A/N: Hello! :D This hit me upside the head and possessed my body to the point I needed to write it out. It originally birthed as a twitter thread under my handle. But, it got way more positive feedback than I was expecting so now I need to fully get this out of my system by just writing it.

This was inspired by Yuri On Ice, Ed Sheeran's "Shape of You" and my super secretive love for the Rocky & Creed boxing movies. I hope you enjoy!

Warnings: Unbeta'd. I am just yeeting this into the universe. Very self-indulgent.

Chapter One - T.K.O

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"The winner is Ground-Zeroooo!" The referee called out, holding up his hand.

Katsuki's chest heaved heavily as the referee held up his tired fist and the crowd went wild. Fans of all ages, sizes and color cheered him on, chanting his name. People waved around decorative signs that read different things like 'We love you GZ!' or 'Number One Fighter!'.

The burly alpha that he had just knocked out cold on the floor had given him a little bit of a tussle, but it barely lasted, and it made him churn unhappily.

Where was the fucking challenge?

He didn't even register the show girls bringing out the golden belt to him, yet again. All the noise in the background blended together as his coach, Yagi Toshinori, formally walked up behind him and led him out of the ring.

Katsuki didn't even bother smiling as the news reporters took photos of him with the precious prize and tossed various questioned into the air.

"Bakugou! What do you think is the next stage in your career as the undefeated champion for five years in a row?" One particularly annoying extra newsman asked him. "Are you afraid for your upcoming fight with the rising star contender, Lemillion?"

Katsuki snorted in response.

"I would be afraid if anyone actually stood a chance against me."

There was a loud eruption of laughter at his snarky remark.

"Do you think you'll regret saying that?" Another reporter asked, holding the mic close to his face.

A string of shudders went off, indicting flashes from cameras and everyone recording what answer he was about to give.

But he didn't care, no. Not really. Not anymore.

"Naw, I'm not gonna regret saying it."

And when the fight came around in a week's time, he didn't.

He knocked out Lemillion within five minutes.

. . .

Japan Times: Sports News

Ground Zero: The Undefeated Champion!

Yet another amazing season for the crowned alpha, Bakugou Katsuki. He won all of his matches without barely breaking a sweat and the crowd is just loving everything he does!

For the fifth year in a row, Bakugou remains undefeated ever since past reigning champion, Yagi Toshinori, also known as All Might in the ring, introduced him as his trainee…

...Read More

. . .

Katsuki groaned out loud as he clicked his phone shut. More of the same, always the same shit day in and day out without any change of pace.

He won every round against everyone that matched up against him. And he even created new groundbreaking rules about fighting in a weight class up after he nearly went feral, demanding for someone who could at least make him break a sweat.

But nothing.

Always absolutely fucking nothing.

"This is such a waste of my fucking time," the champion growled out as he threw his workout bag on the locker room floor.

"Dude, you need to relax!" Kirishima laughed from beside him. "Some people would be okay with just relaxing at the top, you're getting all the good pay!"

"Yeah. What-fucking-ever," he mumbled out, starting to change into his training gear. "I didn't pursue being a fighter because of the pay, Kiri. I joined so I could knock off some of my access aggression and actually enjoy some consistent challenges in life. Instead, what do I get? Yagi tossing me weak ass steroid-pumped alphas left and right."

"Ah, well, that's not entirely Yagi's fault. Everyone's so into the rules now a days that they're afraid to branch out and really give it a go in the ring. People honestly have forgotten what it really means to dig into your primal instincts and truly fight."

Katsuki clicked his tongue and shrugged because Kirishima wasn't fucking wrong.

Recently MMA fighting in Japan had been getting more people who were into just going through the motions and trying to make it a show. These people just wanted to get in and get paid, something Katsuki never really cared for.

When he was growing up, All Might was the champion and he was a goddamn powerhouse. He showed the world what it really meant to be both a fighter and an alpha back when fighting-centered sports were still a bit more on the instinctive side.

He missed the days when people could let go and truly let their base reactions out, but with the growing restrictions on alpha's and their problematic aggression, many fighters shied away from digging that deep inside of them anymore.

"I wish there was a way I could just fucking find people who actually wanted to fight and not put on a show." Katsuki groaned, leaning against the locker. "Ain't no passion in it anymore and it pisses me off."

"Er, well...there is one way that I've heard recently."

The tall champion quirked a curious eyebrow at the now nervous looking red head.

"What?"

