Chapter Text
Katsuki doesn't mean to bite into the half and half bastard's mating gland. He'd meant to tear his throat out, mad with grief over a fellow hero lost to the LoV. Yet here he is, feeling a bond snap into place with Todoroki fucking Shouto, omega villain.
The fight had been vicious. Canines flashing and spit flying, ferocious snarls travelling back and forth as they both clawed at one another with bloodied knuckles. Shouto was usually untouchable, using his quirk to stay well away from any hand-to-hand combat. But Katsuki was fueled by grief this time, and somehow he managed to finally get a hold of him. Somehow, he actually caught him mid-air, dragging him first by the leg and then by the scruff of his neck until he had the slippery little fucker flat on the ground.
There was no way he was letting him get back up after that.
They grappled, Katsuki rolling and grabbing and pinning each time the bastard tried to wriggle away, because Shouto was as strong as he was cunning, and not just for an omega. It would’ve taken him only a second to use a lapse in Katsuki’s judgement to his advantage and escape. So he stayed on him, keeping him as close to the ground as possible. He still nearly tumbled Katsuki off of himself time and time again, somehow resisting the alpha snarls that would make any other omega submit and bare their neck in a heartbeat, until Katsuki eventually got him firmly and undeniably pinned.
His gloved hand tightened in Shouto's hair just above his scar, and it made the omega finally shriek. The cry nearly made Katsuki lose his composure, something so purely omegan in it as the sound battled against the instincts of his inner alpha.
But he didn't let go, and another fiery rage built in him instead. Shouto must have shrieked on purpose, using his omega wiles to try to make him relent. It was the sort of tactic Katsuki always had thought was beneath someone like Shouto, but clearly not when it came to life or death.
He bared his teeth, deciding he needed to end it, now. He leaned down, ready to do the unthinkable in order to avenge his friend, canines brushing skin. His hand tightened in Shouto's hair as he growled, Shouto crying out again, kicking, squirming, until finally Katsuki bit down, just as the body beneath him twisted—
The thin plastic he met was nothing compared to his fangs, torn in an instant, hot blood pooling in his mouth as Shouto stopped moving. No, as they both stopped, a rush of endorphins bursting between them, through them, Shouto gasping in a sharp inhale of breath.
Something clicked, in that instant. Suddenly, he could hear Shouto's heartbeat thumping in his own ears. He could smell his scent, the plastic blocker on his neck thoroughly destroyed, the homely scent of him invading Katsuki's nostrils for the first time.
And he could feel the shooting pain in the scar adorning the omega’s bright blue eye.
Which all lead him to now, his teeth in Shouto’s gland, a bond snapping firmly into place between them. Katsuki tries to withstand it, but his will might as well be butter with how easily the bond pierces through it. His grip on Shouto's hair releases entirely, his teeth jerking out from the place he’s carved on his neck. The omega rolls away from him as soon as he's able, his back slamming against a nearby wall as his hand clasps over his bleeding throat.
The first thought that springs to Katsuki's mind is that he needs to clean the bite. That he needs to help it heal by using his alpha saliva, full of antiseptic properties just for this very reason.
The second thought he has is oh, fuck no. No, no, no.
Because that means that really is now his mate who’s sitting across from him, and all of his instincts are screaming at him to do his duty towards this…this villain. Shouto's chest heaves where he's pressed himself flat against the wall, his eyes cold and downright murderous as he bares his omega fangs. "What did you do?"
Katsuki stares back at him, heart racing. He can still taste the omega's blood in his mouth. It must be smeared all over his lips.
"I didn't—" Katsuki starts, faltering before feeling anger surge. "You moved your damn neck! It wasn't my fault!"
Shouto scoffs. "You bit me. You're an alpha, I'm an omega. What did you think was going to happen?" Katsuki watches as the omega shakes his head, expression incredulous. "If you did this because you think it will somehow make me go easier on your hero friends, you're wrong."
"Oh, please," Katsuki all but spits. "As if anyone would ever mate you on purpose."
Something weird happens then. Shouto's expression doesn't change, as stoic and cold as always. But Katsuki feels the impact of his words, how they hit Shouto somewhere sore.
Oh, god. He can feel it through their bond.
What the fuck has he done?
"Stop," Shouto bites out, less harsh this time. "Don't you dare pity me."
Katsuki doesn't think anything showed on his face either. Which means that Shouto must have felt that through the bond, too. It's strange. It's not like he can feel Shouto's pain like he'd feel his own. But he can pinpoint the areas where he hurts, and it's almost like he can feel the strange throb of it somewhere in the back of his mind.
It's driving his alpha fucking crazy.
Shouto's eyes are growing tired. Katsuki can feel that the throb is behind the omega’s left eye, leading up to just under his hairline, where Katsuki's fingers had gripped and twisted his hair. He hadn't realised that the scarred skin there would be so sensitive. He thinks back to Shouto's shriek. Katsuki had thought he was faking it. That he had been using an omega trick to appeal to Katsuki's alpha instincts. He hadn't. His cry of pain had been genuine.
