeezed around his fingers.
Izuku cried out, ass clamping down, as slick flowed onto Katsuki, and hot white ropes of cum splattered across Katsuki’s chest.
Izuku panted, green eyes looking down at Katsuki, both of their dicks still hard.
“-pleas...more…” Izuku could barely speak, breath heavy against Katsuki, body trembling on his.
Katsuki grinned, before reaching up and claiming those lips with his own.
He removed his fingers from Izuku, and shifted them on the bench, his lips and teeth and tongue, biting and exploring.
Izuku was rocking his hips against Katsuki as he positioned them, his slick dripping across his thighs and dick, as he lined himself up.
The head of his cock was just at Izuku’s opening, stretching the skin, as Izuku leaned forward, mouth open, and teeth sinking into Katsuki’s neck.
“Wha-” He was cut off as he felt those teeth pierce his skin, and knew that blood was pooling in Izuku’s mouth.
Fucking little omega had claimed him!
Katsuki couldn’t stop himself, not now. He moaned, loud and long, as he sunk himself into Izuku, not stopping, or even slowing until he’d bottomed out.
Izuku was still latched onto his neck, whimpering in Katsuki’s ear.
He stayed like that a few moments, the heat around his dick sucking him in, pulsating, and so so wet.
Another wave of pleasure hit him as Izuku sucked at the wound he’d caused.
He grabbed Izuku’s hair, wrenching his neck to the side, and sunk his own teeth into that soft, breakable skin, the tang of iron dancing across his tongue.
Above him, Izuku keened, rocking his hips across Katsuki’s cock, ass dripping as he fucked himself on Katsuki.
Not moving his mouth, Katsuki began to thrust into Izuku in earnest, flesh against flesh, as Izuku cried out, scenting the room with pleasure and want and need.
As Katsuki thrust into that heat, that wet heat, he sucked at the wound, his mark, his claim, the sweet pleasure of a mate sending waves crashing across his body.
“You’re mine, Deku. Always mine.” Each word punctuated with grunts as he thrust into that heat, that warm, wet, welcoming heat.
Katsuki thrust harder, reaching a hand down to fondle that little cock, so red and weeping with precum, begging for release.
Katsuki would happily oblige. Would give his little omega as many orgasms as he needed, as he wanted.
It didn’t take long before the boy under him fell apart, cries echoing in the hot, wet room, as white hot ropes shot across his stomach, ass spasming around Katsuki, squeezing his cock.
One, two, three more strokes, and Katsuki was done, grunting as he released, filling Izuku with hot cum.
Hot slick spread across Katsuki’s cock, spilling between the seams, as he pulled Izuku closer, plunging his tongue into Deku’s mouth.
“Mine” he growled, hand gripped around Deku’s chin.
Katsuki could tell the second Izuku felt it, green eyes widening, cheeks flushing, in pleasure of embarrassment, Katsuki didn’t care.
“Mine” he hissed again, as the piss he was releasing inside Izuku spilled out, and around them, hot against their already hot skin.
“Hngg….Kac-” Izuku moaned, another small burst of hot white splattering between them.
Katsuki caught the limp boy, who collapsed across his hot, slick body. He was exhausted, hell, they both were. Exhausted and overheated, the sauna still whirring its heat, and steam. Swirling their scents with the hot wetness.
Without pulling out, he wrapped his arms around the pliant boy, planting a kiss on his forehead before standing up.
They left the sauna, and Katsuki moved them to the showers turning the water on, before sitting them down on the floor, the water cooling their skin.
A wave of satisfaction hit Katsuki as watched Izuku’s ass empty like a fountain of piss and cum and slick.
One day, he would be upset about that lost cum, and piss. One day, Izuku would be plugged up with all those fluids, plugged up and bred. But, not yet.
“How are you feeling, Izu?”
A small voice answered him “Tired.”
Katsuki smiled, hand brushing along wet hair. “Okay. Just relax then.”
A small sound of acquiescence was the only reply.
Katsuki moved them closer to his shower things and got to work. He started with Izuku’s hair, using his nails to massage the scalp, fingers running the suds through curls, detangling as he went. Then he did the same with conditioner, smoothing the locks as he rinsed it out.
He moved to face wash next, fingers swiping across cheeks, thumbs caressing pert, still swollen lips. Katsuki leaned down to kiss those lips, a small smile on Izuku’s face when he pulled away.
Next, came body wash, administered with a gently scrub pad, as Katsuki cleaned every surface, every crevice. He was gentle, seeing the small bruises already forming on pale skin, freckles blending in with the redness. Katsuki wanted to kiss each bruise, each freckle, but, his omega was tired and his alpha knew better than to try his luck.
As the suds swirled down the drain, Katsuki quickly washed his own hair and body, leaving Izuku propped against the wall, drained and exhausted. He finished quickly, turning the water off. He wrapped Izuku in a new fluffy towel and carried him to their lockers, depositing the nearly-sleeping boy on the bench.
Katsuki dried and dressed Izuku first, then followed suit. Ran a comb those those thick curls, as the boy keened with pleasure, nearly purring his pleasure.
The alpha in Katsuki preened at that sound, knowing he was pleasing his mate.
He hoisted both of their bags on his back, picked Izuku up bridal style, and marched them to the adjacent parking lot, thankfully seeing no one as they went.
Katsuki, king asshole and alpha, carrying a boy in his arm would be suspicious, and he didn’t need anyone getting in their way.
His little omega needed rest, and anyone who came between that was going to die painfully.
He spoke gently, as he told Izuku what they were doing as he loaded them and their stuff into the car.
“We’re gonna go to my place, and you can rest, okay? I’ll make food too. If I remember right, you like katsudon, yea? Want some of that?”
“Mmmm….please….” A soft, pleased scent filled the car.
The alpha preened at the compliment, pleased with his care.
The drive was quiet, Izuku sleeping on the seat beside him. The soft scent that emanated from Izuku was calming, and felt like home. At least that all made sense now.
Katsuki had found his omega.