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A roar echoed through the air, loud enough to vibrate the glass of the dorms. Katsuki, who had been sitting peacefully in his room doing homework, was up in a flash along with the rest of class 1-A. "What was that?" Kaminari asked as he joined the cacophony of students in the main area.
"If we knew, why would we be here?" Katsuki scoffed before another roar broke out, causing everyone to cover their ears. Of all the students there, something interesting happened. Kaminari, Jiro, Kirishima, Tokoyami, and Uraraka all fell to their knees as if the noise forced them to yield. As if an Alpha was forcing them to yield. Without stopping to check if his classmates were alright, Katsuki was flying out the door and toward the main building. All along the sidewalk, there were omegas on the ground, cowering away from the noise that seemed to have little effect on betas and no effect on alphas. Then he saw the source of the noise.
The teachers were surrounding a massive animal with light and dark green fur. It almost looked like a tiger if that tiger had taken a swim through green paint. Class 1-A wasn't the only group of kids running to see what was happening either. It seemed that the abnormal roar could be heard at every corner of the school. "Is that a tiger?" one kid not far away from him asked, some nobody from class B.
"Is it a quirk?"
"It has to be!"
The chaos was rising, and the longer the teachers struggled to rein in the rampaging tiger, the more the students became anxious. Then the inevitable came upon them. Mr. Aizawa stepped into the fray, and almost instantly, it was over. However, it did not end as one would expect. No, they found it was not a quirk that Aizawa could erase. No, instead, the moment that Aizawa walked onto the grounds, the beast stopped attacking and ran straight for him. Aizawa used his capture scarf to tie the beast down, but as quickly as he had tied it down, the beast warped its form and took on that of someone familiar. "Deku?!" Katsuki yelled as Izuku freed himself and came barrelling toward Aizawa. Katsuki was about to act when he realized that Izuku wasn't attacking but rather hugging Aizawa as if his life depended on it.
Katsuki, now pissed, stormed toward the duo. The closer he got, the more he realized that Deku didn't look like he normally did. That and he was acting animalistic. The first detail that Katsuki noticed was different was the tiger ears that had replaced his human ones; then there was the tail and the claws. While he was no longer a tiger, he still had those tiger features. "What the fuck did you do?" Katsuki demanded, tugging on the boy's shoulder. Too bad that Aizawa was there to put a hand on his head and remind him who was the boss. It was also then that Katsuki stopped thinking just enough to catch the strong scent of pine and citrus. It was a scent far stronger than Izuku's normal mint and citrus.
"Bakugou, that's enough. Go back to the dorms. I'll handle this." Katsuki couldn't refuse. As much as he wanted answers, he had no choice but to trust in his teacher and go back to his dorm. The walk back was grim. It was filled with jelly-limbed omegas trying their best to stop shaking. The real question on Katsuki’s mind was how in the world could a weak omega like Deku be able to bring all the other omegas to their knees. It made no sense! He was weak!
When Katsuki got to the dorms once again, he was met with the same sorry sight. Kaminari, Kirishima, and Jiro were sitting on the couch, each wrapped in a blanket, and there was no sign of Tokoyami or Uraraka. All the rest of the class was either waiting for news or helping their omega friends. “Bakugou! Did you find out what it was?” Yaoyorozu asked, her tone laced with worry.
“It was fucking Deku,” Katsuki growled out, storming toward the stairs and leaving the rest of the class speechless and confused. Imagine their surprise three hours later when Izuku was brought back to the dorms, and they got a good look at what a quirk accident had done to their friend.
“Midoriya is acting more like a cat than a human!” Iida exclaimed. Katsuki, not wanting to really be part of this, stood at the stairs, watching as Aizawa brought Izuku into the dorms wearing a thick collar and toting a leash.
“There is one more thing that’s changed,” Aizawa responded before Tsuyu piped up.
“Does it have to do with his new scent?” she questioned, tilting her head a bit.
“Yes. After some deliberation, we came to the conclusion that whatever happened caused him to turn into an Omega Prime.” Aizawa explained. There was a chorus of murmurs and gasps. Even Katsuki was caught off guard. Primes were legends. As the population evolved, primes became a thing of the distant past.
“What the fuck does that mean? He’s more animal than human?” Katsuki almost growled as he moved closer to Aizawa, and the group gathered around Izuku.
“That’s exactly what that means.” Aizawa answered, “Not sure if he can talk, haven’t gotten a word out of him since he got on campus.” he continued as Katsuki made his way to the front of the group. As soon as he did, Izuku did the most unimaginable thing in his mind.
“Kacchan!” Izuku purred, throwing his arms around the blonde and startling everyone in the room.
While Katsuki was getting nuzzled by Izuku, Aizawa simply hummed in thought. “I guess he can talk.”
