My Harem System In My Hero Academia

Yami woke up drenched in sweat, his body aching from the night before. Lying on top of him was Ochaco, completely knocked out, her breath slow and steady. 

His golden eyes trailed down to her soft body, her pussy still leaking his thick cum onto the sheets.

He carefully slid out from under her, sitting on the edge of the bed as he stretched his sore muscles. 

His throat felt dry, and he was about to look for some water when a soft knock echoed through the room.

Yawning, he walked over and opened the door. Momo stood outside, wearing nothing her tiny black bikini that barely covered her massive tits. 

Her dark eyes moved downward, landing right on his cock, still heavy and hanging between his legs.

"Well, now that's a good morning," she said with a smirk, her cheeks slightly pink. "You two were at it until three in the morning. I figured she'd need some rest, so why don't we train while she recovers?"

Yami nodded, pulling on a pair of black shorts before stepping outside. As he walked onto the beach, a familiar notification flashed before his eyes.

==== 

[Mission Complete: Hook, Line, and Sinker!] 

[Reward Unlocked: Quirk Upgrade – Elemental Battle Modes unlocked, including "Elemental Mode: Flame Mode".]

====

As Yami followed Momo onto the beach, the system screen popped up before him, its obnoxiously smug tone already getting on his nerves.

[Well, well, about time you unlocked Elemental Battle Modes. Now, this is where the path to the Ultimate Life Form truly starts.]

[Up until now? Your quirk techniques were complete dogshit compared to this. You went from being a pebble to—at best—a rock.]

Yami rolled his eyes. 'Thanks for the confidence boost,' he thought.

[You're welcome. So, what is an Elemental Battle Mode? Glad you asked, dumbass. It's a special fighting style built around different elements—fire, wind, light, and so on. Each one gives you a 'Mode.']

[Here's the lineup: Flame, Metal, Wind, Blacklight… and at the very pinnacle, Obsidian. If you live long enough to reach that level.]

Yami's interest piqued. 'Flame Mode, huh? What's the deal with that one?'

[Flame Mode lets you crank your body temperature up so high your blood literally boils—800 degrees Celsius, to be exact. You can then hurl that burning blood out like molten napalm, melting through anything it touches.]

Yami flexed his fingers, imagining the possibilities. That was a nasty upgrade.

[Oh, and you can temporarily boost your stats by using 'Gears,' kinda like that human condom—Fluffy?]

'Luffy,' Yami corrected with a sigh.

[Yeah, yeah, that guy. Except you won't look like a balloon animal when you do it.]

Yami and Momo stopped at the shore, the waves rolling in gently under the morning sun. 

Momo quickly slipped off her bikini, her smooth, flawless skin catching the early light. She placed her hands over her chest, her quirk activating as a thin layer of fabric spread over her body. 

In seconds, a snug sports bra and a pair of tight black shorts formed around her, hugging her curves in all the right places.

"Alright," Momo said, rolling her shoulders. "I've been training, and I need a test dummy—preferably one who can survive a grenade to the chest."

Yami smirked, stretching his arms as his golden eyes shamelessly trailed down her body. "What a coincidence. I came up with some new magic tricks myself," he said, his gaze lingering on her compressed tits. 

The sports bra did its best, but with a rack like hers, it was a losing battle.

Momo caught his stare and narrowed her eyes. "Eyes up," she said teasingly before casually pulling a kendo sword straight out of her cleavage.

Yami whistled, his smirk widening. "That's one hell of a weapon stash."

"The only sword that matters hasn't used it as a sheet," Momo said, gripping the hilt confidently.

Yami cracked his neck and then glanced at the sky. His eyes searched for a large cloud—something big enough to properly test his technique. "Hey, mind if I test something first?" he asked.

Momo raised an eyebrow but shrugged. "Why not?" She waved her hand, materializing a sleek pair of sunglasses before slipping them on.

Yami cracked his knuckles. "Let's see how this goes."

He activated Space Ripper Stingy Eyes. Blood surged to his eyes, the pressure building to an almost unbearable degree before two razor-thin beams shot out, slicing through the sky like a hot knife through butter. The attack tore through the cloud, leaving a perfect gap.