Katsuki feels sick.
The other throb he feels is obvious, rabbiting with Shouto's heartbeat beneath the omega's palm where it sits pressed up against the mating bite. Mating bites aren't easy. That's why they're supposed to be done in a nest, preferably while the omega is distracted by, well...more pleasurable things. Then the wound is supposed to be tended by the alpha's tongue, the quickest method of healing, all while the omega rests and recuperates from having a fucking bite taken out of them.
But here Shouto is, out on the cold dirty asphalt.
Katsuki can feel how Shouto's strength is waning, only because his alpha is becoming more and more erratic, pressing at him to protect him. To take him and scent him neck-to-neck, until all the fear washes away. To bring him to his nest, wherever that is, and comfort him.
To bring him inside somewhere, away from any other alpha's prying eyes, alpha's who might smell a freshly bitten omega in distress and try to have a go at them themselves. Because Shouto is growing more distressed, even as he tries to keep a brave face.
But he isn't the only one afraid. Katsuki is afraid too. He just mated a villain. His enemy. One who may have had a part in killing his friend—
Katsuki averts his eyes, fist clenching. Then he finally stands.
Shouto shuffles back, eyes wary. Katsuki only digs around his belt. He tosses a roll of gauze at him, Shouto eyeing it skeptically as it bounces and lands beside him.
"Clean that up," Katsuki says, voice raw, "and get the fuck out of here before somebody finds you."
With that, he turns and leaves, ignoring the desperate howls of his alpha. He booms through the sky, the rush of wind in his face at least a distraction from how strange he feels. He’s concerned, knowing his omega is hurt. Stressed, knowing his bite hasn't been tended. Hollow, knowing there's nothing he can do about any of it. It’s all so fucked up. He shouldn’t be worrying. Not for him. Yet here he is, doing just that.
Shouto's aches throb dully through the bond, and all Katsuki can do is wait for him to get help. For someone to patch him up. For him to get into his nest and recuperate. He can still feel how unsettled Shouto is, but he knows that omega's nests help them to regulate. So he waits, and everything else he does that night comes second to it. Showering, brushing his teeth. Trying to eat something. It all passes in a blur, Katsuki's focus on the bond he can’t quite ignore.
Soon, he's lying in bed, still waiting for Shouto's to settle through the bond. Yet the hours pass by, and still it persists. Katsuki lays awake, blinking at the red lines of his alarm clock as they change from three, to four, to five a.m, all while Shouto still aches through the bond. All while he remains unsettled and distressed.
"What the fuck?" Katsuki finds himself murmuring.
Days later, and no change comes through the bond. Shouto is still distressed and wound tight, while Katsuki feels like a goddamn zombie.
He's been making rookie mistakes on patrol, his mind constantly split between what's happening in the present and what's happening through the bond. Even now, writing reports in his office, he can't focus. Not with this stupid fucking thing keeping him on high alert. His conversations with his friends are mere grunts rather than any actual speaking, too. He can't go to them for advice, or for solace. Even if he could, he wouldn't know how to tell any of them about what happened with Shouto anyway.
What would he say? Oh, by the way, I've mated the villain who killed Edgeshot?
The man who saved Katsuki's life. Their mentor. Their friend.
Even thinking about it makes Katsuki feel sick. But his omega's distress through the bond makes him feel sicker. The bond will only strengthen over time, and he needs to find a way to break it before that happens. But how can he, when he can barely pay attention to anything but the bond?
God, why can't Shouto at least do this one fucking thing? Why can't he just get in his fucking nest and sleep or rest or take a minute away from being stressed? He's got to have one in one of those shitty hideouts the LoV are always moving around from. Unless...unless actually, maybe he doesn't. Now that Katsuki thinks about it, it's more than likely Shouto doesn't have a safe enough place to nest in. How could he, when they always moved from place to place? He doesn't recall ever seeing a nest in any of the hideouts they raided.
The realization makes him punch his office wall.
"Fuck!" He growls out, before punching it again. "Fuck, fuck, fuck!"
So his omega is just in a perpetual state of anxiety, then? Along with his scar, still throbbing through the bond days later. He's just always in pain, too? God. Katsuki has no idea what to do. He needs Shouto to take care of himself. He needs this bond to fade away into nothing instead of constantly screaming at him.
He needs to stop remembering Shouto’s scent in the middle of the night, warm and sweet and comforting, like walking into a bakery.
His phone ringing is what pulls him from his thoughts. He glances at the screen before answering with a snappy, "What?"
"Dude," Eijiro says, and there's something about the way he says it, almost giddy. "We've got him. He's cornered. You have to come, now."
"Who?" Katsuki asks, dread pooling in his stomach. He knows who. They've all been looking for him. That's why they’re ringing Katsuki now. So that he can be the one to bring him in. So that he can be the one to get justice for Edgeshot.
"Who do you think?" Eijiro answers. "Shouto Todoroki."