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“Its in the gas!” Deku screams from within his ventilator, hand on his ear to turn on his earpiece. “Don’t breathe it in!”
There’s no answer from Kacchan. A moment of crackling silence, as Izuku flies up and out of the gas cloud. The villain is on the run, out towards the industrial area where half the buildings were empty and abandoned, and the other half were mostly factories. Theoretically, nobody should be around and be affected by the gas.
A snarl in their comm, and then a buzzing crack.
Something blasts to his left, and he’s changing direction immediately with Black Whip.
“Got him.” Katsuki’s heaving satisfied voice comes over comms. It’s strangely distorted. “But we got about three minutes before this gas takes me over. Deku. Get out of here. Send in a quelling team.” Then there’s a crunching noise, and the signal dies.
A quelling--- no!
“Kacchan!” Izuku cries back, panicking. He swings in, glad for his ventilator.
Katsuki’s sat on an overturned piece of concrete, head hanging, the villain wrapped up in capture tape and muffled as well, unconscious.
The gas is slowly dissipating, but not soon enough.
Red eyes meet with green, irritated.
“Don’t argue with me, Deku!” Katsuki barks, but Izuku realizes the other is pretending. His fists are clenched tight, his arms crossed. He’s got the same particularly grit in his jaw that he normally gets, when his alpha is riled up and angry, and he’s trying not to lose his cool. He notices Katsuki’s destroyed earpiece, probably half snapped in the fight and further destroyed when Katsuki had yanked it off.
If there’s something Katsuki hated more than anything, it was being, or feeling out of control. Rut was the pinnacle of such a feeling, and they were too far away from his apartment to lock down and let him take care of it privately like he would on a natural cycle. A quelling team meant Katsuki would be brought down by force, tranquilizers to knock out an elephant. He’d be kept drugged and biddable in a lock-down hospital, the rut leaving him burning and in pain for days, perhaps weeks.
“I’m arguing,” Izuku snaps. “It’s possible the tranqs won’t even work on you!”
“I said what I fucking said, get out of here, Deku.” Katsuki replies, red eyes hot with anger. It verges too close on an alpha command, and no, Izuku won’t accept that, won’t accept it at all! Katsuki had never used his command on him, and he won’t this time. He won’t…he won’t have to!
Clenching his fists, Izuku doesn’t stop to think.
Katsuki’s mouth drops, as Izuku yanks at and then shakes his chin free from his ventilator, taking a good long inhale of quirked gas.
His nose wrinkles since it tastes like sweaty socks. He doesn’t feel the quirk ignite, but as Katsuki said, it would only take a few minutes.
Izuku’s head snaps to the side, cheek blooming in pain, when Katsuki punches him in the face.
“What the fuck are you doing?!” Katsuki’s alpha rears up in his throat, darkening his words and turning his eyes heavy and black. “What the fuck have you done?!”
Rubbing at his face and glaring back, Izuku snarls up at the alpha who’s five inches of extra height had never looked taller.
“I’m not leaving you to deal with this alone!” Izuku shows his teeth, his omega coiling tightly inside. Perhaps the gas was already affecting him, but they were a bare two minutes away from it taking over Katsuki entirely.
“You fucker, a quelling team coulda knocked me out and binned me for a few days, that’s all! Now you’re fucking, you’re gonna get this quirk all up in your head too, don’t you remember what it does?!” Katsuki seethes, stomping closer and dragging Izuku up to meet his glare by his uniform. It’s rough handling, and Izuku’s feet scrape to stay upright.
“I remember.” Izuku hisses back. “I remember the victims suffering, I remember the doctors saying their ruts would have been quicker and safer with a partner.”
“That was for civilians, you motherfucker,” Katsuki grinds his teeth, leaning in. His voice is guttural, bleeding rage. “What do you think it’ll do to an enigma?!”
Kacchan’s an enigma.
