Being the Dragon King, Katsuki has seen, fought, allied himself with, and helped to raise hundreds upon hundreds of dragons. Although still a teenager he has arguably had more experience in his ten years living with the dragons than the average man three times his age has had, period. Where most men might work in a field all day and then spend their nights getting plastered at a tavern, Katsuki spent all of his days keeping the peace between nearly thirty different types of dragons that called the mountains their home. He spent many evenings doing this, too. And was often woken in the middle of the night to settle petty squabbles between the beasts. Any fool who said that wasn’t dangerous had clearly never had to step between an enraged dragon and whatever foolish one had decided to try stealing its kill.
Again, Katsuki had spent a little more than a decade in the mountains with the beasts. Ever since he had wandered too far from home and gotten lost at the age of five. He had nearly wept himself to sleep that night, knowing that he was going to die either from the cold or from some animal that lurked in the darkness and decided to make a quick meal out of him. It was by some great fortune that a kindly dragon who had just become a mother found him first. As some new mother animals have been known to do, she took sympathy with the child she had found and raised him. As he grew, he began to spread his wings in a more metaphorical sense than his draconic siblings and began to discover and learn about other types of dragons. He grew wiser and stronger with everyday living out there in the wilds.
When he had successfully defeated the former “king”, a huge fire-breathing dragon with charcoal black scales and eyes the color of blood, at the age of fourteen and with his bare hands he was bestowed with a gift rarely seen or even heard about in folktales by humans: draconic magic. Suiting both his dragon family’s lineage as well as the king he had just humbled, the magic was powerful and explosive, and with some ingenuity extremely versatile. And it opened up an even greater number of doors for him. With it, he even learned to “fly” like his siblings had many years before him.
Having been around dragons for so long, Katsuki knew better than to think he knew everything about them. In fact he was fascinated by the beasts and learned something new about them nearly every week. That said, he did often find himself thinking that he couldn’t really be surprised by them anymore. Big dragons, small dragons, fierce dragons, nurturing dragons. Dragons that breathed fire, ice, poison, and even lightning. Dragons that flew in the skies, dragons that swam in the seas, dragons that resided in the ice-caped peaks, and even dragons that could burrow through the earth. He was certain that he had seen every type there was to see.
Which is why he was actually shocked when he stumbled across a strange egg early one morning while he had been out hunting. It was too large to belong to anything but a dragon, but it was on the small side; only a bit larger than his head, actually. But he had never seen an egg so vividly green before. It was like an emerald. The wyverns that usually made the forest he was hunting in their stomping grounds had much darker eggs, ones that could be more easily camouflaged in the underbrush, and were nearly large enough that Katsuki could fit inside of if he were to curl into the fetal position. Thoroughly curious, he decided to take the egg to his mother.
She was hesitant to accept the egg at first. She too did not know from where it came or to whom it might belong. In addition to that she wasn’t currently caring for a clutch of eggs nor raising any young. She hadn’t done so since Katsuki defeated the former king and took his title. But he insisted and so she reluctantly took the egg into her care. Not knowing what sort of dragon it was meant that there was a chance the embryo would die well before it could hatch, but Katsuki’s mother had good instincts and he trusted her more than any other dragon to raise an unknown species.
Katsuki didn’t see his mother for a long while after that. She had taken the egg to a secluded part of their mountains in order to nest and hatch whatever came out. It wasn’t uncommon for dragons to seek solitude while raising their young, and she had done so herself a few times throughout Katsuki’s life. He knew that she would return either when the egg had rotted or when she could safely bring whatever came out of it home. So for several months Katsuki put the strange egg out of his mind and went on with his duties as king.
The cold of winter was nearly upon the mountains when Katsuki at last heard the familiar beating of his mother’s wings overhead. He craned his neck and shaded his eyes from the sun in order to catch sight of her flying over the mountains and towards the cave where he resided. Immensely curious about what came of the egg, he finished tending to the wounds of a tiny wyrm that had stupidly tried to steal a larger dragon’s dinner and then made his way to his cave.
His mother was waiting for him, something cradled between her front legs where she lay on the cold stone floor. She allowed Katsuki to approach and investigate what it was. And what he saw sucked the breath right out of him.
The creature was most certainly a dragon. There was no other way to really describe it. And yet, it was unlike any that Katsuki had ever seen. Teal scales covered the baby’s tiny body, with reds and blacks dotting its body like freckles. Oddly, the bottoms of its hind feet were bright red. Although small and pudgy it was already evident that it would later be lankier than most dragons. The wings upon its back were tiny compared to its body even for a baby, meaning there was a chance it would never fly. And strangest of all, there was a tiny mop of what could only be described as curly green hair on its head. Katsuki had seen dragons with feathers or fur before. But he had never seen one with only a tiny little patch on the head.