'Augh! What the hell?!' Yami clenched his eyes as a sharp, stinging sensation burned behind his eyes.

[Aye, stupid! Space Ripper Stingy Eyes—I'll just call it Space Ripper—fires pressurized liquid at high speeds. WHAT DID YOU EXPECT, DUMBASS? YOU HAVE TO SHOOT SOMETHING!]

Yami rubbed his temples as the system's screen appeared, even with his eyes closed. Oblivious to his internal struggle, Momo stepped closer, inspecting his face.

"Are you okay?" she asked, her voice softer than usual.

Yami exhaled sharply. "Yeah, I just need a sec." Without another word, he petrified his head for a moment to numb the pain, then quickly depetrified it.

"That was impressive," Momo admitted. "A ranged attack, huh? I wasn't expecting that."

Yami smirked. "Yeah, it's a new one. Now, do me a favor—help me put some of that cream on my face before I go blind from the sun."

Momo rolled her eyes but complied, creating and dipping her fingers into a jar of specialized sunblock Angela had given her and gently applying it to his face. 

Her hands were cool against his skin, and Yami found himself momentarily enjoying the sensation.

As she worked, Momo's brow furrowed. "I don't understand how your body works at all."

"Neither do I, honestly," Yami admitted. "I just roll with it; you can say I'm built differently."

She finished applying the cream and wiped her hands on her shorts. "Alright, enough warm-ups. Let's fight."

Yami grinned, standing to his full height. "You sure? You might end up on your ass or me in your ass."

Momo smirked. "I've gotten stronger."

Without warning, she lunged forward, her kendo sword striking at his midsection. Yami dodged effortlessly, twisting his body as her blade cut through the air.

"Faster," he taunted.

Momo narrowed her eyes and pressed forward, her strikes becoming sharper, faster. Yami continued dodging, reading her movements, but she was improving—her footwork was cleaner, her reactions quicker.

She feinted left before swinging upward, forcing Yami to block with his forearm. The impact made his muscles ripple, but out of pride, he didn't show it.

"Not bad," he admitted.

Momo didn't hesitate—she stepped back and slammed her free hand against her exposed stomach, activating her Quirk. A metallic staff formed in her grip, replacing the kendo sword in an instant.

"Oh?" Yami's smirk widened. "You finally switching up to metal?"

Momo twirled the staff and rushed forward again, thrusting it toward his gut. Yami leaned to the side, catching the staff in one hand.

But the moment he touched it, Momo released her grip and spun into a roundhouse kick aimed at his temple.

Yami ducked just in time, but her foot still grazed his hair.

"Nice," he admitted. "But not good enough."

Before she could react, Yami shot forward and grabbed her waist, lifting her clean off the ground. Momo yelped as he effortlessly carried her toward the water.

"Wait—wait, Yami—!"

Too late. He tossed her into the ocean.

Momo resurfaced seconds later, gasping. "You—!"

Yami laughed. "You need to be ready for everything, Cow."

Momo spat out a mouthful of water and wiped her face, her expression both annoyed and impressed. "Fine. Next round, no holding back."

"Now that's what I like to hear."

Yami wanted to test out Vaporizing Freezing. Not wanting to be caught off guard, Momo formed a tungsten bo staff, gripping it tightly as she rushed toward Yami. 

The two clashed, their movements fast and relentless, neither holding back as they exchanged blows.

Yami's golden eyes glowed as he dodged Momo's strikes, his muscles tightening each time her staff whistled past his face. 

He saw an opening and took it—his hand shot out, and in a split second, the tungsten staff in Momo's grip was covered in a thin layer of ice. 

It spread rapidly, frost creeping along the metal until it was frozen solid.

Momo barely had time to react before a sharp jolt ran through Yami's body, making his muscles seize up. A violent shock surged through him, crackling from the frozen weapon in Momo's hands.

Yami gritted his teeth, staggering slightly as the electricity coursed through him. "You booby-trapped your own weapon?" he asked, shaking off the lingering static.

Momo smirked, twirling the now-cracked tungsten staff in her hands. "You're not the only one with tricks," she said smoothly. "I had to memorize the molecular structure of electricity-conducting alloys for a physics exam last year. It turns out tungsten holds a charge beautifully when manipulated correctly."