Something in Izuku’s stomach genuinely quails. His omega screams at him to roll over, to flee, to do anything but challenge him back, this primal beast of conquering savagery. Kacchan’s an enigma. There hadn’t been an enigma affected by the villain’s gas, just alphas and they had fallen into extreme ruts, desperate for satiation but unable to achieve it. They had no idea how it would impact Katsuki’s specialty class gender.
“I’m not going to let you do this by yourself.” Izuku stands by his decision. Too late, anyway, he’s already breathed it in. The omegas had undergone a faux heat, which would help them both survive Kacchan’s rut and ease the pain of the quirk’s demands.
But Kacchan was an Enigma. An Enigma alpha.
“You piece of fucking shit. Deku.” Katsuki’s brows are furrowed, they tremble with the twisting in his expression. “I’m going to hurt you. This isn’t how I wanted…” It’s almost desperate, almost fearful. The hold on Izuku’s uniform becomes a grip along his shoulder and neck, the other hand latching onto his hip and pulling him in, and in, under the shadow of Katsuki’s body. The energy between them has changed. Izuku’s omega is picking up something different, some new kind of scent. Or, the gas was starting to affect him.
From so close, Izuku gets to watch as Katsuki’s pupil expands until he nearly looks alien. Katsuki’s red irises are disappearing under pupil, turning black, turning him into someone, something that looked like Kacchan, but had no Kacchan looking back.
“It’ll be okay,” Izuku says, breathing it, head swimming suddenly from the scent of Katsuki. It’s stronger, so strong, so thick. The quirk is taking effect. “I want this.”
“You stupid, whorish omega fuck—” Katsuki growls the words, deep, dark, and rumbling. The presence of him, of the frightening power of the engima grows to be a near physical sensation and Izuku surrenders to instinct.
He flees.
With a flick of his quirk and quick feet, he’s out of Katsuki’s grip, using his Black Whip, scaling the building and running. Bzzt, bzzt.
“Come in!” Izuku snaps into the comms piece, as Katsuki roars out behind him and blasts off with concussive force. “The villain is apprehended, intersection of Xx and Yy, he’s wrapped up in tape and waiting for you. Suit up, his quirk may still be in effect.”
“Copy. Hero Deku, where are you?”
Izuku pants, leaping upwards to the nearest roof and running. Katsuki’s blasts end abruptly, and a quick glance behind finds the man charging after him. Hunting him. Izuku uses One for All and green lightning’s his way sideways, taking a sudden evasive turn and leaping for a broken in window in the parallel factory. Abandoned.
Dusty.
He tamps down his quirk and darts further into the dark building.
“Hero Deku!”
“Hold.” He whispers. “Leading Hero Dynamight away, he was affected by the villain’s quirk. Too late for a quelling team. I’m taking care of it. Going dark.” And he rips the earpiece out, dropping it in the dust to smash it under his heel, to destroy the tracker.
Oh, that’s a problem for future him.
He finds a stairwell which seems half held up by graffiti and uses his every sense to try and figure out if Katsuki had followed him inside. He judges they were at least half the district away from the quirk site, from where emergency would be picking up the villain.
He tamps down his quirk and ducks his way around a pillar, eyes peeled.
Izuku’s breathing is labored, as he huffs his way to another floor. It’s an abandoned building, probably never finished in the first place. Bankruptcy and recessions leave these things half-built all the time, and it’s evident with the piles of rotten wood, the rebar, the unfinished concrete floors that nobody’s been around to disturb in a long, long time.
Izuku realizes he’s leaving behind footprints and only has the time to worry for an instant. Sweet, cloying, heavy, sour like it's been burnt. It's a scent he's known all his life, but he's never been so drowned in it. Izuku stumbles as Katsuki's alpha scent fills his nose and strikes him directly in the stomach, insides clenching.
Walking silently in his big combat boots, Katsuki had headed around to cut him off. Followed him, anticipated his movements. Hunted him down like some stalking predator.
The heat in his guts increases.