Katsuki instructed his mother to continue to raise the baby, and she of course complied.
The winter passed and Katsuki’s mother raised the strange creature where she normally brought up her young; in a little cave just down the mountain from where Katsuki’s was. He didn’t get to see her much during the cold months and didn’t see the strange dragon at all during that time. It wasn’t until spring came and flowers began to bloom that he was able to see how the dragon was developing.
It looked…almost human. It was indeed lanky and its wings were undersized for its body. It had some trouble crawling around on all fours due to the length and shape of its limbs, but it was doing a much better job than Katsuki would have been able to. And what’s more the curly hair upon its head had only grown thicker and longer. If he were to guess, its age probably would have been about the equivalent of a human four year old.
When it first spotted Katsuki it hurriedly hid behind their mother’s legs. She gently coaxed it out from behind her and Katsuki knelt down to make himself seem less threatening. The little dragon slowly crept toward him and sniffed his outstretched hand. Its big green eyes stared up at him curiously. It surely didn’t remember him at all. Katsuki inquired about what his mother thought about it. She told him that it was a male, and that she had never encountered a dragon like him before. She decided to let Katsuki name it whatever he liked, since he had discovered the egg.
Naming a dragon was a sacred privilege few ever got to be a part of. Parent dragons rarely chose a name on their own, instead asking a trusted ally to do it for them. Katsuki had named only a handful of dragons in his life, despite being the king for two years now and being the elder brother of about a dozen. Looking at those curious green eyes and teal body, Katsuki knew exactly what name he wanted to give it.
Since the time of the odd dragon’s naming, he became infatuated with Katsuki. Whenever he could he would follow behind him. This led to Katsuki having to drive him off on a number of occasions. He couldn’t have a juvenile dragon following him on hunts or into the territory of a mother dragon, or into a space where a dragon was rampaging and needed to be calmed. But the little dragon always came back to him. Izuku would watch with wonder in his eyes whenever Katsuki would use his magic, or drag home a fresh kill and begin to carve it…or when Katsuki would just sit around his cave being bored. It seemed that Izuku liked nothing more than to be near him and to be allowed to just…watch him.
It was kind of creepy, if Katsuki was honest.
By mid-summer Izuku had grown a lot. He was nearly up to Katsuki’s shoulders when he could be provoked up onto his hind legs. Which wasn’t difficult due to his build being similar to that of a human’s, but he was never very steady and only ever managed a few steps when he tried to imitate Katsuki.
In addition to having grown a lot, Izuku was beginning to display and hone his unique talents that set him apart from every dragon that Katsuki had ever known. First of all, Izuku could not breathe the elements like many other dragons. But often times when he played Katsuki could see green electric energy coursing through his body. It made Izuku both stronger and faster than he could be normally. In addition to that, black tendrils would sometimes seep out from Izuku’s body, though he appeared to have little control over them and they would vanish quickly after manifesting.
Now, while Katsuki had grown up surrounded by dragons and really didn’t like spending time in human civilizations, he wasn’t exactly a stranger to them. The energy and tendrils that Izuku displayed were weirdly similar to human magic. Augmenting one’s physical abilities and wielding ethereal tools were things that powerful wizards and sorcerers had been doing for centuries.
Perhaps that was why Izuku seemed to be so taken with Katsuki. Perhaps the dragon felt a sort of kinship with the human who wielded dragon magic when he was a dragon who for some reason wielded human magic. Katsuki really couldn’t say.
Speaking of saying things, though, there was one more thing that separated Izuku from any other dragon. Where Katsuki could speak the language of dragons, none could speak the languages of humans. The most they could do is have an innate understanding of what a human might be trying to get across to them, though those dragons were few and far between. Katsuki’s mother was one of such. Izuku, on the other hand, seemed to understand even actively try to speak in the human tongue that Katsuki knew. He couldn’t form words, but that didn’t stop him from mimicking tone and inflections of simple words and phrases by chuffing and trilling and making other noises.
Most impressive, however, was the fact that he could almost speak Katsuki’s name the way a human would. Almost.
“Kacchan!” Izuku would say in a trilling little voice whenever he wanted Katsuki’s attention.
The first time he did it Katsuki nearly shat himself.
