Work Text:
"Come."
Katsuki turned to him swiftly.
His handsome face was bloody; streaks of crimson painted his pale cheeks and his mouth as he panted heavily. His pointy ears flicked up in attention, and he let go of the screaming man whose arm he just mangled. Sharp features contorted with a frightening sneer in resistance, all bloodied teeth and large canines, but Eijirou didn't break eye contact.
"Get hi-him off me! Kirishima—"
The panicked voice of the man made the hybrid turn back to him with a low snarl and an intention to rip his throat out, but his owner clicked his tongue.
"Come, Katsuki."
Katsuki grunted in displeasure and spat at his feet. The man scrambled to shuffle back as much as his injured body allowed him. Blood was pooling around him, adding to the scent of metal in the air. The hybrid wiped his face with his arm and approached Kirishima with a scowl on his face. The big metal thorns of his collar were dripping blood as his victims tried to push him away and grab his neck in an attempt to survive the violent attacks.
He was unstoppable when he was aggressive.
Eijirou smiled at the furrowed brows and reached out to ruffle his blond hair.
"Good job."
A blush bloomed on Katsuki’s pale face, and he lowered his head, though his ears flicked back just for a split second, betraying his emotions. Chuckling at his partner, Kirishima came closer to the injured man and crouched near him. Eyes full of fear met his red ones, and Eijirou smiled.
"Don't ever try this shit again," he drawled. "You don't want me as your enemy."
The man pressed his maimed arm to his chest and nodded hurriedly, sweating bullets and unable to speak. Kirishima patted him on the other shoulder, making him shudder.
"Glad we understood each other."
He stood up, and his eyes swept behind him. A dozen men were lying on the floors of a spacious room, torn apart. Blood was sprayed on thin shoji and tatami, even on the low ceiling.
The gory scene—Katsuki's work—was straight out of a horror movie, but Kirishima always found beauty in red.
"Heel."
He walked out of the room with Katsuki by his side, leaving the sole survivor of the meeting to take care of the mess they made himself. Though it was more of a planned ambush in an attempt to threaten him than a meeting.
Fools.
They wandered inside a big house with Katsuki grumbling at the blood drying on his hands and face and scratching it off.
"..Fucking piece of shit," he snarled, ripping off what was left of his tank top and baring his torso. "Stupid clothes."
Eijirou chuckled. "Are you mad at clothes, or are you mad I didn't let you kill him?"
"Should've finished him off," Katsuki snarled immediately, still walking closely to his owner. "What if he stabs you in the back later? Huh? What then?"
Kirishima hummed, pushing open the heavy wooden gates of the estate they just wreaked havoc in.
"In that case," he said as he held the door for Katsuki. "You'll have my back. Like always."
The hybrid flushed pink once again and walked past his owner to the car, cursing under his breath. But Eijirou was sure that if his tail wasn't docked, it'd be wagging.
For someone so bloodthirsty and vicious, Katsuki was cute in his own way. Though Kirishima understood that his demeanor mostly came from his brutal past as dog hybrid in the underground fighting ring.
He remembered the day he first saw him in the cage ripping into another hybrid ruthlessly like it was yesterday. Obsessed, mesmerized, infatuated—those words were too small to describe what he felt back then and now.
Katsuki captivated him and for the lack of better word, Eijirou would say he fell in love. How could he not?
The hybrid was a killing machine. So savage that the organizers of the pit fights had to put a metal cage around the ring for him not to jump out and attack spectators in his wild frenzy. Kirishima was invited by a business partner to witness something "spectacular," and indeed, he saw something extraordinary.
A diamond in the rough.
The blond Doberman, a rare species among other dog hybrids, never lost to anyone.
When Kirishima found him on the benches after his fight, bruised but clearly satisfied, he snarled but let him sit closer after giving him a nasty glare.
That's how their post-fight talks started.
Mostly it was Eijirou, of course. The blond never spoke first, but talking the hybrid's ear off was easy, as Kirishima expressed his fascination with Katsuki's power, which seemed to appease the grumpy fighter. Katsuki let him sit by his side as he scarfed down his post fight meal and counted the money he earned from bets. Early on, Kirishima realized that the hybrid was homeless, sleeping on the benches with his bag under his head. He had nowhere to go, barely making ends meet to buy food and not fight on an empty stomach. His explosive character didn't let him work a regular job, and a fighting pit was the only place where he wasn't suffocating from the boredom of mundane life.
Eijirou also learned that Katsuki loved winning more than anything. He lived to fight and come out on top. Releasing his energy in life or death fights, the Doberman had an adrenaline rush like no other.
