My Harem System In My Hero Academia

Everyone walked to the changing rooms, splitting off into boys and girls. Momo hurried into the girls' locker room, her heart pounding from the embarrassment. 

She quickly stripped off her U.A. blazer and skirt, revealing her slim, toned body—and her slightly bloated belly. Her fingers brushed over her tummy, feeling the way it sloshed slightly with each movement.

It wasn't fat. Not exactly. It was something she actually wanted to keep there.

The damn plug wasn't helping. She adjusted it discreetly, making sure it was tight and secure in place so no cum leaked. 

Momo couldn't risk anyone finding out what was inside her. But as she pulled her gym uniform over her head, she caught a glimpse of Hagakure—the invisible girl—watching her curiously.

"You okay, Yaoyorozu?" Hagakure asked, concerned by the blushing and sweaty Momo; her voice was soft, almost hesitant.

Momo forced a smile, tugging her shirt down to cover her tummy. "Y-Yeah, I'm fine. Just… feeling a little bloated."

Hagakure giggled. "Don't worry! I totally get it. Honestly, if it weren't for my Quirk, I'd probably have to wear corsets all the time."

Momo laughed nervously, relieved that Hagakure didn't see the plug. But as the other girls chatted and changed around her, Momo couldn't shake the feeling that they were staring at her, judging and whispering.

She pushed the thoughts away... for now, at least.

Meanwhile, the boys' locker room was doing what high school boys do best, stupid shit.

"Dude, check out Bakugo's arms!"

"Bro, Kirishima's got abs to strand cheese with!"

Yami was in the corner of the room, trying not to catch too much attention since his ribs hurt a little from the U.A. entrance exam, thanks to a certain useless bastard... still, Yami was in a good mood today.

But the room fell silent when Yami pulled his shirt over his head.

Yami's body wasn't just muscular—it was freakishly built, like a statue carved from stone. His abs were chiselled, his pecs were solid, and his biceps bulged with veins. 

His skin was smooth and unblemished, like a baby's ass or Momo's tits.

"Holy crap…" Kaminari muttered, his jaw practically on the floor. "You look like a freaking pro hero already."

Even Midoriya, who'd spent months training his body, looked scrawny compared to Yami.

Bakugo scowled, his bad temper flaring up. He hated being overshadowed, especially by someone new. "What the hell are you on, Iwatani?"

Yami didn't even flinch or spare a gaze at Bakugo. Still, he really hated him, even in his first life, so Yami glanced at Bakugo with his usual calm, smug expression. 

"Not my fault if you're feeling insecure, you spoiled brat."

Kirishima chuckled, stepping between them to defuse the tension. "Dude, seriously! What's your secret? What have you been eating?"

Yami smirked. "Protein. And your mom."

Everyone but Bakugo and Iida laughed, even though the pair didn't laugh for different reasons, and even Kirishima had to admit he walked into that one.

Out on the training grounds, Aizawa-sensei stood waiting for everyone. The students gathered nervously, chattering about what they thought they would do.

"We're going to conduct a Quirk Assessment Test," Aizawa announced, his voice as monotone as ever and tired as ever. 

"This will determine your physical capabilities with Quirks. You'll be performing a series of standard fitness tests—but with no limitations on using your Quirk."

The students murmured among themselves. Fitness tests? That didn't sound so bad...

Aizawa's eyes narrowed. "And the student with the lowest score… will be expelled."

...Well, shit.

Momo's heart skipped a beat. Expelled? On the first day? Well, it wasn't so bad since if she got expelled, she could fully become Yami's sex slave and wife and could work to take over her parent's company to gift it to Yami later as a wedding gift and then have a lot of baby making sex, and then she'd spend time with Angela and...

"Momo, please stop being yourself," Yami muttered in her ear as if he had read her thoughts. Momo blushed and stopped thinking about that.

"Sensei, isn't that a bit harsh?" Iida raised his hand and asked, more out of curiosity than solidarity.

"No," Aizawa replied bluntly. "You're here to become heroes. In the real world, failure means death or worse. If you can't handle a little pressure, you don't belong here."

The tension was palpable and could be cut with a knife or touched like an ass as Aizawa pulled out a softball and handed it to Bakugo.

"You're up first. Softball throw. Use your Quirk."

Bakugo grinned, finally in his element. He stepped into the circle, wound up, and exploded his palms as he made a throw that sent the ball flying out of sight.

"Die!" Bakugo yelled as the explosion propelled the ball further than any regular throw should.

Aizawa glanced at the monitor. "705 meters."

The class gasped. "Holy crap! That's insane!" Kaminari exclaimed.

But Yami barely paid attention. He was more busy thinking about what he'd eat for dinner if either Angela or Momo.

When it was Yami's turn, he stepped into the circle slowly with his hands in his pockets; once he was in the centre, he threw Momo a kiss before Aizawa handed him a softball. 

Yami gripped the softball tightly, his golden eyes narrowing as he thought of a technique he'd seen in Baki the Grappler.

It had been years, but some things stuck with him from the anime and manga he used to binge while gooning. 

One of them was a move in which a fighter imagined his arm having extra joints, like a whip, to create a super-fast punch to defeat a giant pickle.