“Izuku.” Katsuki’s voice growls from the shadows like some beast of darkness. Izuku turns to face him, heart pounding, omega squealing inside. The other alphas hadn’t been able to speak. “I’m still…mentally here. I know what I’m doing.” His words are half strangled, his breath panting. “But I want to fuck you. Going to fuck you—”
Izuku realizes his thighs are wet. He realizes this, because he’s squeezing them together, rubbing them together, his cunt aching hot, his core flexing with a sudden flare of arousal that feels like a goddamn punch.
“Kacchan—” He starts, whining it, shocked at himself.
Heavy boots scrap over the concrete floor. One knocks aside abandoned rebar as Katsuki slowly steps closer. The light from the window (a pale cast turning Katsuki’s blonde hair white, his eyes into deep, dark foreboding pits) sends both their shadows sideways, taller and taller than ever. Kacchan's always been bigger than him. Not just taller, but wider in the shoulders, thicker in the arms. At the moment, Izuku has no thoughts of fighting back, some creature of instinct inside him saying he would lose, it would end the way all of Kacchan's fights end.
With his victory.
It's tantalizing. The thought, of losing such a battle, being forced to the ground, taken. It makes Izuku's omega scent bloom just a bit more. Trying to compete with the enigma, trying to entice him.
“You have to promise me,” Katsuki gasps out, ripping at his gauntlets, then his gloves, then the bandolier around his shoulders. All of it drops to the floor, and Izuku is mimicking him without realizing it, gently puling at his gloves, then his ventilator.
The touch of his bare fingers to his face is a shock, electrifying, making him gasp, mouth dropping open to moan. Katsuki snarls, punching the pillar nearest him, eyes not leaving his captured omega.
Heat in Izuku’s head, his chest, his gut. His cunt.
“Promise, I promise--”
“No!” Katsuki snarls, lunging halfway forward. His pants are opened, the bulge in his briefs apparent and heavy and stinking so much of enigma, of alpha, Izuku can’t stay on his feet.
His knees ache within their pads when he hits the concrete, but he obeys and looks Katsuki in the eye, trying to pay attention.
“Promise me that you want this?” Katsuki asks, one final breath of the man instead of the animal.
“I do, I’ve always wanted this, I never thought this would be how we—” Izuku starts babbling it, crying because his insides hurt and so does his heart, “—I’m sorry, I’m sorry Kacchan, I’m sorry I forced it like th-this but I want you so bad—”
He's soothed. Palms cup his cheeks, and Katsuki is shushing him, drawing thumbs over his freckles and pulling him into his shadow. Izuku’s chin finds Katsuki’s pant’s zipper, and he moans, muffled by the clothed cock pressed tight to his mouth.
“Good, I want you, always I wanted you, omega, my omega. Hunted you down. So fucking good. On your knees for me, so good, omega.” Katsuki starts a slow drone of praise, and Izuku is spellbound, lost in the haze of the quirk and the smell of Katsuki’s lust so apparent.
The cock flexes against his lips, and Izuku pets at Katsuki’s thighs, reaching to yank on the pants, the briefs. He wants to taste.
Enigma, Kacchan’s an Enigma, the best, the strongest, the one who can pup, oh imagine, imagine strong, red-eyed alpha pups.
Izuku’s underwear floods, and he shifts on his knees, finding blonde pubic hair with his nose and rubbing his face there, right there at Katsuki’s groin like a cat, marking it with his scent. Marking himself with Katsuki’s strongest, thickest scent.
“My good fucking omega, gonna fuck your mouth. Gonna fuck your cunt. Gonna knot you and fill all your goddamn holes with my come.” Katsuki growls down at him, and Izuku can’t quite focus, swimming in lust and now that cock was pulled out of briefs, shoved down thighs, and it lays heavy over his whole face. With one hand in green hair, Katsuki uses the other at his base to slap it, hard, over Izuku’s cheek. Again, another hit hard and heavy, it makes him turn his head. He gasps, mouth open and wanting.
Katsuki laughs.
Kacchan's cock is so big, he's always been big here too. And yet it's never seemed so monstrous, so incredible.