He even joked that it felt better than sex. To feel how his fangs tore into flesh, that is.
Kirishima listened to his rare gruff comments, fascinated. Katsuki was fierce, smart, and incredibly honest. And with the way Eijirou had a violent streak in him and an obsession with power, his attraction to the enigmatic hybrid made sense.
He even started to bet on him as time went on, which made Katsuki grin and show off in the ring just for him.
After months of post-fight conversations and Katsuki's affirmative grunts, Eijirou promised him a home and the rush of the fight he was seeking so much in exchange for his loyalty and partnership. He had something else in mind instead of partnership but he understood that he needed to move slowly.
Katsuki moved in with only a backpack full of his clothes and essentials. It was interesting how he only needed a couple things in life, indifferent to luxuries and pleasantries. At first he was wary of everyone in the house, snarling at Eijirou's men if they moved too quickly in his presence. He only was somewhat patient to the maids in the house when he learned that they were the source of food.
Around Kirishima though, he was nonchalant, but the man wasn't stupid. He felt how the hybrid tensed whenever he joined him for meals or asked if they could work out together in the basement gym. That was one thing that Katsuki seemed to enjoy a lot. The treadmill was his favorite as he ran and ran with a grin on his face. Sometimes he even let Kirishima spot him and the man was offered the exquisite sight of a sweating and panting hybrid who refused to lower the weights, pushing himself to the limit.
After some time, he stopped being so tense around Eijirou, and the man started to bring him around more. It raiseda lot of questions from the circles he ran in, as everyone was a bit appalled that the usually lonely Kirishima had company for once.
Bringing the hybrid to meetings and business functions was a risk, but Kirishima took it nonetheless. He was willing to bet everything on the blond Doberman, and soon enough, Katsuki proved his loyalty.
When he attacked an assassin who was about to stab Kirishima at the noisy clan gathering, Eijirou fell head over heels once again. Katsuki, bloodied and growling, was maiming the poor man like he was a rag doll, leaving pools of blood all over the place as he dragged him back and forth, prolonging his death. The representatives of the clans were shocked and terrified, yet Kirishima was hot with want.
That night, Katsuki was howling under him for the first time. And ever since, they were inseparable.
Aggressive and violent, the hybrid fit just right into Kirishima's life.
His keen instincts, sharpened by thousands of fights, made him hyper aware of miniscule changes in anyone's behavior or voice, let alone smell. Having him at tense negotiations meant having a ticking bomb by his side, but Eijirou liked how the blond hybrid seemed to take on his role of protector and stood guard in every situation with nothing ever said between them.
It was fascinating to watch him take down thugs that allowed themselves too much in Kirishima's presence or, god forbid, steal some goods from his warehouses.
There was no hesitation in Katsuki. There was no warning or wasted movement either. He didn't posture or threaten, ending any altercation he found himself in immediately. The way he pounced—it was fast, brutal, and efficient.
And Eijirou had seen violence before. He had been in the military, now retired with honor, then went into the black market business and now was tied to criminal syndicates around the country.
He knew violence. Lived in it. Breathed it.
But Katsuki—
Katsuki was violence.
Sometimes, he would get into a certain headspace where he didn't stop. It was like a flow state, in a sense, though Eijirou felt like it was a vulnerability from the hybrid. Katsuki would continue to fight and kill like he was cornered too many times to ever allow it again.
With that came a realization that he needed control. Something to anchor his explosive behavior.
Thankfully, Kirishima's military background came in clutch when he started to train the hybrid to break that flow state when it became too much. As prideful as he was, Katsuki was resisting a lot in the beginning. They even got into fights a couple times, and Eijirou had several deep scars from the enraged hybrid's teeth. He didn't take it too seriously, knowing that it would take time for Katsuki to even consider listening to orders.
Things started to change when Katsuki came to his study after their big fight that left Kirishima with bleeding bites on his arms. The hybrid scowled and sat in one of the chairs in silence while Kirishima worked.
At first, Eijirou didn't acknowledge him.
That, in itself, was deliberate.
He kept his eyes on the paperwork spread across the desk, pen scratching steadily as if there weren’t a volatile, bloodstained hybrid sitting just a few feet away, radiating irritation like heat off the asphalt in scorching July.
Katsuki shifted. A low, impatient huff left him as his feet tapped against the wooden floor.
"…Oi."
There was no response, and the tapping grew faster.
"I know you hear me."
Eijirou hummed absently, flipping a page.
"Sit properly." He said it casually, but it was a command and of course, Katsuki's hackles rose instantly.