Yami smirked. 'Let's see if it works.'

Activating [Open Bones], Yami focused on his right arm. First, he broke it into two more joints, one in the elbow and the other in the upper and lower arm. 

Then he added more, breaking it into five and then seven joints. His arm twisted and bent, looking more like a sausage than an arm.

'Seven joints is the limit for now,' he thought. 

Yami pulled his arm back, winding it like a whip before launching the ball with terrifying speed.

BOOM! The ball vanished into the sky, leaving behind a sharp sound that echoed across the field. 

It wasn't a normal throw—it sounded like a gunshot and could very well have the force of one. 

Everyone stared at Yami silently as the Aizawa informed them of the distance.

"Damn," Kirishima muttered, wide-eyed staring at Aizawa. "You're a beast, man."

Even Bakugo couldn't hide his shock, though he quickly tried to mask it with a scowl.

"832 meters," Aizawa said lazily, not bothering to look up at Yami, "And why does it smell like?..."

But then the real shock hit.

Yami's arm hung limp at his side, completely mangled. The unnatural joints hadn't just broken to create the whip motion—they had shattered when Yami threw the ball. 

His skin stretched awkwardly over the broken bones sticking out at weird angles. His entire arm looked ruined.

"What the hell!?" Kaminari yelled, his face turning pale.

Midoriya gasped, clutching his notebook. "That… that can't be right. His arm is—"

Yami barely glanced at his broken limb, his expression was calm, almost bored. It hurt like hell, sure, but he'd felt worse during his own brutal training, hell, even using [Open Ribs] hurt more. 

Yami sighed and shook his head, muttering, "Guess I overdid it."

Before anyone could move, Momo was already walking toward him. She didn't look shocked or scared. In fact, she just sighed, shaking her head like this was the most normal thing in the world.

"So soon?" she said, sounding more tired than concerned.

Momo reached into her stomach, her Quirk activating as two slim metal sticks and a rope materialised in her hands. 

Without waiting for Yami to ask, she gently grabbed his arm.

"This might hurt," she warned.

Yami gave her a slight smirk. "Does it?"

With an extraordinary and probably traumatising ease, Momo slid the metal rods along his shattered bones, using the rope to secure them tightly in place. 

She didn't flinch at the grotesque sight or the blood dripping down his arm. She'd done this before—too many times, really. 

Accidentally breaking Yami's bones during training was pretty normal even when they were kids, and hitting him with tungsten batons on the chest was her way of teasing him.

Once the makeshift splint was secured, Yami petrified his arm to heal it intstantly. 

His skin hardened into smooth black stone, and the bones beneath began to knit themselves back together and into place.

The cracks sealed, and his arm returned to normal. But there was a problem since his skin was torn as much as his bones; the special cream had already been used.

Yami's skin, now unprotected after the petrification, began to burn under the sun. The exposed areas turned red as the sunlight hit Yami.

"Shit," Yami muttered, quickly repetrifying his arm to protect himself from the sun's deadly rays.

The class stared in stunned silence.

"Did he just… fix his arm?" Kaminari whispered.

"Why's he turning it into stone?" Mina asked, confused.

Even Aizawa-sensei raised an eyebrow, clearly interested. He walked over, stopping in front of Yami. "You're not going to finish healing it?"

"I would," Yami replied, flexing his petrified fingers. He had only petrified most of the skin except the joins. 

Yami could move his hand, but it felt like using an oversized boxing glove. "But sunlight burns me if I don't keep it covered. I'll keep it like this for now."

Aizawa nodded as if that answer made perfect sense. "Suit yourself."

The rest of the tests continued. Yami dominated every event, even with his petrified arm weighing him down. 

He used his left hand for most activities and barely seemed bothered by the injury.

During the grip strength test, Yami crushed the device with his left hand, shattering it into pieces.

"Oops," he said, smirking and looking at Momo as the broken grip tester sparked on the ground.

By the end of the tests, Yami and Momo were at the top of the leaderboard. No one else even came close. 

As the tests wrapped up, and Yami missed how Midoriya broke a finger, Aizawa finally addressed the class.

"Congratulations. None of you will be expelled… yet."

The students breathed a sigh of relief, yet somehow, Momo looked upset.

"But don't get comfortable," Aizawa warned. "This is only the beginning. If you want to survive at U.A., you'll need to push yourselves beyond your limits. Plus Ultra. Every day... well, I'm going off to nap."

Yami glanced at Momo, who was panting slightly from the last test... He hoped.

As they walked back toward the school building, Yami glanced at Momo, who was wiping sweat from her forehead.

"You did good," he said softly, patting her back.

Momo gave him a tired smile. "You did better, and I could've done better."

Yami glanced at his petrified arm, feeling its weight. "You know, you shouldn't put so much pressure on yourself," Yami said as he depetrified his arm slightly, but it quickly burned.

"Still burning?" Momo asked, her eyes flicking to his arm.

"A bit," Yami admitted as he turned his arm back into stone.

Momo reached out, gently squeezing his petrified hand. "I'll help you reapply the cream when we get home."

Yami smirked, leaning in close. "Thanks, cow."

Momo blushed deeply, biting her lip. "Stop calling me that…"