Chapter Text
Deku’s favourite times of the week were undoubtedly the times he spent with Kacchan, whether that be patrolling the streets of Musutafu or sparring with the hot-headed alpha during one of their Hero Training lessons. They had long passed their days of animosity and now were arguably the closest two in Class 1-A.
Even though the Prime had a tendency to go overboard sometimes, he admired how the Alpha was the only one not to go easy on him when fighting because he happened to belong to the omega subgender; as the only one in the class he was prone to being coddled by his alpha and beta classmates. They didn't do it on purpose but their instincts made them worried by the thought of hurting him unintentionally. He didn’t truly mind as they promised that they would attempt to stop.
They had just started their third year at UA and they still wouldn't go all out.
Correction, they wouldn't go all out on him. The greenette was proud of how much his classmates had grown, both as hero hopefuls and as citizens in their still-prejudiced society. In the beginning of their first year there had been a large amount of controversy over whether or not Izuku should be allowed to stay in the hero course due to his status as a rare male omega, the only one to have entered UA in the school’s history, yet alone in the hero course. They were rare, making up only 1% of the already low 5% of people that made up the Omega gender. They were especially fertile, almost never having less than 2 pups per litter which made them valuable to repopulating society. Hero work could potentially hurt their wombs and incapacitate them from having pups of thy were too injured.
Deku had quickly disputed the worries of him getting hurt badly when he won with his classmate, Ochaco, against two especially strong alphas in their first challenge, even if he did pass out into the arms of his self-confessed rival at the end. Since then, he had worked hard to gain the respect of his peers and to his avail, it worked.
By now he was ranked only second to Kacchan and was still aiming to change that by the end of their year. Even with all of his efforts, he still had a feeling that a few of his classmates were holding back. Namely, the alphas.
Deku dodged a considerably weak punch from Kirishima, retaliating instantly with a 10% powered kick into the other teen’s hardened side. The alpha slid backwards a few metres before regaining his balance, coughing slightly, sharp teeth on show with the grin spreading onto lightly chapped lips. Instead of attacking again, the red-head ran around a pile of rubble that had stacked up from what used to be a building. Confused, the omega leapt into the air. As he was about to engage in an overhead attack, a large body crashed into his own from behind, causing a dull throbbing pain to bloom from his mid back and sending him flying into the rubble pile face first.
He groaned in pain, turning his head to see Katsuki heading towards him, his signature feral grin looming closer as nitroglycerin powered explosions propelled the Prime closer to the omega. Rolling out of the way at the last moment, Izuku hopped around the corner to where Kirishima was about to turn to the next face of the building. Quickly and silently bouncing off of walls towards the Sturdy Hero, Izuku swiftly immobilised his friend, determined to not lose and at least draw with Kacchan. He had come to the conclusion that Tsuyu had been captured by the blonde and knew that he was unlikely to win in a 2 v 1 fight and needed to bring down the opponents number.
Kirishima facing the other way just made it easier for Izuku to bring him down.
Once he was sure that Eijirou wasn't going to be able to move, he lifted him up and quickly brought him over to the “out” zone. Ignoring his friend’s cries of “Not fair!”, Izuku ran back to the building but found Katsuki nowhere to be seen. Wary and still reeling from the harsh kick that he received, the green haired boy crept forward slowly, aiming to scent the air and find the alpha that way. Although his neck glands were covered because of a rule that the school had, Izuku knew that the blonde hated wearing scent blockers on his wrists and would have a better chance finding him by looking for the albeit more subtle scent coming from his wrists.
Creeping forward until he was close to the direction he was sure that the alpha had ambushed him from previously, the omega wondered why Kacchan had decided to hide from him. Stepping over a fallen sign, the young hero’s nose caught onto the nostalgic scent of his childhood friend and his head whipped into the direction that the burning sugar and cinnamon had come from, he noticed an alley directly to his left. Heading into the dark space, he realised that the scent was slowly clearing. A smirk bloomed onto his face at the thought that he would finally reach the end of this gruelling challenge.
Aizawa’s voice echoed throughout Ground Beta, alerting the boys that there was 10 minutes left out of their 30 minute time-limit. The green haired boy sped up into a slight jog, searching for the blonde so they could finish up the assignment and head to their study session in Katsuki’s room. Their classmates thought it was weird that they allowed each other into their rooms whenever the other liked but the pair didn't find anything wrong with it. After they had fought at this very location, their once strained relationship began to slowly improve, and the two became better friends than they had been in a long time.