“Great, someone get him off me!” Katsuki yelled, unwilling to admit how soft Izuku’s furry ears were against his neck. The more important part was that Izuku was scenting him! He was starting to smell like pine!
The moment someone moved to do just that, Izuku let out a sweat-inducing growl that immediately had all the other omegas on edge. “Looks like Midoriya is your problem.” Aizawa muttered, “I need you kids to keep an eye on him while the teachers try to find the culprit.” with that, the man turned around and left, leaving Izuku still in Katsuki’s arms, nuzzling into his neck and purring loudly.
“Sorry, Bakubro, I think Midoriya decided who he wants to spend time with,” Kirishima muttered before Katuski grabbed Izuku by his shirt collar.
“Like hell he did! Get the fuck off me, Deku!”
“Mine!”
“No!”
“Yes!”
“Get away from me!” After a decent fight on Bakugou’s behalf, he finally ceded as he realized that Izuku was not going to give up. Instead, he headed up the stairs, Izuku still practically attached to him and to his room to finish what he had been doing before Aizawa brought this wreck into the dorms. “Leave it to Deku to get into a quirk accident…” he grumbled as he practically pushed Izuku onto his bed so he could comfortably sit at his desk. “Stay,” Katsuki demanded, and Izuku obeyed. For hours, Izuku obeyed until finally, Katsuki got up for a light snack before he went to bed.
As Katsuki thought, when he left the room, Izuku was right on his tail, figuratively as Izuku was the only one with an actual tail. He made his way down the stairs and toward the kitchen, passing by a group of his classmates as he went. He spotted a few eyes on him as he passed, though only the omegas had paid attention to his presence- or should he say Izuku’s presence.
Katsuki mostly ignored them as he walked to get his snack, that was until there was a scream. Now, he usually wouldn’t have put too much thought into what had happened, they were safe in the dorms after all, but when Izuku responded by shifting back into a tiger, it became his problem too. Izuku roared as he bounded out of the kitchen and straight toward the other students of 1-A. “Deku!” Katsuki called as he followed close after. By the time he made it to the common area where everyone was, Izuku was already in pursuit of them– or rather, one of them. Izuku was after Mineta. “What the fuck happened?” Katsuki yelled as he put himself between Izuku and Mineta, just as the tiger was about to tackle and probably squish the boy.
“Mineta groped Jiro.” Mina stated, holding the girl close and comforting the obviously grossed-out girl. While Katsuki was looking toward Mina and Jiro, Izuku tried to get around him. A single explosion from his right hand pushed him just enough to block the tiger again.
“Deku. No.” at this, the tiger snarled and growled at him. “No,” Katsuki repeated, trying to think of a way to get Izuku to calm down. There was only one way he could come up with it, and he hated it. Despite that, he had no choice. He knelt down, wrapping his arms around the large feline and pressing into his soft fur. He pressed his scent glands to Izuku’s and started scenting him, trying to calm to omega prime down enough to change him back to semi-human form. Out of the corner of his eyes, he could see his classmates gawking at him, but as long as no one got mauled, Katsuki would deal with it.
Soon enough, the massive feline body turned back into that of Izuku, naked as his clothes had torn in the shift. Most turned away immediately. Tokoyami merely tossed his jacket over to Katsuki who took it and covered Izuku’s lower half. As Izuku kept nuzzling into him, Katsuki looked over at Mineta. “Next time, I let Izuku eat you,” he explained as he picked Izuku up bridal style and headed up to the boy’s room.
Getting him dressed was about as easy as getting a child dressed after they had eaten a mountain of sugar. Though, when he finally did, it was past his bedtime, and he was getting a bit grumpy about that. “Bed,” Katsuki stated as Izuku sat on his bed, tail swishing happily behind him. “Stay.” he continued as he tried to leave the room, but when he did, Izuku was quick to stand up and follow him. “Stay-”
“No!”
Time was ticking by as he tried to get Izuku to stay in his own room, and to be honest, he was getting more desperate to go to bed. So, he made a decision that he usually would never have considered. “Fine…” he muttered, taking Izuku by the hand and leading him toward his own room. Yes, he decided that if it meant he could go to bed on time, he would let Izuku sleep in his room. On the floor. Like hell, he would let the boy sleep on the bed with him.
Though, as soon as he got into his bedroom, Izuku bounded past them and onto the bed. Fine. He could deal with this for one day. Izuku could have his bed. He had a spare blanket anyway. With that said, he got ready for bed, laid out a blanket, and stole a pillow from his bed before making himself comfortable on the uncomfortable ground. Katsuki closed his eyes, settling his heartbeat so he could sleep. Then there was a fwump behind him and warmth covering his back. When he sat up to look, the massive tiger Izuku was behind him, curling up around him and laying his head down near Katsuki’s pillow.
For a moment, Katsuki couldn’t register how to react to this. He was tired. He wanted to sleep. Whatever, he would deal with Izuku in the morning.