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Katsuki reeled backwards, dodging the fist flying at him as he clenched his own and threw it back. It thudded satisfyingly against Kirishima’s hardened chest and Katsuki felt a grin spreading as he wiped the sweat from his face with the back of his hand. Kirishima grinned right back at him as he righted himself and raised his fists again. They’d been going at it for so long, both of them sweaty and out of breath, but neither wanting to stop.
Katsuki took a punch to the gut, skidding backwards a step as his stomach rolled, but he simply huffed a ragged breath before launching himself right back at his best friend with a shout. He lived for this shit. He smashed his fists into Kirishima over and over again as he worked through his pent up energy. The past couple of days he’d been on edge, angrier than usual, and restless in a way he couldn’t explain or even quite pinpoint. He’d had trouble sleeping and concentrating, so Kirishima had suggested they fight until he was spent enough to finally get some rest.
Katsuki had of course taken him up on the offer. His best friend had always given as good as he got.
Katsuki licked the seam of his lips as the redhead came charging back at him, throwing up an arm to block a vicious punch before hitting out with one of his own. He knew Kirishima probably didn’t have much left in his quirk reserves, so he doubled down and focused on breaking his friend’s defence. He was gonna fucking annihilate him.
He almost hesitated for a moment when the back of his skull twinged and buzzed oddly. Did he want to annihilate the pretty redhead?
Katsuki could smell the sweat that sheened his best friend’s body much more than usual. He clenched his jaw and ground his teeth as he dodged another punch and grabbed Kirishima, twisting to throw him bodily to the mat and follow him down, assured of his victory as he pushed the redhead’s face into the mat beneath them.
A pleased grunt followed by a huff left him as saliva flooded his mouth.
This seemed right.
The urge to lean down and bury his nose in the back of Kirishima’s sweaty hair had him scowling. The fuck? He drew back, popping to his feet quickly to get away from the faint scent. He’d never smelled his best friend’s pheromones before, he was an unpresented. The fuck was that about?
Katsuki’s mother was an alpha, but his father was an unpresented, like him, and he’d been hoping a presentation would never be something he had to deal with.
It was nothing. It was obviously nothing.
He shook his head to clear it and swallowed a mouthful of saliva. Ugh, why was there so much spit in his mouth?
Kirishima gasped in several breaths, rolling over to splay out on the cushioned sparring mat. His hardening faded away as he propped himself up on his elbows. "Damn," He panted, looking over at Katsuki as a grin split his face. "You win this round. Are you feeling any better now?” He asked as he climbed to his feet and rolled a shoulder to loosen it.
“I- I don’t fucking know.” Katsuki admitted, scrubbing a hand against his trousers to dry it before wiping his face. He felt weird. Really fucking weird. He’d thought sparring would tire him out, make it so that he could finally relax– but it had just made him more antsy. His skin felt hot and tight, and he wanted to both run away from Kirishima and get closer to him. He could fucking smell him in a way he’d never thought possible, and it was starting to kind of itch at something in his brain. Katsuki wasn’t stupid, he knew something was up, something perhaps wrong, but he steadfastly pushed the thought of presenting back into the recesses of his mind. The whole ‘pheromone’ thing just seemed like a big fucking liability to him, and the idea of scents affecting people, affecting him specifically…
No. No way. Nuh uh. Nope.
Katsuki chewed at the inside of his cheek, lost to his thoughts and that odd internal itching now trying its best to fray his nerve endings to all hell, until the light clap of a rough hand on his shoulder had him snapping back into the real world like an over tensioned elastic band.
His head shot up and his entire face heated at the concerned look on his best friend’s face. Pretty. Strong and pretty. He stepped back with a grumbled out suggestion that they shower and head back to the dorms. He needed the redhead to wash away that fucking smell.
Kirishima was a beta. Katsuki had heard that beta’s didn’t usually have strong scents or pheromones, but there were enough variations within each presentation group that most second-gender stereotypes were exaggerated at best, and downright insulting bullshit at worst. Maybe the redhead had just foregone deodorant today. That was probably it.
Kirishima said something and laughed at what was probably a lame joke, but Katsuki was too in his own head to pay attention as they loped through the back of the gym and headed for the changing rooms. Everything would be fine once his best friend had showered Katsuki told himself, shouldering the doorway accidentally because he hadn’t been watching where he was walking.
A low growl burst from him before he even realised what he was doing, teeth bared at innocent wood.
“Woah, dude! What the– you okay there?” Kirishima asked, a concerned frown pinching his brow as Katsuki swallowed the growl down and fought an embarrassed flush. Tanned nostrils flared as Kirishima sniffed the air, even leaning closer until Katsuki stepped away quickly. They stared at one another for a long awkward moment, until the redhead cleared his throat and asked if Katsuki wanted to maybe watch a movie later, in one of their rooms, just the two of them.