However, at this moment in time Izuku was really not happy with his alpha friend. Infact, he really wanted to hurt him but he didn’t know why. The familiar smell of burning nitroglycerin swirled into his nose, causing the omega to whip his head around and come face to face with his current object of ire. Katsuki’s features were twisted in a half-smile-half-snarl, baring his long and sharp canines to the younger boy. Izuku growled, unimpressed and annoyed with the alpha at this current point in time. He jumped, missing the blast narrowly and replied with a Full-Cowl kick to the other’s chest.
The blonde Bakugou laughed at the enraged look on the omega’s face.
“Why’re you so pissed off? Still having cramps from your heat?” teased the alpha, grabbing onto the omega’s ankle and swinging him over his head, releasing him so that he flung towards the entrance of the wide alleyway they were in.
“Yes, infact, I am still having cramps and I’d appreciate it if you would stop stalling here so we can go study and then I can go curl up in my nest with a hot water bottle and call it a fucking day! ” growled the omega, not really knowing why he was so angry all of a sudden but really not having the patience to deal with Katsuki’s bullshit at the moment.
“If you say so”, grinned Katsuki, releasing two simultaneous blasts; one was aimed at Izuku and the other was aimed at the wall to the right of the boy.
Using Float to keep him in the air, Izuku deflected most of the cement pieces falling towards him but Katsuki was too fast. An explosion blasted him forwards causing him to hit his stomach on a corner where the cement had been blasted away. Leaning forward as to cover his womb, Izuku scraped his face on the corner of the building as he fell.
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Izuku’s scent spoiling into rotting pine and too sweet vanilla hurt Katsuki’s Alpha but the pained, pitiful whine that escaped hi- the omega’s mouth broke his heart. Body moving on its own, the blond used his explosions to propel him forward so that he could catch the smaller boy before he fell and hit the ground. Small whimpers left the boy’s mouth, his muscular arms wrapped around his abdomen.
“K-Kacchan, it fucking hurts”, more cries of pain were ripped through the omega’s throat, accompanied by soft snarls of contempt “I told you that I was s-still having cramps, my stomach hurts and you blasted fucking rubble into me!”
“Fuck, Deku I’m sorry, I didn’t mean to”, crooned the Prime, using his wrist glands to scent the omega in his arms and mask his soured scent. Their classmates appeared out of what seemed to be thin air.
“That wasn’t very manly, bro!”
“What did you do to Midoriya? Is he ok?”
“Give him to me, I always knew you were too rough with him!”
The last comment came from Round-Face, her cheeks pinker than normal with anger. She marched over, attempting to pull the onega that she had been trying to court away from the other alpha but the green haired boy refused, whining louder and holding onto the vest of the alpha’s hero costume.
“I think it would be best if we allowed Bakugou to take Midoriya to Recovery-Girl”, drawled Aizawa, but even he seemed worried at the fact that Izuku’s scent had not changed back to its usual sweet vanilla and pine and he was still whimpering while clutching his stomach.
“No Recovery”,Mumbled Izuku, “Take me to my dorm”.
“You heard him, take him to his room. Midoriya’s team wins, Teams A and C are next.” Shouted the Underground Hero. Complying yet slightly pissed at losing, Katsuki held the smaller male bridal style and headed towards Heights Alliance.
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As the two walked into the building, Katsuki instantly took the omega to the showers. Once inside, the alpha placed the smaller boy into a cubicle, stepping outside and waiting for the boy to pass the dirty hero suit. He had never truly noticed it but Izuku had only grown about an inch in height since their first year, most likely due to the fact that he was an omega. The younger male had, however, grown in other places. He now had wider hips and and ass that everyone in their class wanted a piece of. His waist had seemingly gotten smaller, giving him a more feminine figure. Even so, the small frame was stacked with muscle.
(Everywhere other than his face. He still sported plump rosy cheeks that refused to leave.)
In his specific case, Katsuki, due to his Alpha genes, had grown a full 8 inches, bringing him to about 6’4. He now easily towered over most of their class, including half’n’half. The only downside was that the cubicle walls and the shower itself were quite short, it was a wonder that Shouji hadn’t talked about it before being the (now second) tallest guy in their class. Stripping down until naked, Katsuki threw his clothes onto the bench where he had placed Deku’s. He then turned on the shower, revelling in the cool water that sprayed over his sweaty body.
Peeling off his scent blockers, the blonde allowed the heavier scent that originated from his neck glands to spread throughout the showers. He heard Deku scoff softly, but soon smelt, tasted the soft vanilla of Deku. It taunted, teased and smelled largely better than it did back at Ground Beta, even if it still had a sour tinge to it.
Katsuki quickly scrubbed the dirt off of his back, rinsing the suds off under the running water.
“Kacchan?”
He grunted in reply.
“You forgot the towels. I’ll go to your room and get some.”