Kirishima shook his head and turned away from him. "Nothing, never mind. Forget I said anything!"

If this were any other day, Katsuki would've took the hint and said 'whatever'. But on this particular day, he was feeling rather fed up with his career and now his interest was peaked.

"Naw, spit it out, dipshit," he hissed lifting himself off the metallic surface and getting into the other fighter's space.

Kirishima looked at him wearily before quickly shuffling around to make sure no one else was in the empty locker room but them. When it all checked out, a goofy looking grin broke out over his face as he leaned in to whisper his next words carefully.

"I heard from Denki about this super secret underground fighting ring in Tokyo—BUT it's super locked down, yo."

"The fuck, are you are serious?" Katsuki reared his head back to stare at his friend like he was a total dumbass. "People actually do that shit you see in movies in real life?"

"Yeah! It's super cool, bro!" Kirishima continued and Katsuki felt the hairs on his arms start to stand up. "Only catch is that you can only get in through connections or if you drop hella cash since it's sorta illegal. On top of that, you gotta drop even more cash if you even want to try to participate in the competition."

Several warning flags went up in his head. This was a terrible ass idea—but the notion only egged him on more.

There was something about the potential danger that spoke to something deep and primal inside of him. He felt his alpha growl at the prospect.

"What's the prize?" He pressed, trying to contain the growing excitement.

"Winner gets to take home twenty-percent of the profit from the week at the end."

Katsuki gave a mischievous smirk to his best friend who gave him one right back.

"Wanna get into some fucking trouble like old times, shitty hair?"

"Only if your hot head ass is leading the way."

"Fuck it," he chuckled. "Where the hell do we sign up?"

. . .

Katsuki should've fucking known when Kirishima said that this shit was 'underground' that it would be located in the sketchiest part of Tokyo.

They walked down some strange alley that was on the outskirts of town, dressed in dark colored hoodies drawn all the way up. Both sported black disease masks to disguise their faces.

The alley gave way to an even more sketchy looking backdoor of what he presumed to be an abandoned building, but low and behold, there was some tough looking alphas guarding the door.

Both men looked them up and down with stale faces as they approached.

"You two got the Password?" The largest one asked.

Kirishima grinned from underneath his mask and spoke the magic word with a level of happiness like he was going to Disney World. "Carnage!"

The two men looked at each other and then side stepped to open the steel door that led down deep into what truly felt like the underworld.

The staircase glowed brightly from the purple and red lights coming from inside and the mixed scents of various musky alphas and betas hit him in the face like an upper cut. The loud bass music that was playing shook his bones and Katsuki grinned like a goddamn maniac when he felt his own wild alpha start to pace around, absolutely fucking ecstatic.

Hell yes.

They walked down the dark stairway and immediately they were greeted by some gruff looking betas. Their scents were soft like dusk, not overpowering like the other alphas crowded in the space whose smells could be compared to the hot rising run.

The men took their names, cash and counted every single piece of yen the pros gave with cold calculating eyes.

While this was happening, Kirishima and Katsuki observed the ruthless fight between two betas that was taking place in the middle of the concrete warehouse. It nearly shocked them because these motherfuckers looked absolutely vicious.

The blond had a hard hunch that this would be mainly betas and some alphas since the professional leagues were mainly dominated by alphas that were considered 'top of the line' or what in ancient times called 'pack-leaders'.

But goddamn. These men looked like they worked out every day then plus some. Deep cuts, scrapes and bruises were littered all over their skin and it just screamed animalistic at its core.

Katsuki would be lying if he said he wasn't sort of excited to get inside that caged ring.

Both set of red eyes looked at the impossibly dense crowd that was gathered around the fight, shouting curses and shaking all six sides of the ring. People were stationed all over. Majority were watching the fights, but some were off to the side changing clothes and shadow boxing. Katsuki presumed that these people were going up next to fight.

"Alright, it seems like it's all here." The cashier spoke, putting the yen into his pocket with a sarcastic smile. "Have fun inside, Ground Zero. You too, Red Riot. Our lips are sealed."

"Oh man, oh man! This is gonna be great!" Kirishima exclaimed rubbing his hands together as they walked fully inside, the body heat and scents from the thick crowd fully immersing them.

"Hell yeah it is," Katsuki replied with a hungry smirk.

They started to gear up, with Katsuki putting on his sleeveless black skull tank and black and orange shorts. Kirishima on the other hand just decided to go shirtless with his classic red boxing shorts.