Licking at the heavy scrotum, with Katsuki’s large dick painting his hairline with pre come, Izuku moans around the sensitive skin and yanks hard at Katsuki’s pants, bunched at his thighs. He wants it, oh fuck, he wants it. An emptiness pangs in his pussy, up in his insides like he's feeling the phantom hurt of Kacchan's cock all the way in. It hurts with pleasure, so even though his eyes spark with tears, Izuku still wants it more and more.
The alpha stumbles, swears, and fucks forward with his hips. The grip on his hair turns punishing.
“Omega--” Katsuki warns.
“Alpha, mouth, you wanted—my mouth,” Izuku pants, amazed he can find and use words at all and moaning in delight when that heavy, fragrant cockhead draws a line down his eyebrow and lid and cheek to his lips, slapping there against his mouth until Izuku obliges and sticks out his tongue.
“God that looks good,” Katsuki groans, eyes entirely black. He pumps forward just a bit but uses his grip on Izuku’s head to keep pushing him back, fighting against the omega straining to get his mouth down that cock, to suck him into his throat. “I’ve thought of this. It’s more beautiful than I ever thought.”
“Ahhh—nn,” Izuku tries to respond, but with his mouth open dumbly and tongue stuck out, all he can do is moan, eyes rolling when Katsuki finally allows him to sink down.
The cock is big. It’s thick, and heavy, and fills his mouth easily. He gags when it prods deep in his throat. Not that such a thing stops Izuku, wouldn’t stop him, with the rising heat in his stomach urging him on. He swallows.
Katsuki’s head falls back, then rolls. It’s like something had come to life within him, something made of darkness and desire and the urge to fuck. To take.
The cock moves in his mouth, twitches, grows bigger.
Izuku’s swallowing the excess saliva, but also moving, trying to pump on that cock and swallow it, trying to give his alpha pleasure.
“Mnn,” He groans around the head, finding the slit and licking away the swelling pre come that tastes so strong.
With his head fallen back, Katsuki pumps his hips to match Izuku’s messy devouring. Izuku blinks his eyes and tries to squint upwards, wanting to see his alpha, wanting to lock eyes and show him how good he can be.
Then Katsuki slaps his cheek, lightly, even while his mouth and throat were full of cock.
Flushing hotly, Izuku’s cunt flexes and he stuffs his fingers between his thighs to rub at it, to try and touch himself even through his uniform.
Katsuki slaps him again, a bright, clean smack that makes him moan around alpha’s cock and gargle, gagging, wanting everything, all of it, wanting to choke even.
His eyes roll.
When he focuses again, panting, tongue out of his mouth and no cock in his throat, he finds Katsuki staring down at him with an odd grin. His teeth look bigger than usual, sharper. One of his hands cups Izuku’s chin, the fingers pressing in tight to force his jaw open. A thumb crawls to the corner of his mouth, pulling the cheek aside.
“My omega.” Katsuki whispers, enigma in his voice and taken over his eyes. The smile turns downward into a snarl, and Izuku whimpers, letting the fingers holding his chin enter his mouth, sucking them just as he did the cock. “Mine, now.”
With his thumb, Katsuki keeps Izuku’s mouth open, and spits. He half misses, and his spit collects with Izuku’s on his pressure swollen lips and pink, flushed cheek.
Katsuki steps back and away, leaning down to clasp Izuku’s upper arms and lifting. For some reason, Izuku’s legs weren’t working, he couldn’t find his feet and simply clutched back at Katsuki, fingers weakly gripping at his uniform top. His own mouth is drooling, Izuku realizes, spit smeared down over his chin and staining his neck.
“--Acch—n.” Izuku tries to say, but his throat was abused beyond use. His tongue thick, he couldn’t form it around words.
Taking him in, Katsuki’s feral expression spasms, his teeth seem to grow in his mouth, and he sways closer, head lolling to the side just enough that their lips brush. Then Katsuki snarls right here in his face and Izuku’s eyes roll back in surrender, his cunt blurts out a desperate surge of slick, and he shivers in heightened arousal, weak against the enigma’s mere presence, his grip.