"The fuck did you just say?"
Eijirou finally looked up. Their eyes met—auburn against crimson—and he could hear a growl bubbling in Katsuki's throat.
"I said," he repeated, calm as ever, "Sit properly."
The Doberman was sprawled in the chair like he owned the place—legs wide, posture loose, defiant. Blood still stained the lines of his jaw, drying in thin, dark streaks.
For a moment, it looked like he might lunge. His lip curled, revealing a sharp canine.
"Don't order me around like some pet."
Eijirou leaned back slightly in his chair, unbothered.
"Do you have to be so stubborn? You are my pet." He watched Katsuki sneer and shift forward, ready to pounce him once again, and he stopped him with a soft smile. "And my partner."
Katsuki's ears twitched and he sat back, glaring at him. He didn't move and Eijirou watched him for a second longer before trying again with more authority.
"Sit."
The hybrid's fingers curled against his thighs. "…You're so fucking annoying."
"Sit."
A tense silence fell but then, with an irritated grunt, Katsuki straightened in the chair.
It wasn't a perfect posture but it was good enough for a start.
"Good boy."
Katsuki’s face immediately flushed and he looked away sharply, though his ears flicked back in embarrassment.
Kirishima drove the last nail in on that day by fucking the lights out of the hybrid and whispering praises and sweet nothings into his pale skin.
It became a pattern after that. Resistance was melting away with every small step that Eijirou took to train him. Katsuki would have been brilliant as a K9 dog, even though sometimes it took a bit of pressure to get him to behave.
And yet.
And yet—
He listened. Begrudgingly, but he did.
With time, the Doberman softened towards Kirishima even more. It was exhilarating, the way Katsuki showed small signs of trust and even rough fondness while being so brutal to everyone else. He liked to sit in Eijirou's study whenever he was busy until they both could go to the gym and on the long walks that hybrid seemed to enjoy a lot. He followed him around, always close by his side and whenever Eijirou pointed that out jokingly, he would blush and hide his eyes but never leave. It was cute and sweet that he curled up next to him on the couches and in bed, if it was raining outside and they couldn’t go out. His smug grins and cocky remarks were often making Kirishima laugh his heart out, and he noticed how sharp smiles would turn a bit softer.
Their bond was growing day by day, strengthening from the way Katsuki let him take control more and more. Even in the bedroom, the hybrid started to trust him.
Katsuki liked how Eijirou was pushing him into obedience in bed. His facade would fall, leaving him blabbering sweaty mess.
Just like tonight.
The thorny collar was left somewhere on the floor among ripped clothes. The room was dark, but Eijirou didn't need to see.
The sounds were enough.
Katsuki growled, pushing back onto his cock. The once tight hole was gaping and sloppy with cum from earlier, squelching with every deep thrust. His arms flexed as he tore into the blanket and pillows under him, panting and taking Kirishima’s dick like the good little slut he was.
For someone so aggressive and dominant, he was squirming from a good fucking like a bitch in heat.
Eijirou gripped his nape, squeezing, and felt Katsuki shudder with his whole body.
"Shh... I know what you need, pup," he groaned, thrusting deeper. His hand snaked to his waist, gripping and pulling him up to stick his ass out more.
Katsuki groaned, wiggling in his grip and canting his hips for more. "Eijir-rrou! F-fuck, give it to me—" he snarled when the man fucked into him in a couple of rough thrusts, jamming into his prostate. "Yes, fuck! Yes!"
"Little whore," Kirishima moaned, leaning in and increasing the pace. Pleasure was thrumming under his skin as he plowed into him with long, deep thrusts.
Sweat slickened them both, and he knew Katsuki's sensitive nose made sex even better for him. He once told him that he could smell whenever someone was aroused and the rush after letting out steam turned him into an insatiable ball of horniness. So after every bloody scene, like today, when the hybrid was still high on adrenaline, he demanded Eijirou to fuck him till he was a sloppy mess.
For all his poise and surly attitude, the hybrid genuinely enjoyed fucking.
Loud plaps of Eijirou's ballsack against Katsuki's taint filled the room along with lewd moans and snarls, and the man chuckled when the hybrid tightened up, hiding his face in the pillow. "Don't be shy now, pup... Mm, still tight like a virgin... Bet you're already knotting, mm?"
Reaching between his shaking legs, he found a hard, leaking cock. Slick instantly covered his palm as he stroked the throbbing shaft. His fingers curled around his dick, making Katsuki let out whorish moans. The wet tapered tip was oozing so much precum his hand was slipping up and down like Katsuki already came. When his fist bumped into pulsing glands at the root of the hybrid's cock, he smiled triumphantly and started to pound Katsuki into the bed. His fingers curled around throbbing flesh and his lover shivered, grunting and thrusting his hips into his palm needily.