That statement somehow forced words from Katsuki. Eyes widening as he realised what that meant, he turned around. shutting off the water flow.
“You’re butt naked Deku, get back here!” Demanded the alpha, opening the door of his cubicle and walking out.
“There’s no one else here, we still have about another hour before the others come back.” The omega turned his head, smirking. “Or maybe you’re jealous?” The greenette smirked in the Prime’s direction before walking out of the shower room.
Chasing after him, Katsuki walked outside too, noticing that the omega had just gone through his door.
Oh yeah. There are showers on every floor and they were currently on his.
He should be angry that someone walked in without his permission, even Kirishima knew that he would receive a blast to the face if he tried it, but for some reason his Alpha refused to acknowledge the nerd as a potential threat whenever he decided to barge in uninvited, probably because he had known the other for so long.
Following the omega in after a few minutes to make sure that he was at least semi decent, the Prime noticed that his room smelt significantly less like him and more like the omega lying on his bed. In his clothes. In a makeshift nest. How had this all happened in five minutes? He stared at the greenette with a disbelieving smirk before choosing to walk inside. Instantly, the younger hero’s eyes flickered down before a blush spread across speckled cheeks. The older say the way Izuku’s throat bulged when he swallowed and a laugh bubbled up in his throat at the sight. He chuckled, grabbing a pair of boxers and sweatpants from his drawer.
Once he put them on along with a signature black tank top, he noticed that his Omega friend was now standing behind him, pulling on his shirt and leading him towards the nest made of a few blankets and some of the Alpha’s shirts. Once the smaller man had successfully led his friend to the bed, Deku’s painful whining dissolved into soft mewls. The Omega suddenly shrugged off Katsuki’s hands and pushed Katsuki into his nest before climbing on top of him, purring contentedly.
“I won this time,” Hummed the shorter, lying on top of his chest and pressing his cheek into the natural heat of the alpha. “We agreed that if I win, I get free rein over your room for a week
“So was all of that back there fake? Making me feel bad for nothing? I thought I seriously hurt you.” The blonde scoffed, placing his large hands on the younger’s hips and pushing him away lightly. Wincing slightly, Deku lifted the way-too-large t-shirt up, exposing a large, purpling bruise that extended from just below his armpit and spread all the way down to below the waistband of the boxers.
Eyes widening, the older boy sat up properly, lightly running his fingers over the bruised ribs.
“Deku, what the fuck?” Growled the older boy, lifting the younger up and onto the floor. He wondered how he hadn’t seen it when the omega came out of the shower but remembered that the boy was facing away from him at that time. The smaller of the two winced and the shirt fell back down. It reached to just above knee height so that even if Deku was to move around or lift his arms you wouldn’t be able to suspect anything.
“We’re going to Recovery Girl, now.” Katsuki rarely ever used commands on Izuku, only using them when he felt that the idiot wouldn’t listen to reason. The greenette started walking towards the door with an annoyed pout on his face. He was completely unable to disobey the blonde’s orders as compared to the ones of his other friends but he didn’t know why. The blond followed soon after with an exasperated look, grabbing the greenette’s wrist and dragging him towards the door
As soon as they reached Recovery Girl’s office and had seen that she was in fact, inside, Katsuki stormed in. You could argue that he was irrationally angry, especially as a bruise was definitely not the worst injury that the omega had managed to obtain but in actual fact, he was tired of his friend keeping quiet about being injured just because someone else might potentially need help more.
The elderly woman looked up at the two boys clad only in sweatpants, a vest, slide-on slippers and one very oversized shirt. Using her syringe-shaped cane, the beta lifted the base of the large garment; she had come to know that the omega would often hide injuries as to not worry others. Tutting at the sight of deep purple spread over once mainly clear (if you were to count the scar tissue) skin, she brought out a small pack of gummies and threw them in the blond’s direction. She then whacked the green haired omega in the thigh, causing a whine to leave pouted lips. The alpha nodded with approval and proceeded to tug the omega back out of the door and towards the dorms.
As soon as they were back in Katsuki’s room, the short boy stomped over to his current nest and curled into it, facing the wall away from the other. Not one to be deterred, the alpha sat onto the bed. Reaching over to ruffle green curls, he received a swat to the hand.
“Don’t touch my nest or me when I’m in it”, huffed the omega, refusing to properly acknowledge the boy on the bed.
“You’re in my room Deku, I can throw you out whenever I like”, chuckled the blonde.
“I have free rein for this week”, replied the angered teen, “Go fuck off somewhere else”.
Rolling his eyes, the blonde stood up and headed towards the door. “Just because you have free rein over my room right now doesn’t mean that you can boss me about. I didn’t agree to relinquish my rights over this place. But hey, do you”.