“Izuku—” Katsuki groans out, ripping his head away and glaring.
He physically throws Izuku to the ground. Whimpering with the sudden hit of concrete, Izuku’s head swivels, seeking his alpha out, wondering what he did wrong. Fighting to get to his hands and knees, Izuku realizes Katsuki’s stripping himself behind him, and weakly, he tries to crawl away.
If he doesn’t, he’ll get fucked right here in the dirt. Didn’t he have a nest somewhere? Didn’t he have a safe, secure, warm, comfortable nest? Why hadn’t alpha taken him there? Why would he fuck him, here, where they were vulnerable.
A presence, behind him. Kneeling there so Izuku's captured, the alpha rearing up behind him. Fuck him, oh, fuck him please-- but wait, unsafe, unsafe, he needs--
“Shh, shh,” Katsuki puts a palm to his nape and pushes, forcing Izuku down to the floor. He expects concrete dust and dirt and rocks but instead meets with the thin layer of Katsuki’s uniform. Nuzzling his nose into the fabric, Izuku croons. Better than nothing, and it smelled just perfect, just like his alpha.
Katsuki fights with Izuku’s uniform zipper, accidentally yanking it the wrong way and breaking the metal. Gurgling, because the yank pulled at his collar, Izuku whimpers loudly and is rewarded with a deep warning snarl and his uniform being ripped to shreds, smoke trailing up out from the remains.
Katsuki blasts didn’t hurt, just enough to burn fabric, but Izuku cries out anyway, ecstatic to feel air over his drowning cunt.
“Kacch—” He tries to whine, burying his face in the black fabric in his arms and raising his hips as high as he can, on his knees, then wobbling weakly onto his tip toes, trying to give Katsuki the best view, the best angle.
“Fuuuck—” the word is drooled into his pussy lips, then licked up by a firm stroke of tongue. The tip catches over Izuku’s insanely sensitive clit, and he squeals, shivering on his balanced position and trying to regain balance on his toes. Arms wrap around his thighs and hoist him up, leaving him to hang in Katsuki’s grip and quiver as he eats him out.
All sense of coherence and consciousness abandons Izuku in favor of drowning omega lust and need and the desire for breeding.
Katsuki has the wherewithal to take care of his omega. He did. Does?
Unfortunately, his brain was also overrun with a blanket of quirk-induced rut desire, the enigma controlled his alpha as best he can but found he was failing the more Izuku became bare before him. He wishes for a nest but knows there’s no other choice. He’s claiming this bitch for himself, now, today.
And then, beneath freckled ass cheeks and a furled pink asshole those swollen pussy lips are exposed, the green hair smeared around in a mess from the overabundance of slick, the clit engorged nearly the size of Katsuki’s fucking pinky, so fucking beautiful and tasted---
With the flat of his tongue, Katsuki catches as much slick as he can, and the licks and licks, and licks. With his lips he kisses at Izuku’s cunt and with his tongue he fills him, finding a hot, gaping hole ready for him, for his knot.
If the quirk gas hadn’t already ensure it, the taste of Izuku would have sent him into rut.
He doesn’t eat Izuku out until orgasm. Can’t even really think about it. Instead, he licks and licks because he wants the taste, until he realizes he can fuck him instead, put his cock in him, mate him, breed him with cock and knot and come.
“D’ku—” Katsuki grunts, smearing his mouth down the side of Izuku’s thigh, then up and over his ass, biting his way there. It’s too hard, the marks bloom too fresh and red. But Izuku just whimpers for him, pleading for more, shuffling onto his knees.
Katsuki puts his hand between Izuku’s shoulder blades, and shoves. It flattens Izuku to the floor, but the heat crazed omega just writhes there, trying to circle his hips, an instinctive primal motion. Meant to urge the cock in, meant to flick the hips and capture a knot, clutch it tight and use it to come. A heavy alpha cock bumps a chubby, swollen pink pussy lip.
He humps, helpless with instinct, missing but rubbing his deepest scent all over his bitch all the same. Katsuki’s going to fuck his omega, he’s going to fuck Izuku, his Izuku, Deku, the one who’s been at his side all these years and who he demands stay there for the rest of them.