As Katsuki tied up his signature orange and green gym shoes, he looked up at the chalkboard that had all the lineup lines on it.

The blond alpha tilted his head slightly when his bracket was "G.Z vs A.S" and there wasn't any more information given.

He briefly wondered if he should ask around for who "A.S" is or even what the hell it stood for, but he didn't care too much. He had a hunch that they were just gonna pair him up with another alpha based on his stats.

Or at least that's what he hoped for. He was fucking itching to actually get a chance to show his real skills.

When he looked back on this, Katsuki would regret not asking around sooner.

. . .

"Now, ladies and gentlemen the match up of the night!" The loud voice of the commentator echoed into a mic. "I present to you, the reigning champion of the MMA leagues: Ground Zeroooo!"

The reaction from the crowd was downright ravenous. The sound of this pack of people was louder than any noise the audience in the professional stands had ever made. People cheered, boo'd, and some even threw flat out vulgar curses at him.

And Katsuki fucking loved it.

He gave a close to feral grin as he soaked in the wild atmosphere, allowing himself to get swept away by the energy and adrenaline pumping through his veins. The bass music got louder and Katsuki flashed a handsome grin to his best friend who was cheering just as loud as everyone else.

"And now, give a warm welcome back for his opponent! Our lovely champion took some time off but is now back full force! The one, the only, the crowd favorite: Alpha Slayeeer!"

"Alpha Slayer?" Katsuki parroted, confused.

What the hell was that supposed to mean? He stilled confused while looking around at all the wolfish smiles that looked thirstier than what he saw in the previous matchups.

Then, as the crowd's intensity spiked and the ring shook even more, in walked the sexiest son of a bitch Katsuki had ever laid eyes on. His breathing stopped in that second the moment bright green eyes locked with his.

The male was built like no one he's ever seen, thighs stacked to the fucking heavens. They were strong, muscular and thick enough to crush several men's skulls at once. Probably could even start a few wars while he was at it. Goddamn "Hips of Troy" is what this man should've been named.

Viridian colored eyes raked over the crowd as the mystery man waved to all his underground fan, who all looked downright ecstatic to see him. His dark green curls bounced in an impossibly gorgeous manner and the freckles on his face matched the shy dimples that showed on either side of his way too fucking innocent looking face.

The man's chiseled v-cut was on full display underneath a very short green crop top hoodie and his ass was fully outlined in the world's tightest pair of spanx shorts he's ever seen.

Then that's when he smelled it.

It was thick, sweet and mimicking a mixture of honey plus cinnamon. The natural perfume of the man in front of him stood out amongst all the other pungent scents of alphas and betas in the packed underground.

This man was a goddamn omega.

Katsuki felt his nostrils flare in absolute irritation.

"Is this some kind of goddamn joke?" He called out to the referee on the other side of the ring. "I ain't into hitting omegas. Do you know who I am? I came here to find a fucking challenge."

The crowd started booing but Katsuki just rolled his eyes. Why the fuck did was everyone so goddamn worked up to see him fight an omega? At the very minimum he was expecting to get one of those vicious looking betas he witnessed fighting earlier.

"Aw, c'mon, Kacchan. I promise I'll go easy on you," the omega suddenly taunted him, walking up to meet the pro in the middle of the ring. The crowd erupted in an earthquake of laughter.

"Who the fuck are you calling Kacchan, short stack?" He bristled, not liking the coy tone that was taken with him.

"You, Bakugou Katsuki." The omega smirked and began circling him like he was prey. "Top of the league at the moment, impressive stamina stats along with incredible knockout rates. But no one can seem to knock you down a peg."

"You fucking stalk me or something?"

"No, just a really big fan of yours, Kacchan."

Katsuki growled as the man stopped in front of him. He glared heated daggers into the smaller male, who just flashed a sickly-sweet smile up at him.

"Whatever. Let's just make this quick, Deku," he jabbed and everyone in the audience booed.

"Alrighty, just remember what you asked for."

The omega grinned at him like this wasn't about to be a fight, bouncing lightly in his red sneakers.

As they took their stances waiting for the bell, Katsuki would be lying if he said he wasn't half checking the man out. He was a goddamn knockout looks wise.

There was a thick air of silence as their eyes met and the pro fighter could feel his alpha stir looking at the competitive omega in front of him. He could feel his pheromones get stronger as he watched the pupils of the greenette in front of him dilate.

There was a magnetic pull that Katsuki had never felt before as they assessed each other.

"And begin!"

