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Izuku, no, Deku had always been there with him. Katsuki obviously was born first and presented first, always walking ahead. Clearly things would never change.
“It’s already a week after your birthday. Stupid Deku can’t even present on time,” Katsuki scoffed annoyedly.
“I’m sorry, Kacchan I can’t really do anything about it,” Izuku pouted, his legs swinging in the air before he jumped off the swings.
“You gotta be able to scent me too! School sucks like this! Idiot– Stupid–” Katsuki snarled. Deku dared to look at him apologetically, but he was so pissed off.
School was torture. All the scents around were making him sick and stupid. Deku was supposed to scent him when that happened. That’s what the books said. Your mate would be the one to soothe you among the soup of scents in this world. Family was also an option, but Katsuki was not taking more than a quick nuzzle before school. There was no way he was going to smell like his parents. He was not a baby.
—
Deku finally presented a month later. To Katsuki’s shock, Deku was also an omega.
Very quickly, he decided it didn’t matter. Deku could now scent him. It didn’t keep all alphas at bay at first, but Katsuki could start to smell the possessiveness in the scent soon. That made most other people avoid him, which then made his omega preen.
Good. He had been scenting Deku heavily for months now. People had not dared to come too close. Deku was an idiot who sometimes whined that other kids didn’t want to play with him, yet Katsuki was proud of his work.
Idiots should keep away from his Deku.
—
Deku smelled too much like a fucking alpha. The scent got into his nose; it was a violent push into his nostrils, it stung his skin and made everything feel so wrong. He couldn’t explain it. When he looked at Deku and smelled him now he couldn’t think. His omega yelled at him to rip apart the alpha, but there was no one else but them.
Katsuki’s fangs ached. He couldn't keep his mouth shut when saliva kept pooling up. Even touching his fangs with his tongue made him hiss over the feeling. Was he leaking venom?
“K– Kacchan? Did you just growl?”
“What if I fucking did Deku? Shit, give me a minute.” Katsuki took a step, his feet dragged him straight up to Deku. His nose took in the scent, trying to find the source of the omega under the disgusting alpha musk.
“U-um, that tickles,” Izuku laughed a little, but didn’t push Kacchan away. He liked their scenting sessions, even if Kacchan was acting a little different.
“Stupid Deku. Doesn’t even smell like you– it’s disgusting, it’s—” Katsuki growled. A delicious whine left his lips instantly after his nose found the spot.
Deku’s scent gland.
His body relaxed a little, tongue coming out to lick at the slightly elevated skin. He’d never really tasted Deku before, but right now he couldn’t stop. The boy’s scent was intoxicating. He needed more, needed their scents to mix to drown out the disgusting smell of alpha.
With a few licks Katsuki was gone. His lips were slick with the oils from Deku’s gland, yet his omega wasn’t satisfied. It desired to have all that Deku had to give.
Katsuki was getting closer and his legs now straddled the other boy's. “Izuku,” Katsuki whined as his hands roamed on top of Deku’s clothes. Searching for something, but he wasn’t sure what. “Scent me you… Bastard.”
Katsuki was panting, a deep purr reverbated from his chest when Deku scented him back. Deku’s wrist moved to every available piece of skin it could find from arms to back of the neck.
“Is this good Kacchan?”
“More. You stink.” Katsuki reluctantly moved his head away, his lips shining from the oils. Izuku couldn’t look away even when the other omega tugged on the hem of his shirt. “Off.”
As Izuku got his shirt off Katsuki smelled it. The scent of alpha was so strong in Izuku’s shirt, right on his nose that he saw red. His fangs ached, he could taste the venom and all he could think of was one word. Mine mine mine.
Katsuki bit into the shirt, ripping it with his teeth. He couldn’t hear anything, nor register what was happening around. All he needed to do was protect what was his.
When he was sure that the alpha was beaten, Katsuki growled his one track mind, focusing on Izuku’s scent.
Mine. Teeth sank hard to Izuku’s shoulder.
Katsuki wasn’t sure what had happened, but he felt relaxed and more alive than ever. His emotions were a mix of confusion and happiness. He could taste blood and oil in his mouth.
He was still sitting on Izuku’s lap, but the alpha stench was gone. All he could sense now was something new. Mixed scent of him and Izuku, but with a hint of something that had not been there previously. And he loved it.