Alone, alone, alone…
“Sure. Whatever.” Katsuki bit out, yanking his towel and toiletries from his gym bag, before marching into a shower. He shot his best friend a sidelong glance that was met with a reassuring smile, and huffed a breath as he closed and locked the cubicle door.
Katsuki was losing it.
The entire time Kirishima bathed in the stall next to his he found himself fighting the urge to invade his shower and…force him down? He almost acted on the compulsion when he heard a singular appreciative moan a few minutes in, but managed to keep himself in check, gritting his teeth as he aggressively scrubbed himself clean.
Katsuki wasn’t dumb though, he knew something was up with him, and it was looking more and more like he might present by the minute. The three year long secret crush he’d harboured for Kirishima could royally fuck up the best friendship he’d ever had if he wasn’t careful. He could almost feel his, ugh, feelings clawing at the inside of his goddamn head.
He needed to get away from the redhead, lock himself up in his room or something until whatever this was either subsided or took over, whichever came first.
Katsuki showered and dressed as quickly as possible, his heart doing funny things in his chest when his best friend joined him at the lockers before he had the chance to flee. He found himself staring as Kirishima pulled a soft blue shirt over his head. He wanted to rip it right back off the man and sink his teeth into perfect tanned flesh.
Katsuki gulped and wrenched his gaze away, a low growl rumbling in his chest in a way he was sure it hadn’t been capable of doing before. Kirishima’s cheeks flushed a pretty pink at the sound and he swallowed thickly too, but didn’t say anything.
Katsuki stared.
He caught himself and snatched up his bag, marching outside. He had to get back to the dorms before he turned into an animal. He’d heard the stories. Exaggerated though some of them likely were, he had a feeling he was about to present as an alpha.
“Hey, wait up!” Kirishima caught up to him easily and Katsuki’s top lip curled up in a silent snarl. Fuck. Fuck. “You feeling okay, man, you smell kinda…oh. Ohhh. Shit, Bakugou, we should probably get you somewhere safe, you’re…mmmm…” the redhead trailed away and Katsuki felt the air beside him thicken and change, the scent of petrichor suddenly filling his nostrils. His body tensed all on its own, muscles clamping down on bone as he halted abruptly.
That scent. He sniffed, filling his lungs as he fought a groan. Fuck. He– he needed–
“Shit–” he bit out as a searing pain zinged up his neck to the underside of his jaw. He reached to clasp a hand against it as his body practically vibrated. “The hell?!” He hunched forward with a snarl, baring his teeth against the pain and need suddenly coursing through him.
Mate... The word whispered through his mind and he knew. He could feel it. Kiri– no, Eijirou was his. His. He turned back to his best friend, eyes blown with both confusion and sudden desperation. The redhead stared back at him as he pressed a hand over his own scent gland, likely in an attempt to stem the flow of his pheromones and stop them from making Katsuki’s sudden presentation worse.
Eijirou dug his nails into the skin of his neck, knees almost visibly wobbling as Katsuki chuffed and tried to catch his breath. "B-Bakugou?" He managed to stutter out, taking a step forward. "Y-You're presenting, man. We have to–" he paused, clenching his teeth together to suppress a shiver, "–oh wow, your scent is strong as hell, what the–” he shook himself out of it, “–we have to get you to your room!” he finished with effort.
Before Katsuki could even register what he was doing, he grabbed Eijirou by the front of the shirt and shoved him back into the wall beside them. His blood pulsed hot and thick through his veins as he bared his teeth at the redhead, catching himself just before he could sink them into perfect skin to mark.
“Fuck, sorry. Sorry, I’m–” He screwed his eyes shut, trying to force himself to breathe through it. Eijirou’s scent filled his lungs again as he drew in a ragged, shaky breath. Fuuck. His fingers twitched but he loosened his grip with willpower alone, desperately trying to ignore the clearly shocked moan that had slipped from his mate’s throat.
His…mate?
His fucking mate.
“You– you gotta run.” Katsuki bit out, dropping his hand to clench it into a fist at his side as he let his forehead thud against his best friend’s shoulder. “You gotta get away from me, Eijirou...” he didn’t know how much longer he could fight the urge to fall upon the redhead like the animal he was clearly becoming.
“My first name?” Eijirou drew in a shaky breath of his own, and Katsuki tilted his head towards it, watching his best friend’s Adam’s apple bob in a heavy swallow.
“I like you.” Katsuki whispered, but it sounded more like a low purr, “have for years, ‘n I think it’s fucking with whatever instincts I’m getting right now. I’ll fuck you if you don’t leave.” His tongue was out of his mouth before he could command it to stay put, and Eijirou’s skin tasted delicious.
“I– oh god…” the redhead whispered, and Katsuki could have sworn the man almost trembled at his words. He purred.
He’d never been able to purr before.