Alpha roars, and takes over, and Katsuki’s got his cock in cunt, bottomed out in the first thrust.
Beneath his palms, Izuku loses his air, pressed out of him from the sudden filling, and without any room to recover because Katsuki’s already fucking him. Rough, long thrusts that pull out then slap back in, his balls hanging heavy and fuller than they ever had been, ready to fill him up. Izuku is pushed forward with every thrust, then pulled back into it by Katsuki’s harsh grip on his hips.
Everything swims, turning darker.
Katsuki’s hunted his omega down; he’s fucking him in the dirt. Caught him and shoved him to the floor and mounted, put himself inside, taken over that cunt because it’s his now. His. He fucks forward, and Izuku cries out, whimpering with each thrust, hands clutching tight to his gifted shirt (the only way he could simulate a nest, it felt too vulnerable to fuck him here, right here in the empty floor of an abandoned building, in the dirt and the gravel and with the sounds of that wet cunt echoing off bare concrete pillars).
He looks down, watches the ass bounce, looks at that little asshole and gathers up slick with one middle finger, just to press it in and take over more of Izuku’s holes. His finger touches at the delicate skin, feeling the movement of his cock in Izuku’s pussy from the inside, loving the feeling of evidence that he was taking him over, putting his mark on him. He presses in deep, thrusting, curling his hips and Izuku turns his hips, and the omega is crying in pleasure for it, loving it. Katsuki’s cock is strangled each time Izuku tightens up in reaction to his balls smacking against that overly sensitive clit.
His, this is his. All his, only his.
Izuku’s noises get muffled as he hides his face in Katsuki’s black uniform.
Want to see him.
Katsuki reaches forward, and gripping green hair, he yanks Izuku back and exposes him to the air. He’s leaking tears, his mouth is open, his tongue trying and failing to lick his dry lips, eyes rolling back in his head with every world-ending push and pull of cock.
“—‘zuku-“ Katsuki grunts from between sharp, grown teeth. Feels so good.
“Feel perfect, so wet, so fuck’n good you’re taking it—” He doesn’t really have reason to be speaking, has no idea why his voice needed to be heard, but then green eyes roll to him, fix on him, the pupil huge in lust and the pleasure scrawled over Izuku’s face incredible and yes, that, he wants more of that, wants Izuku to look at him, entirely on him, only for him.
He pulls out despite the alpha in him ravaging for more of that pussy. The enigma is in command. Powerful, controlled, top of the hierarchy.
Izuku, lost to his omega, just wails, crying out, literal tears burning in his eyes as he reaches back for his alpha, for Katsuki.
“Whore’s lost without this cock,” Katsuki chuckles, pulling on green hair until Izuku teeters backwards, straining with it, rubbing up against Katsuki’s front like if he whined plaintively enough he would give the cock back.
Katsuki reaches around Izuku’s form and slaps his cunt, harsh and mean. Screaming, Izuku reaches back and scratches against Katsuki’s shoulders, his neck, his face, omega revolting at the treatment, at not getting that cock back in his cunt now. Instead, Katsuki sticks it in the space between Izuku's thighs and uses his wont o force them tightly shut. It makes his cock poke out the front of his little pussy lips, rubbing against the clit and making Izuku shiver there on his knees, forced to take it, wrapped up in stronger alpha arms.
“Slut. Whorish slut, whimpering for it, for my cock. I’d kill anyone who saw you like this. Anyone. Tear out their throats. Blow them into red muddy pieces.” Katsuki hotly whispers into Izuku’s ear, the alpha in him thoughtless with breed-breed-breed, but the enigma, uncaring, tells all his darkest, coldest truths. He humps there, grinding, smearing that mess of omega slick and alpha pre come all around Izuku's holes. "Fucking you, Deku, Kacchan's fucking right here in this empty fucking warehouse. Woulda run you down anywhere, woulda fucked you in the street. Fuck, this cunt. You'd scream for it, hm? Hear that echo? That's you."