That said, Izuku wasn’t particularly smart. He didn’t seem to have a lot of common sense and was prone to injury whenever he went out on his own. This resulted in him coming home bruised and bloodied and whimpering and whining “Kacchan! Kacchan!” until the human would sit him down and tend to his wounds while chiding him about taking care of himself. Izuku would hang his head and continue to whimper until he was all patched up. At which point he would stick himself to Katsuki’s side like glue for the rest of the day. Due to his recklessness, Katsuki had gotten into the habit of calling him “Dumb Izuku” and somewhere along the line that turned into “Deku”. Eventually, Izuku just kind of became Deku even when Katsuki wasn’t trying to insult or admonish him, and Izuku always responded to the nickname regardless.
When fall had nearly played itself out and winter was creeping upon them, Izuku had managed to hone his strange magic into a fine art. What he lacked in elemental breaths or even the ability to fly, he made up for in his nearly perfect hunting rate. What prey he couldn’t catch normally he could easily outrun with that green energy, and the prey that he still couldn’t catch, such as those that could fly away from him, he was able to snatch from the air with the tendrils and hold them down while he tore into them. Even Katsuki had to admit he was impressed by the oddly-shaped dragon being a better hunter than anything else he had ever seen. And for his part, Izuku was thrilled to now always be allowed to go hunting with the human Dragon King.
The colder nights saw dragons all over the mountains coming together regardless of if they were normally a solitary species. Winters were harsh on them as they were any creature, and most found it beneficial to sleep close to others of their own kind for warmth. It was also during this time that many found it good to breed, taking advantage of the proximity to attract a mate with less effort spent on finding others of their kind.
For his part, Katsuki had always spent the colder months alone. He had no interest in making the trek out to one of the nearest human villages in order to find one of his own kind to do it with. He was aware that it wouldn’t be difficult for him, as he had come to learn that he was very attractive by human standards and a number of women had offered him the prospect of sex in the past. He just had no interest in finding a mate or breeding in general. But when Izuku clambered his way up the mountain to his cave one evening Katsuki didn’t shoo him away. The odd dragon was a year old now and had reached sexual maturity some months ago, but didn’t have any of his own kind around either so even if he wanted to find a mate he couldn’t. It was a strange sort of kinship to have, but Katsuki found he didn’t really mind. Instead he let Izuku help himself to his meat reserves while he cooked something up for his own dinner.
That night when Katsuki crawled into his bed of furs Izuku invited himself along. For some reason, Katsuki let the dragon curl himself around Katsuki’s body for warmth while they slept.
The first month or so of winter Katsuki went about his usual daily life like normal. The only difference was that Izuku never left him alone. The dragon was always right at his side, cuddling up for warmth or just generally hanging about. They went hunting together, although with the cold there wasn’t a whole lot to be caught. Izuku’s big green eyes would watch with wonder and curiosity as Katsuki would do chores around his home as if the human’s very breathing was the most amazing thing in the world. A number of times the dragon would even try to assist him, reaching out with his very human-like forelegs, but he was too clumsy with what would be his hands to do much of anything more than grasp at things.
It became a bit much when Katsuki would have to shoo Izuku away so that he could take a piss or have even ten minutes of alone time at night if he needed it. But for the most part Katsuki found he didn’t really mind Izuku’s constant presence in his home.
That was, until one particular night that Izuku showed him something that quite frankly he had never really put much thought into. While Izuku’s overall build resembled that of a human he was still unmistakably a dragon. This was just a fact and one that Katsuki had come to know and accept a long time ago. The scales, the claws, the fangs, the wings. Yeah, he was a dragon. But what he hadn’t put any thought into was how a certain part of him was also very much dragon.
They had been lying in Katsuki’s bed and the human had been drifting off to sleep when the scaly lump snuggled beside him gave a small whimper and pressed closer to him. Not unusual, Izuku made lots of noises and so making one while getting more comfortable for sleep wasn’t anything to be alarmed about. But…he kept doing it. Little whines and a trill or two escaped the dragon and he kept squirming, sometimes closer, sometimes further away. Katsuki would’ve thought he was dreaming if he didn’t know both that Izuku was very much awake and also that Izuku’s dreams would have him twitching and not squirming.
A wet tongue against his neck had Katsuki swearing and he shot up in annoyance.
“Deku, what the fuck!? I’m trying to sleep! If you need to piss, go do it and come back to bed!” he shouted, throwing the blanket off the both of them and glaring down at the dragon.