Our scent. His omega provided.
Katsuki purred as he let go, his tongue darting out to lick at the bleeding wound on Izuku’s scent gland instinctively. His omega was pleased and over the moon.
“Kacchan?” Izuku said with a hazy voice.
“Mm,” Katsuki hummed into Izuku’s shoulder, before sitting back. “What nerd? Better be the last time you come here smelling like that. You’re mine now.”
Izuku looked at him for a bit, before his eyes opened fully. Katsuki saw how the boy's face turned red and it made him smirk.
“H-huh? I’m Kacchan’s– What? That’s–” Izuku couldn’t get a full sentence out. Katsuki grabbed Izuku’s face with his hands and looked straight into the boy's eyes.
“You got a problem with that, huh nerd?”
“N-no.” Izuku shook his head the little he could. “I’ve always been Kacchan’s.”
Katsuki’s smirk widened as his scent bloomed. “Thought so.”
“Can I,” Izuku gulped, eyes darting down to Katsuki’s neck and back to his eyes. “Can I bite Kacchan too?”
Katsuki’s ears heated up in a second, his heart beating faster in response. His omega reeled with happiness. Yet he bit his lip just so he wouldn’t too eagerly say yes.
“Kacchan?”
“Tch. Whatever. Guess it’s only fair,” Katsuki mumbled, trying to sound as nonchalant as possible.
He pushed down his shirt a little, revealing his gland fully to Izuku. Katsuki leaned his head to the side, giving the other omega space.
Izuku’s teeth were bigger than his, a little scary, yet the thought of having those fangs on him was exhilarating.
Izuku moved so slowly that Katsuki whined in anticipation. Just as Izuku’s breath touched his skin the door behind him slammed open.
“Katsuki!” his mother yelled and before he could even realize what was happening he had been lifted from Izuku’s lap.
“You kids, what is all this? Izuku you shouldn’t–” Mitsuki gasped when she realized what was on Izuku’s neck. Clear teeth marks.
“I’m going to get Inko. And Katsuki you’re coming with me. You will not see Izuku for the time being.”
“But mom,” Katsuki whined. His omega was whining way harder since he was being kept away from his mate. Katsuki knew that mate had to be referring to Izuku, because that’s who he wanted to get close to. Right away. “Let me down,” Katsuki thrashed around, trying to get out of his mothers hold.
When the slight distress scent hit Izuku’s nose he was already lunging at them, fangs bared and scent angry.
Mitsuki reacted just in time, shutting the door and leaving Izuku to Katsuki’s bedroom. Growling, confused and alone, without his mate.
—
After that day Katsuki didn’t even see Izuku at school. A few weeks passed and he grew ever so frustrated day by day.
“Why can’t I meet Izuku? Where is he?” Katsuki growled at his parents.
“Well. Apparently the bite you left isn’t fading like it should so we’re keeping you separated till it does,” Mitsuki explained. “You stupid brat shouldn’t have bit him. He’s an omega. You might have ruined everything for him now. He might not be able to ever get an alpha when he's bonded already.”
“Good!” Katsuki snarled. “He should only be bonded to me! Izuku is my mate! He wants to bite me too so let him!”
“Absolutely not! You’ll thank us later for this honey. You’re going to get an alpha like it’s supposed to be,” Mitsuki slammed her hand on the table.
Katsuki bared his teeth growling at his mother. He couldn’t believe this. He’d be with Izuku no matter what. He didn’t want no stupid alpha, nor did Izuku. Izuku wanted to bite him. Izuku was his and he was Izuku’s.
His omega agreed fully and even if Katsuki didn’t like it when his omega tried to sway his thoughts, he liked it when the bastard agreed. And with Izuku it had never been wrong.
That night he tried to sneak into the Midoriya’s only to realize that the house was empty.
A sense of dread covered his entire being and Katsuki couldn't breathe. His omega wailed and clawed at his insides, begging for his mate. Somehow even when Izuku didn’t bite him yet he felt miserable.
He wished they didn’t get interrupted. He wished Izuku had bit him so he’d know how the nerd was feeling. Is he okay? Would he come back?
Katsuki laid down into Izuku’s bed, clutching his legs against his stomach. Everything hurt. His parents were stupid. Auntie was stupid. Izuku was…
A whimper escaped his mouth and Katsuki grit his teeth. He hated this.