Katsuki licks that straining neck, looking down where his fingers were dragging Izuku’s sopping slick from his pussy lips to his abdomen, smearing it there in a messy, disgusting act that he’ll add his come to later, when it’s seeping out of Izuku’s friction worn holes.
He groans around a mouthful of throat, one of his hands holding Izuku’s mouth open, fingers pinching his tongue and making him howl inarticulately at the empty, echoing ceiling. His other hand buries three fingers deep into a wet, open cunt, and his cock throbs against his own knuckles.
Yes.
Yes, his omega. His to touch, to fuck, and fuck, and fuck full of kits and pups and children so Izuku would forever stay swollen and knot-drunk, leaking milk from swollen, hurting tits to feed Katsuki’s goddamn young.
Yes.
Then he yanks and pulls and pushes Izuku until he’s on his back, legs splayed, as centred on the pile of their ripped clothing as he can be, Katsuki stretches out over top and puts his hand flat over Izuku’s chest, shoving the air out of his lungs and pinning him to the floor.
Katsuki pants, grinning with exhilaration. Izuku’s green irises are completely gone under his pupil, the quirk and his faux heat taking over, he gurgles and wheezes and wriggles to urge Katsuki to fuck him again. The knock of his ankles at Katsuki's sides and back are delicious, forceful. Strong omega, he can take it. Can take the fucking Katsuki's about to give him. His knot.
His cock standing proud and wet with his omega’s gushing slick, Katsuki looks him over. His cunt is fucked a hot red, leaking slick down over his ass and puddling under them in long, sticky streams. His belly, smeared with wetness, twists and turns with his efforts to wriggle closer, to open his legs and pull Katsuki in. His face, wanting and desperate and despairing, eyes black with heat, mouth open and panting and groaning.
“—acchan—” Izuku tries, fighting against the arm pinning him down, even when that hand crawls up to clasp his throat, threatening, pinning him like a pup to the dirt floor where he’s been fucked like a whore. “—Kaa—cc’n, plea-lease—”
“Shh, be still.” Katsuki soothes with a single word, enigma sitting behind his teeth, ready to claim. His omega obeys, round eyed and trusting, biting his bottom lip and petting down over his forearm like it wasn’t threatening to grip his throat.
Omega’s so good.
Katsuki agrees with his alpha. Omega is so good.
Idly letting his heavy cock fall over Izuku’s pussy, he grips at where his knot would swell and massages for a moment. It urges the knot to the surface, begins the process. Trailing his other hand away from Izuku’s neck, he trusts the omega to stay put and paints a little swirl in the mess on Izuku’s lower abdomen, over his womb. It doesn’t mean anything, the shape, but the motion soothes a lot of Izuku’s heat craze. Alpha will breed.
Izuku licks his lips and cups his flat tits. Perfect. He croons, just for Katsuki, showing off his low, throaty voice.
“Beautiful,” Katsuki rumbles back at him, an alpha singing to his omega. His chest vibrates with it, the deep, deep noise most alphas couldn’t even make at all. Dragging one of Izuku’s hands away from his own tits, Katsuki puts his teeth into his wrist gland. Bites hard, savaging the skin, the flesh, until there’s blood.
Katsuki’s an enigma.
The quirk sent him into rut, but released his enigma mind, the one that bridges Katsuki's alpha with his conscious thoughts. Enigma can think, pursue, and outrun his alpha. Enigma is dominant over all and anything. Enigma has chosen his mate, and nothing and nobody would ever be able to remove Katsuki from Izuku’s scent now. It would not fade, it would not weaken.
Slow, savoring the glide of wetness and the way Izuku's body bends and accepts every ridge and vein, Katsuki slides his cock into Izuku once more all the way to the root. Katsuki licks one of his engorged canines, enjoying the fighting stretch it took to shove in the slowly swelling knot.
As he pulls out, Katsuki enjoys the way Izuku’s pussy strains to hold on. The way it bulges outwards as he pulls his knot free.