And that’s when he saw it. Like any other dragon, Izuku didn’t have exposed genitals. So it was the first time that Katsuki had ever seen the pink fleshy organ hanging out of a slit between Izuku’s hind legs. Even though he had never seen it before, he could tell it wasn’t fully exposed yet. All he could see was a little head peeking out from where it had always been hidden away in secret.
A wave of disgust overcame Katsuki. This dumb, stupid dragon was horny! In his bed! But he wasn’t disgusted because of that. Oh no. That would be a normal person’s reaction to seeing dragon dick. No, instead he was disgusted with himself because the first thing that came to mind after registering that Izuku’s dick was hanging out and saying hello to him was that he wanted to make it come out more. What kind of sick curiosity was that?! Katsuki had seen more than a few dragon dicks in his time and quite frankly every single one made him never want to see another again in his life. And yet here he was, immensely curious about what Izuku’s would look like if it were coaxed out of its little hiding spot.
“Kacchan…” Izuku whined, eyes locked onto his.
Katsuki glanced up at him briefly before returning his gaze down to the dragon’s dick. He knew it was wrong, and he swore at himself for doing it, but the human just couldn’t help his morbid curiosity as he reached out towards Izuku’s subtle erection. He first slid a couple of fingers along either side of the head before pressing down, lightly stimulating the area around the slit. Izuku groaned and wriggled some more, repeating the human’s name. Katsuki kept at it, his touches growing bolder and in return the dragon’s dick began to emerge more and more. After a moment Katsuki threw his disgust aside and wrapped his hand around the exposed shaft and began to stroke it. This made the entire thing escape its hiding place even faster. With every inch that came out, Katsuki’s eyes grew wider.
Just how big was this thing?!
At last, Izuku’s dick stood proud against his stomach and the dragon was panting softly. His erection was about ten inches in total, fat at the base and slowly tapering off into a rather small head. It was lumpy, covered in tiny bumps and ridges and even a few fleshy barbs that thankfully didn’t hurt when Katsuki’s hand skimmed over them. Izuku mewled up at him. Katsuki swallowed thickly.
Yep. It was a dragon’s dick alright.
“Kacchan… Kacchan!” Izuku repeated, almost pleading.
Okay, welp. Katsuki had just made a horny dragon fully erect. Now what? That sick part of himself was trying to convince him that continuing to stroke Izuku’s dick and watching him cum was a good idea. But an even sicker, more depraved part of himself had reared its ugly head in the form of Katsuki’s own hard-on and instead screamed at him to get the balm he used for treating injuries. The human scrambled to do just that.
Izuku watched him with a heady listlessness as Katsuki fumbled around with his belongings until he found what he was after. An herbal balm he had concocted himself and perfected over years of trail and error. It was slick and didn’t dry fast, and most of all it was safe to use on even very sensitive parts of the body. Katsuki got back into the bed with Izuku before shedding himself of his pants and underwear. Izuku perked up at that wriggled closer to him again.
The dragon’s tongue slipped out of his mouth and licked up Katsuki’s neck again. Clumsy hands pawed at the human’s shirt until a claw caught on one of the strings holding it tightly shut over his pecs. Katsuki chided him for nearly ripping through and instead undid them himself. Izuku wasted no time in digging his hands beneath and gently kneaded his chest. Tips of claws scraped across skin and rough scaly palms rubbed on sensitive nipples. Katsuki groaned and unconsciously opened himself up to any and all of Izuku’s curious little touches.
The dragon practically climbed on top of him, their dicks rubbing together and making them both hiss. Izuku’s tongue slowly left his neck and began to work down between Katsuki’s pecs and towards his abdomen. He squirmed and shuddered at the feeling of that tongue along his belly button. Dragons weren’t known to do things like foreplay, and yet this one’s innate curiosity and fascination with him was making for a fine substitute. The tongue crept all the way down through the rough curly hairs around Katsuki’s dick before snaking up the length of him. He groaned and felt a bead of precum escape him. Izuku made a curious little trill and lapped at it. This caused Katsuki to gasp sharply and he nearly let off an explosion into the dragon’s face on pure reflex.
“Deku, stop!” he instead called out.
The dragon looked like he didn’t want to, but Izuku knew that command well. He backed off and instead looked down at Katsuki with sad and hungry eyes. Katsuki opened up the jar he had fetched and slathered his fingers with the balm.
“Watch me, Deku.” He breathed.