The bell dinged and before Katsuki could blink, he was bum rushed by a blur of green.

He tried to put his hands up, but the omega was quicker.

The athletic man jumped to a height he didn't think was possible and strong thighs wrapped around his neck, blinding his vision. Katsuki yelped as he was slammed forward onto the mat without a moment's hesitation and the man rolled on top of him to pin his arms with his knees.

The second the pro finally opened his eyes, he was met with fiercely burning green ones and a fist collided with his face ruthlessly.

Everything went black.

. . .

Cold water splashed onto his body and a hand tried to vigorously slap him awake.

The first thing Katsuki heard was Kirishima's distinctive annoying ass laugh.

"What the fuck just happened?" the blond rasped out, groggy as shit. His head was painfully pounding, and he could feel dried blood caked underneath his nose.

Kirishima's laughing got louder.

"Dude! You got knocked out!" The redhead doubled over, clutching his stomach. "All that shit you talked, and you actually got knocked the fuck out!"

More laughter and snickers joined in from the betas and alphas surrounding him. Slowly, the reality of what just happened dawned on him.

He got T.K.O'd in front of all these goddamn extras in barely a fucking minute.

A low chuckle erupted from his chest.

"Fuckin' finally," he grinned out of relief, shocking everyone. His smug looking red eyes glanced up at the rough looking beta who was currently squatted beside him. He gave a hungry grin through his bloodied nose. "Where is he?"

All the people nearby paused their laughter, baffled by his reaction.

. . .

Katsuki searched the whole goddamn warehouse for the omega but couldn't find him.

Turns out he was knocked out for the remainder of the competition and 'Alpha Slayer' had won this week's earnings, leaving out through the back door last anyone saw him.

The blond alpha asked around to a couple more people until he finally got a lead of sorts.

"Izuku has a chip on his shoulder," a shady looking man told him. "I'd be careful how you speak to that one. Ain't too fond of cocky ass alphas." A pointed look was thrown his way and Katsuki just waved the man off.

He almost thanked the man because at least now he had a name: Izuku.

Katsuki ran out the back door, frantically searching and he walked a whole block.

He didn't know what was driving him to do this. Part of him felt like it was his alpha telling him to follow the absolutely fucking badass omega, but...there was something else there that he couldn't explain.

Just when he was about to give up hope, the cinnamon like honey smell washed over him again.

He snapped his head in the direction of an old worn-down bus station where the greenette was sitting, hunched over on his phone as he sat in the late summer air.

Green eyes widened as the tall alpha approached him, surprisingly almost out of breath. Immediately his body posture shifted to defensive.

"What are you doing here?" The man now named 'Izuku' scrutinized him. "If you're here just to spew more sexism I don't want to hear it—"

"—Let me fucking coach you," Katsuki rasped out quickly, shocking them both.

"E-Excuse me?" The freckled man leaned back clutching his phone tighter in his hand.

Katsuki rolled his eyes as he got closer to the sweet-smelling man.

Why had he said that? He had no real clue. He was just following this stupid ass feeling in his chest that was more powerful than anything he's ever felt. The pull only got stronger the longer he looked into those hypnotizing green eyes and he decided that this couldn't be the last time they ever spoke.

Not after what just happened.

"I hate repeatin' myself but fuck it. Let me coach you." Katsuki pushed, and he could sense Izuku's defensive wall falter ever so slightly. So, he kept going. "Do you know how many damn idiots couldn't even pin me down in the last five years? And then you just come in like a fucking avalanche and actually knock me out in less than five seconds?"

He cautiously stepped closer to the sitting greenette, trying to present himself as non-threatening.

Katsuki watched as the omega looked him up and down, assessing him fully. When those green eyes locked with his again, he could've sworn he saw something close to want flicker inside of them.

"Okay," the greenette replied, shocking them both yet again.

There was a strange gravity in the air that Katsuki couldn't exactly explain, but he wasn't about to question it right now. He was still stunned that he had gotten knocked out by a total knockout in the first goddamn place.

"What's your name?" He asked carefully, eyes never leaving the other's.

"Izuku," the light voice softly replied, holding out a hand. "Midoriya Izuku."

A/N: Please let me know what you think! This is my first shot at A/B/O and I hope it came off well 😁! I love feedback & comments.

This story is gonna be relatively shorter and fluffier compared to my past stories, which I'm happy about. It's gonna be 3 parts + epilogue and super fluffy to balance out writing the monster fic that is Incinerate.

Thanks so much for reading!