He fucks faster, harder, careful at this point to bounce against his knot instead of making it rip through his omega. Enigma knew what to do. Could hold himself back until it felt so, so good.
Didn't need to hold back any longer.
Crouching down over Izuku and bunching the omega's legs up underneath his arms, Katsuki growls, savage, mindless. It makes Izuku gasp at the sudden immensity of his cock bullying his little cunny, and Katsuki hovers their faces close together. If they kiss, it’s in the way of animals, tongues out and licking, spit shared and drooling over freckles to one side and the other. Katsuki fills Izuku’s mouth with his tongue, then pulls back and bares his teeth in one final reminder of who owned him.
Izuku’s eyes roll back, his clutch threatening to catch.
Katsuki snarls because his knot was inflating, and it wasn’t inside yet.
He fucks forward, shoving onto his feet and toes, using his whole weight and forcing his omega to accept it or be crushed. His knot shoves into that cunt and Izuku’s clutch locks them together.
They climax, Izuku at the moment of clutch when his pussy spasms, forming a seal around his alpha’s knot, and Katsuki when it swells to it’s fullest, pressing tight and aching to Izuku’s pelvic bones.
Omega cries out, savaging at Katsuki with his claws. Enigma grins in victory at the evidence of his omega’s pleasure, he’ll bear the marks proudly.
Alpha howls when he comes, gripping at whatever is under his hands, thick strong leg and green hair, and gushes seed out of swollen balls, filling his omega’s womb, his cunt. Izuku bodily shivers, his insides fill and continue to fill. The smell of them, of pheromones and slick and come all mix throughout the empty building, a warning and a threat to any who may make the mistake of passing by.
Idly, Katsuki tests the clutch and rumbles in approval when nothing slips out, not a single drop of seed. Izuku makes a noise of displeasure, not liking the shifting and pulling of the tie. He clutches Katsuki tight, legs parted around his middle and ankles crossed behind his back. Sinking down, heavy with the trailing finishes of rut, Katsuki smothers Izuku entirely with his body, mouths smeared together in something that might be a kiss.
“Kacchan.” Izuku croons when his brain remembers he can speak. It's almost desperate, with an edge of omega euphoria too powerful to contain. “Kacchan. My Kacchan.”
“Shh, shh,” Katsuki will sooth, petting his fingertips over Izuku’s eyelids, drawing the lines of his mouth. Izuku licks at the fingers, purring.
When the knot deflates, Izuku whines at the sudden leakage. Shushing him, Katsuki paints their mixed juices into the drying mess over Izuku’s belly, leaving a handprint right there over his stomach where a child would swell.
In between nuzzles and small hushed whispers. Katsuki wraps Izuku up in his arms and warms him up. The summer night wasn’t cold, but the building was drafty.
He will knot twice more, to be sure his seed catches.
~
~
~
Some unspecified amount of time later, Izuku is waking up in one of the better hospital heat rooms (familiar, very familiar, safe, because enigma-alpha’s scent is right here, right next to him), and finds red eyes spearing into his soul.
“What did you promise.” A dark voice, heavy.
Consciousness clicks together. Memories hint at a sex-filled heat in the most primal of fashions. His wrist is wrapped in bandages.
“I promise I wanted it,” Izuku blinks sleepily, bleary and sore but sated, so sated. “I want you. I love you.”
All the tension in Katsuki’s body seeps out, and he crushes Izuku to his chest. Their kiss is gentle, a fierce contrast to the last few days.
“You stupid fuck.”
“Sure am. Sorry.” Not sorry.
“Stupid, stupid fucking asshole, why do I love you so much, you goddamn. I don’t even know what to call you. There’s no way you’re not pregnant, there’s no way that didn’t catch– don’t you fucking purr at me! I’m mad at you! I’m furious! Don’t you purr and, and, croon like that, you. You’re. Hmph. Fuck you.”
Izuku does continue to purr, one hand joining Katsuki’s on his lower stomach, rubbing his cheek affectionately against a strong shoulder.
“You cute motherfucker.”