He didn’t have to tell Izuku; he would have no matter what. He always watched Katsuki. The human brought his fingers down low, passed his dick and below his balls. Izuku’s eyes laser focused in on Katsuki’s ass as the human began to work his fingers inside of himself. Having spent all of his post-puberty years alone in the dragon’s territory, Katsuki had felt no shame in exploring his own body to figure out what brought him the most pleasure. A few fingers up his ass wasn’t new to him. What was new was preparing himself before a pair of bright green curious eyes and for a large throbbing inhuman cock that was still standing at attention only a few inches away between his knees.
“Kacchan. Kacchan~” Izuku breathed, shifting a little in his seat. It was obvious that the dragon knew what was coming even if was what happening was foreign to him.
Four fingers in and Katsuki still wasn’t sure if he was ready for what was hanging between Izuku’s legs. He had been hitting his prostate with every thrust of his fingers for a while now and precum was dripping out of his cock profusely. He had had to use his free hand to threaten Izuku away from licking it up with tiny little popping explosions. But at long last he decided he was as ready as he was ever going to be. He removed his hand from his backside and got a little more of the balm onto it before sitting up.
He took Izuku’s shaft back in his hand, giving it a few strokes to lube it up. Izuku gasped and Katsuki pressed his mouth to the dragon’s in a kiss. Izuku didn’t have soft, plush lips like a human. In fact, Izuku probably didn’t get much out of kissing at all. But it was something Katsuki wanted to do and he went along with it without complaint. After that Katsuki turned over onto his hands and knees and raised his ass in the air, presenting himself to the dragon.
“Kacchaaaaaan…!” Izuku said in warbley moan before mounting him.
Izuku thrust himself inside surprisingly gently. Despite going slowly and being aided by the balm and Katsuki’s prep work, the human found himself hissing and forcing himself to relax as inch after inch of increasing girth threatened to split him open.
“Shit! Fuck, Deku!” Katsuki gasped. He felt a tear fall from the corner of his eye and he grasped the furs beneath him tightly. “Feels so damn good! Fuck. Fuck!”
Izuku bottomed out in no time at all and a few more tears fell from the human’s eyes. The stretch was a lot compared to anything else he had ever experienced, it almost hurt! But the feeling of fullness and the dragon’s warmth inside of him made it all worth it. He didn’t get long to savor the feeling before Izuku was snapping his hips and fucking into him roughly.
“Oh fuck!” Katsuki shrieked. Despite his outburst Izuku didn’t slow down at all. It was all Katsuki could do to just hang on for the ride, expletives and cries of “Deku!” and “Don’t stop!” and “So good!” kept pouring from his mouth. Every little bump, ridge, and barb of Izuku’s dick caught on his rim and rubbed against his prostate in ways he couldn’t have imagined they would. Or he might have been able to given enough time. He didn’t know. Didn’t really care either. His mind was getting far too hazy for proper coherent thought far too quickly and all he could focus on was Izuku inside of him and his rapidly approaching climax.
It was all too much. Katsuki brought a hand down to himself and began to pump his cock in time with Izuku’s frantic thrusts. It took mere seconds of that for him to spill himself onto the pants he had been wearing that he had strategically put beneath him. Izuku clearly felt the human’s orgasm ripple through him, as he gave a little snarl and thrust even harder. The stimulation was too much on Katsuki’s poor body as it tried to come down and he ended up whimpering, sobbing quietly at the overstimulation into the furs of his bed. Thankfully, it only took Izuku maybe a dozen more thrusts before the dragon emptied himself deep inside of Katsuki.
The sensation was warm and weird. Katsuki shuddered. Izuku remained still for nearly a minute, his cock twitching inside of Katsuki with the last dredges of his orgasm. Then slowly, with a lot more care than Katsuki would have expected, Izuku pulled out of him.
The two of them collapsed onto the bed beside each other. Izuku stared at him with those same big green eyes that seemed to find Katsuki to be the most amazing thing in the world. Katsuki couldn’t help the little smile that played at his lips and he stared back. Never in a million years would Katsuki have ever thought he would fuck a dragon, and yet here he was, having done just that. At least, by some people’s definition. It sure fit his.
Izuku wriggled an inch closer and pressed their lips together like Katsuki had done.
“Kacchan. Love…Kacchan…” the dragon murmured. A little rumbling started in his throat, as if he were purring.
Katsuki’s eyes widened. “Did you just…?”
“Kacchan~” Izuku sleepily wrapped himself around the human’s body, snuggling in close and continuing to purr.
Katsuki laid stock still, dazed. He wanted to pass it off has him having heard things, but he knew better than to do that. He had definitely heard Izuku utter a new word just now.
He slowly wrapped his arms around Izuku and gently stroked the soft, strangely human curls atop his head.
“Good night, Deku.”