Yami exhaled sharply, rolling his shoulders as he flexed his fingers, the remnants of the shock dissipating. "Guess I should've expected that from you, Cow."

Momo huffed but didn't argue, already forming a new weapon in her hands—a carbon-fiber spear this time, lighter but still resilient. "Ready for another round?" she challenged.

Yami grinned, raising his fists. "Let's go."

The following exchange was even more intense. Yami activated Vaporizing Freezing again, his fingertips turning blue as cold mist rose from his skin. 

Momo, anticipating another attempt to freeze her weapon, altered her approach—she didn't give him the chance. She feinted left before spinning low, sweeping his legs out from under him.

Yami barely managed to catch himself, planting his palm into the sand to flip upright. 

But Momo was already on him, her spear thrusting toward his chest. He twisted his body at the last second, avoiding a direct hit, but the spearhead grazed his ribs, leaving a sharp sting behind.

"You're getting faster," Yami admitted, licking his lips.

Momo adjusted her grip on the spear. "And you're still relying too much on brute force."

Yami laughed. "Guess I'll have to switch things up... Gear, Second!"

Before Momo could react, Yami activated Flamde Mode. His skin reddened, veins glowing faintly. 

The air around him grew hotter, steam hissing from his fingertips as he took a single step forward—and vanished.

Momo's eyes widened. She barely had time to raise her spear before Yami appeared behind her, moving too fast for her to track. 

She turned on instinct, swinging her weapon in a wide arc, but Yami ducked, closing the distance in an instant.

He caught her wrist, his grip strong but not crushing. "Checkmate," he said, his golden eyes locking onto hers.

Momo's breath hitched, her chest rising and falling rapidly as she realized she had no way out. 

Momo scoffed. "Fine," she sighed. "I'll call it a draw."

Yami released her wrist, stepping back. "Fair enough," he said. "But next time, no holding back." He said, then collapsed into the ground.

Momo smirked, wiping sweat from her brow. "Are you okay?"

Yami chuckled. "Absolutely not; I didn't know I could have frostbite and fever."

Momo put her bikini back on and sighed, looking down at Yami, who was lying in the sand in burrito mode, wrapped in his petrification using Flame Mode.

"You're pathetic," she muttered but still hoisted him onto her back, carrying him toward the house. As they walked, Momo smirked. "So, tell me, how does Ochaco's ass compare to mine?"

Yami groaned, his body still sore, but managed to answer. "Hers is fat, soft, and bouncy as hell, but yours is shaped better. More toned. You can take a pounding."

Momo nodded, satisfied. "Good. Well, please be honest with her. If she's hooked on your cock, she'll probably agree to be your sex-friend."

Yami chuckled. "Yeah, I think she'd be down for anything at this point."

When they finally returned to the house, Ochaco was already making breakfast. The smell of eggs and pancakes filled the air as she hummed softly, unaware of their conversation.

Yami and Momo sat at the table, digging into the food while Ochaco blushed under their praise. Momo, ever the perfectionist, gave a few pointers. "The eggs are good, but lower the heat near the end next time so they stay fluffy."

After they finished eating, Yami wiped his mouth and leaned back. "Alright, Ochaco. Time to be real with you."

Ochaco tilted her head, confused. "About what?"

Momo set her fork down and folded her hands. "Yami's probably going to end up fucking every girl in Class 1-A and 1-B."

Ochaco blinked, her face turning red as she processed what they just said. "Wait… every girl? Even the quiet ones? Even… Jiro?"

Yami smirked. "Especially Jiro."

Ochaco fidgeted, biting her lip. "And you're okay with this, Momo?"

Momo shrugged. "Of course. I know how he is, and I don't mind sharing if the girls are worth it."

Ochaco hesitated for a moment, then exhaled. "Well… I don't really mind either. I kinda expected it after last night."

Yami grinned. "Then welcome to the fun, Ochaco."

She blushed harder, but there was excitement in her eyes. "So… what now?"

"Let's just enjoy the rest of the day before we head back," Yami said, stretching his arms behind his head. "No rush."