How dare Deku abandon him like this?
A loud, agonizing whine escaped his mouth as Katsuki laid there on Izuku’s bed. At least his things were still here. It meant that he would come back, right?
Unaware and unable to focus, Katsuki didn’t notice the absence of sheets, or any smaller, personal items in the very bare room.
—
Katsuki’s second ever heat was pure hell compared to the first one. Now that his omega wanted someone, nothing worked.
Katsuki tried all the toys he used last time, also the new ones his old hag got him. None of them satisfied his omega. Even when he came, time and time again, he couldn't rest. It just wasn't enough.
When the third day started Katsuki was sure he was going to die. He hadn’t slept in two days. Only short naps, then his body awoke him yet again.
His parents kept bringing him food and water, telling him this is all normal.
Bullshit.
Katsuki whined, another wave of heat hitting him way too soon. He eyed at the clock, sniffling when only an hour had passed since the last wave.
He looked down at the changed sheets and breakfast on the table. His parents must’ve come again when he had been out of it.
He wanted to eat, yet his body demanded something else first. With a groan, Katsuki moved some blankets around, before he grabbed one of the way too many dildos his mother bought him.
Katsuki grimaced, his hole pulsing with need and slick pouring out involuntarily.
“Yea yea fucking needy bastard, I’ll get to it,” Katsuki huffed at his own body, laying down onto his back. His mind felt no joy, only the sense of duty to give pleasure to his stupid body seeking it.
Oh how he wished Izuku would be here. Katsuki whined as he pushed the dildo between his legs, letting it gather slick so it would be easier to push in. He imagined Izuku here, between his legs. His perverted little gaze on him, licking him, opening him up on his tongue…
“Oh fuck,” Katsuki whined, “ Izuku.”
“Kacchan?”
Katsuki perked up. His body was frozen in place, his already rapid heart beat getting louder in his ears as he waited. It took only a second before he got a whiff of the scent.
Izuku.
He couldn’t see the omega, yet he knew that somehow he’d snuck in from the window. Even the thought of that had his omega chirping happily.
“I’m so sorry Kacchan. I’m not supposed to be here. But I could feel you everyday, your distress and now–” Izuku’s eyes were half lidded, his mouth hanging open and he drooled. Katsuki should feel the need to kick the nerd for that, but instead he preened. The omega wanted him—was affected by his scent.
“Stop apologizing,” Katsuki panted as he flung the dildo as far from the bed as he could. He didn’t hesitate when he sat up a little, and opened up his legs wide to welcome Izuku to his nest. “And fucking help me. Mate.”
The possessive growl that left Izuku’s lips made Katsuki shiver. Oh fuck. He was glad his parents were already gone for the morning and left him things on the table. No one was going to stop them. And if they tried, he was sure Izuku would fight them.
Izuku got further in from the window. The younger omega didn’t hesitate anymore. It was clear instincts were taking over, and Katsuki purred as Izuku settled between his legs.
Katsuki cursed, when Izuku leaned down to kiss his jaw and licked his scent gland. Sharp teeth nibbled at the sensitive flesh and Katsuki bucked his hips up instinctively.
“Izuku… Please,” Katsuki panted, legs shaking from all the want. He’d been struggling for days. He didn’t want to wait any longer.
Katsuki watched as Izuku got up to his knees, ripped off his shirt and went straight to remove his pants too. He was glad the omega took the hint. Katsuki had been naked, wanting and ready for days. Just for Izuku.
When Izuku lowered himself back down, Katsuki moaned as a leg pushed against his leaking dick. He wanted to feel Izuku against him, in him, yet he let the other lead. He couldn’t help loving all the kisses his sensitive skin got, and the touches those rough hands gave him.
It’s exactly what he’d been craving. Everything finally felt right.
“Kacchan Kacchan Kacchan,” Izuku chanted as he kept sucking on Katsuki’s skin. Their hips slotted together in a new angle and their dicks grinded against each other.
Katsuki whimpered, so tender and sore from the past days. Izuku seemed to catch on, letting his hand travel down, only lightly touching until a finger found his entrance.
Katsuki was so wet he could feel the fresh sheets getting damp. Katsuki lifted his hips, confused mewl escaping his lips when the finger didn't enter him.