"Come for me, Kats," he whispered into his neck, licking salt off his skin. "Be a good boy."
Immediately, Katsuki froze. The tight squeeze of his hole made the man shudder with pleasure and hot cum started to overflow in his fist. A raw growl shook the walls as the strong body twitched and trembled against Eijirou. He felt how the heavy glands of Katsuki's knot expanded in his palm, releasing thick ropes of cum. Stars danced behind his closed eyes as the hybrid's hole pulsed like a vice around his cock.
Heat unfurled in Eijirou's guts as an orgasm hit him, almost blinding him. With numb legs, he flopped onto his side, taking Katsuki with him and squeezing his knot. It was thick and warm in his grasp and he ground deeper, pressing on an overstimulated prostate and driving the hybrid up the wall. He shivered in his hold, panting and still coming. His poor cock was shooting cum again and again, soiling the sheets and the fair skin of his hard stomach.
It was incredibly erotic how much Katsuki could come.
Kirishima pressed soft kisses onto the slope of his shoulder, still massaging the pulsing knot. His palm was a mess of cum and slick and he let his other hand wander and pull on pebbled nipples, knowing how it made Katsuki's orgasm brighter. The hybrid let out a throaty moan, and another flow of cum erupted into Eijirou's hand. He smeared it on Katsuki's coarse pubes and lower stomach, bringing his fingers back to wrap around the thick knot and massage it, milking it for more as his own cum was slowly leaking out of the wrecked hole when he started to soften.
"...S-stop," Katsuki huffed, grabbing his arm, at which Kirishima chuckled, kissing under his ear.
"Don’t lie to me. I know you want more."
He stroked the still hard cock, flicking his wrist. It made Katsuki tighten around him again with a strangled moan, losing his mind to the numbing micro orgasms that he experienced when he was fucked deep and rough like tonight. Eijirou's fingers reached lower to feel his balls and play with them. The hybrid's protesting grunts were turning into breathy pants as he tried to deny his desires again but ultimately failed once his owner's hand went back on his knot.
"Nghh... No... F-fuck! Fuck, yes—Eijirou, nghhh..." he slurred and Kirishima felt how he nuzzled back in rare affection. He must have been drunk on his pleasure to show this much fondness. "...Feels so good."
Eijirou cooed, smearing hot cum on the hybrid's stomach and giving him a slow belly rub. Katsuki sighed in delight, melting at his side and letting him play with his hard cock, still coming.
"I know, pup."
"Don't call me that—Mmm, fuck..." Low grunt that was followed up by a moan made the man chuckle. Another load of cum spilled over his soiled fingers when he pulled out completely, making the hybrid hiss. Eijirou let go of Katsuki's stiff dick, getting more comfortable on the bed, and the Doberman huffed, turning on his stomach to glare at him.
"What's so funny?" he grumbled, but even in the darkness of the room Kirishima could see how he humped the bed.
"You're cute," he chuckled, pulling Katsuki closer by his waist. "Come here."
His hand snaked to squeeze tight asscheeks and made the hybrid shudder against him. A hot breath hit his chest as a hard pulsing cock pressed against him.
"I am not," Katsuki groaned, now humping him and Eijirou let him.
"Sure," he whispered into a panting mouth, kissing a grumbling hybrid. Heat pooled in the pit of his stomach again when he felt a hard dick thrusting against his navel with Katsuki's needy squirming. He felt the Doberman drooling, groaning and slurring his words while chasing another orgasm.
"C'mon, f-fuck—Can't you get it up again?" he snarled, stuttering as Eijirou gripped his hips and helped him to direct his thrusts more efficiently. Cum smeared between them with a filthy squelch and Katsuki moaned, shuddering on top of him and adding more to the sloppy mess on their bodies.
"I can't do it on command, Kats," Eijirou grinned. "Unless you help me with that mouth of yours, mm?"
Katsuki huffed. "Just say you want a blow job, bastard."
"And you're gonna give it to me," Eijirou ruffled his hair, touching his flicking ears. "Aren't you?"
The hybrid didn't respond. Instead, he bit his chest softly and his body slid down in one smooth motion. Hot breath fanned over the man's half hard cock while a firm hand stroked him roughly. Eijirou grunted, feeling a wet mouth descending on his shaft and making him lose his breath.
"Good boy."
His partner—his pet—listened to orders.