Katsuki’s neck throbbed, the slit that had just torn its way through his skin pulsing as it pumped his new pheromones out, thick and heady. He didn’t know how to stop it. He didn’t know how to gain control over the situation, or himself, and he groaned in frustration. The only thing he knew was that he needed Eijirou, needed to touch him, grab him, fuck him.
Claim him.
“If... If I have to run…” Eijirou started, voice hoarse enough to crack, “…then you have to chase me. Catch me and I’ll–I’ll let you do whatever you want. Hunt me, alpha. I really want you to hunt me like an omega…”
Chase me.
Hunt me.
Katsuki felt Eijirou’s words like a brand inside his brain. Chase him, hunt him, fuck him. He drew in a sharp breath and took a forced step away, eyes searching his best friend’s face for confirmation. He could smell what he was now sure was arousal. Eijirou wanted him too.
They could talk about this later.
“Run.” He bit out; a command he’d heard about, but never been able to use before.
Eijirou shivered, then shoved himself off the wall into a sprint without a backwards glance. He pelted across the grounds, his gym bag abandoned on the path where they’d stood.
Katsuki watched his soon-to-be mate tear away, fists pumping as he ran like the prey he’d just made himself. He held himself still for what felt like eternity, jaw clenched as he counted every second. When it looked like the redhead might actually get away, he dropped his own bag and took chase.
His senses were heightened, every colour and smell more vivid, vibrant. The air whipped past him as he pumped his arms, carrying the scent of the grass crushed underfoot, the distant waft of cooking…and his mate. Katsuki had never felt more alive than he did right then, as he pushed his body further. Faster. Eijirou wouldn’t get away from him.
His perfect prey.
He saw the redhead dart into their dorm building and gave a breathless growl as he pushed himself even harder. He slammed into the door, wrenching it open to throw himself through it. He could smell him. He bolted through the common area and toward the stairs.
Eijirou ran past his classmates, ignoring several exclamations of surprise when he shoved a couple aside. Katsuki didn’t need to see his face to know he was single-mindedly focused on getting upstairs, on minimising the chance of them being broken apart.
Good mate.
The redhead skidded into the elevator down the hall and the doors slid shut just before Katsuki could get in, so he darted for the stairs instead. There was saliva dripping down his chin and he knew he probably looked rabid, judging by the way his classmates had recoiled away in the common room.
Didn’t matter.
Katsuki didn’t even think to use his quirk as he bolted up to the fourth floor.
Eijirou was fumbling with the keycard to his room, barely managing to scan it in time as Katsuki barrelled right into him from behind and took them to the floor. They landed in a breathless heap and Katsuki shoved a hand between broad shoulders, scrambling to straddle the redhead’s ass and rut his now fully hard cock against it frantically through their clothes.
“H-holy shit!” Eijirou gasped, both hands hardening to drag them both forward bodily, before attempting to kick the door shut so it would automatically lock. Katsuki dropped down over his mate, mouth open as a line of drool hung from the center of his bottom lip until it snapped, landing in the back of red hair.
“Fuck Ei. No one's gonna save you now.” He groaned out, shifting to grip the back of the redhead’s hands as he screwed up his face against the burning friction of the clothes between them. Claw-shells grew over his nails, stinging as he mouthed messily at the back of Eijirou’s neck.
He was gonna cream his fucking pants humping his best friend in the world like a wild dog on the floor, and he couldn’t find the willpower to stop himself.
“I don’t wanna be saved, Katsuki,” Eijirou panted as he shoved his ass back as best he could, “I wanna leave this room with a goddamn claim, I think I’ve waited long enough for you to return my f-feelings.” He choked on a gasp when Katsuki thrust down so hard at his words that they moved a couple of inches across rough carpet.
Eijirou squirmed to pull an arm free of his grasp, and Katsuki’s instincts went wild thinking he was trying to escape, but the redhead simply shoved that hand beneath himself. He fumbled for a moment before a moan of utter pleasure broke from him and hisarm began to jerk rapidly as he rocked his hips back.
Oh fuck.
Heat coiled immediately in Katsuki’s gut and the base of his cock began to burn and grow in confining cotton at the realisation that his mate was touching himself while being practically ground into the floor.
“You promise?” Katsuki gasped, release warring suddenly with the urge to claim, and the need to check if his beta would allow it. “You promise you won’t regret t-this?” His voice broke and then pitched straight down two octaves as a real alpha rumble rattled his chest.
“Do it already! I’m gonna-” Eijirou’s jerking arm stuttered, and Katsuki felt his instincts take over at the weaker beta command.
“Mine.” He snarled, claiming fangs snapping from his gums to pierce tanned skin and tie them together as he unloaded everything he had into his pants, new knot pulsing and throbbing until wetness forced its way through material to drip between his perfect prey’s legs.
His perfect mate.