Katsuki opened his eyes to look at Izuku, who seemed to be as dazed as before. Yet he seeked permission. Those emerald eyes watched him intently, questioning, ‘Is this okay, Kacchan?’
A soft smile danced on Katsuki’s lips, as he lifted a hand to softly touch the omegas cheek. “Claim your omega.”
Katsuki was not sappy. So he said what he knew was enough. The words made Izuku lick his canines, and with no warning the finger finally slipped in.
His hands gripped the sheets hard as Izuku used his finger, soon three, to satisfy him. Katsuki couldn't help coming in mere minutes from the sheer joy of having his omega close.
Still it wasn’t enough.
Katsuki’s eyes were watery, filled with unshed tears. He lifted his legs up under his knees, presenting for his omega.
“Izuku.”
The delicious sound and display got Izuku moving at a record speed. His red, leaking cockhead was instantly pushed against Katsuki’s gaping hole. Katsuki could smell Izuku’s slick, the arousal in the air hung heavy as Izuku pushed in.
Katsuki moaned, letting go of his legs so he could hang on to Izuku.
It didn’t matter that some of his toys were bigger, or vibrated. Izuku was way better than any of them. The way Izuku’s cock dragged along his walls and filled him had his omega more satisfied.
The tears rolled out of his eyes as he gripped on Izuku’s back tightly. Sharp claws dug into skin, yet it only seemed to spur Izuku on. The movement of hips got faster, moans and slaps of skin filling the otherwise silent space.
Katsuki felt Izuku’s thrust getting needier, more demanding. The bites close to his gland were rough, Katsuki was sure he was bleeding, but he didn't mind. He just wished Izuku would bite him already. He wanted to feel what the other omega was feeling. Wanted to be his. Fully.
Chants of their names filled the air, Katsuki baring his neck. “Izuku, Izuku, close–” Katsuki panted.
“Kacchan, Kacchan, mine–” Izuku breathed heavy into his neck. “Gonna be mine.”
The obsessive voice had Katsuki almost come on the spot. “Yes, yes Izuku, y-yours.”
And when the sharp canines finally sank into his over sensitive gland he came with a loud moan. Izuku latched on like Katsuki was his last meal, while his hips stuttered and he came inside.
There’s no knot. Yet when Izuku bit down onto him, breathing hard, not letting go, Katsuki's omega cheered.
It took a few minutes until Izuku let go. The bite hurt, it was way deeper than the one he gave Izuku. Yet the burn made him feel good. Complete. And when Izuku pulled out Katsuki purred, loudly. It wasn’t only his own satisfaction on his mind, it was Izuku’s too.
Neither of them spoke. Izuku started to lick his gland and Katsuki saw the blood on his lips. The omega traveled down, licking, cleaning sweat and cum from Katsuki’s skin and he preened from all the care.
“Enough,” Katsuki finally huffed, pulling Izuku towards him to lay down. He was tired. He needed rest before his heat kicked into the next round.
Izuku obeyed, snuggling close to Katsuki.
The silence lasted a few minutes, until Izuku froze.
“Oh no,” he tried to get up, but Katsuki’s iron grip kept him down. “What about your parents? If they find me here they'll kill me for sure and I’m not old enough to die. Oh god I claimed Kacchan and they said I shouldn’t. Mom said I can’t, that it’s wrong–”
“Nerd,” Katsuki growled. “I don’t give a shit. Rest. It’s already done anyway.” Their parents weren’t going to keep them away from each other forever. They just couldn’t. And they were bonded now. Separating them could lead to a bad drop, worst case–death. And Katsuki was sure their parents didn't want that.
Izuku let out a shaky breath and relaxed. “If Kacchan’s sure…”
“Tch. Of course I’m sure. Never been more sure about anything before,” Katsuki huffed.
Izuku chirped, his happy scent spilling over the few rancid notes he let out earlier. Katsuki sighed, his eyes closed, his mind and body ready to fall asleep. “We do need to get you one of those wearable knots,” Kacchan mumbled, half asleep.
“W-what?”
Katsuki didn’t answer. He just hummed, cuddling his omega. He didn’t care what would happen when his parents inevitably would come by later to bring him dinner. Izuku was his mate. For life. And there’s nothing, or no one, who could stand between them.