At the sound of the door opening, Deku’s head whipped around to look in that direction. In an instant he was whining and pulling the tall alpha back into his room, much to the humour of the other teen.
“Ok, ok. I’m sorry! Stay here, please?” chirped the omega sweetly. The multiple mood swings were a sign that although this was likely the last day, the omega’s heat was surely not over. Something for Katsuki to tease him about when he wasn’t feeling as sensitive. “My nest is amazing, isn’t it? Of course i’m going to be a bit protective of it!”
Not wanting to admit that seeing the nest made out of his belongings made him want to kiss the daylights out of the omega, he downplayed his reaction. Maybe not the smartest thing to do.
“It’s basic as fuck. Messy too”, teased the alpha, forgetting to take the greenette’s out-of-whack hormones into consideration.
The change in scent was instant. The room went from smelling like freshly rained-on pine trees and cold vanilla ice-cream to rotting wood and mouldy cupcakes, indicating that the omega was upset. The explosive blonde stood up, moving so that he was crouching beside the small boy’s frame. The young boy’s whole body was racked with sobs and the older could see tears falling down his round cheeks. Quickly lifting the teen up so that he was sitting with his legs hanging off of the edge, the alpha lifted his neck and rubbed it against Izuku’s, effectively scenting him.
“Izuku, I’m sorry alright?! Your nest is beautiful, it looks great. Please stop crying, I’ll extend the amount of time you can have in my room up to two weeks!” The alpha was rambling in an attempt to stop the tears from falling down. The entire day had been eventful and a grilling for upsetting the only omega in UA history was not something that Katsuki wanted to deal with.
A smile rose onto the omega’s pink lips, freckled cheeks dimpling from how bright it was.
“You think my nest is beautiful? Thank you Kacchan!” The pleasant scent returned once more, causing the blonde to huff in relief. “Do you think you could get my books from my room so that we can study? Pretty please?” The omega batted glassy jade eyes at him, flushed cheeks joining to add a downright sinful look onto the other boy’s face.
Turning his face as to not show his furious blush, Katsuki stood up, quickly exiting the room and sprinting down the flights of stairs to Midoriya’s room. Once on the second floor, he quickly barged into the room.
Big mistake.
The innocent teen’s heat scent covered every inch of the All Might shrine that was Izuku’s room, causing the alpha to scent the air deeply. The rooms smelt like burning wood and marshmallows, a perfect outdoorsy scent that just screamed Izuku. In an attempt to not get distracted he ran forwards blindly where he thought was Deku’s study desk, instead falling into the omega’s nest face first and fuckkk if suffocating in that pile wasn’t a great way to die. It was covered in the nectar sweet smell of slick yet had none of the crusty residue that the substance left behind once dried.
It was soft, just like the omega. Opening his eyes and pulling his head off of the nest, he noticed that his favourite skull shirt was right at the top, saturated completely in the sweet scent. Crimson orbs widening, he picked it up before turning around to grab the books and head back up to his room, slamming the door behind him in an attempt to remove the scent of heat from his nostrils. As the hot-headed alpha stomped up the stairs he couldn’t help but wonder why Izuku had taken the shirt without asking. Katsuki didn’t mind scenting items for him so he found it a little odd that the omega would take it.
Reaching his dorm, he opened the door to see the nerd scenting his bed. Exasperated, he pulled back the boy by the middle. That caused a laugh to escape those luscious pink lips as scarred hands wrapped around thick wrists.
“Shitty nerd, why’re you stealing my shirts, hah?” questioned the blonde, digging his fingers into the shorter boy’s waist as he knew it would get a reaction.
Chuckles from Deku proved his point, although the boy squirmed slightly in pain. “I just felt like it”, giggled the omega, curling into a ball while still in the alpha’s arms.
“Fucking Deku”, growled Katsuki playfully, throwing the greenette on his bed and into his nest. A slight hiss of pain escaped the younger boy, along with a few chuckles. Placing the jostled garments back into order, the omega again pulled the alpha down onto him. He grabbed a warm hand and placed it onto his stomach, purring at the heat that spread throughout his body.
“Way better than a water bottle”, chirped the blissed-out omega.
“What happened to studying, dumbass?” huffed Katsuki. Contrary to his words, he began rubbing soft circles onto the boy’s body, rolling them over so that Izuku was now lying on top of him.
“Later. Let’s sleep now”, crooned the shorter male, laying a freckled cheek onto the alpha’s chest. In a few minutes he was asleep, leaving Katsuki to massage soft circles into his hips and stomach.
Their relationship was weird in the sense that it sat directly on the borderline of romantic and platonic but it’s suited them perfectly. They wouldn’t change it for the world.