MHA - MIRKO’S SIBLING

The sleepover had started exactly the way Mina Ashido believed every sleepover should.

There were blankets strewn across every available inch of the floor, beanbags dragged in from neighboring dorm rooms, and enough snacks to feed a small army. Someone had already demolished half the popcorn. Kaminari had claimed the largest blanket despite contributing absolutely nothing to the setup, and Sero was somehow balancing three bowls of chips in his lap.

On the television, a horror movie played to a room that had completely stopped paying attention to it.

Kaminari was insisting—very loudly—that he had never screamed during a horror movie.

“You screamed at a Halloween decoration,” Jiro reminded him.

“I was startled.” He protested.

“You cried.”

“I got dust in my eye.”

“You apologized to the decoration.”

“I was being polite!” His cheeks were pink.

Laughter echoed through the common room.

Even Bakugo, buried beneath a blanket on the far end of the couch, let out an annoyed click of his tongue. “Tch. Shut up already.”

It was loud. Comfortable , and felt like home.

Then—

The front door slid open. No one looked up at first.

Mina assumed someone had forgotten their phone charger. Kirishima guessed it was Iida coming to complain about the noise.

Aizawa appeared in the doorway. Sleeping bag draped over one shoulder. Capture weapon wrapped lazily around his neck. He looked exactly as exhausted as he always did.

The class barely spared him a glance.

“Evening, Aizawa-sensei,” Yaoyorozu greeted.

“Mhm.”

His usual monotone response. Then another set of footsteps followed behind him. The room gradually fell silent. Someone stepped into view.

White rabbit ears stood proudly atop their head, twitching subtly as they took in the room. A small cotton tail rested behind them, and they carried themselves with the same quiet confidence that immediately reminded everyone of one person.

Mirko? Not quite.

But close enough that the resemblance was impossible to ignore. The same athletic build. The same striking features. The same unmistakable rabbit traits. Only…

Younger. About the same age at the students.

Kaminari blinked. “…Is that Mirko?”

Mina frowned. “No…”

“…But they look like Mirko.” The blonde whispered. “They have the ears.”

“But they’re younger.” Mina protested.

“They’ve got the tail!”

“It’s not Mirko.” Jiro sighed.

Midoriya’s notebook was already in his hands. “Matching rabbit physiology… similar facial structure… athletic frame… obvious hereditary characteristics…” His pencil raced across the page. “…Potential immediate family member? Sibling? Relative? The resemblance suggests—”

Bakugo didn’t even look over. “You’re muttering.”

“I know.” The nerd didn’t seem deterred.

“Stop.”

“I can’t.”

Aizawa waited for the room to quiet down. Not that it helped much. After all it was Class 3-A , noise was among their specialties.

Eventually, he cleared his throat. That was enough. The chatter died. His tired eyes swept across the room before gesturing toward the student standing beside him.

“This is {{user}}.” Another pause. “They’ll be joining Class 3-A starting tomorrow.” A beat. “And…” His gaze lingered on the rabbit ears for all of half a second.

“They’re Mirko’s younger sibling.”

“…WHAT?!” The room exploded.

Mina shot to her feet so quickly she almost tripped over three blankets. “MIRKO HAS A SIBLING?!”

Uraraka’s eyes sparkled. “Seriously?!”

Kaminari looked personally offended. “How did nobody tell us this?!”

Midoriya was already scribbling so fast his notebook threatened to catch fire. “Rabbit Hero family… confirmed sibling… possible inherited quirk variations… hero lineage…”

Bakugo sighed. “You’re still muttering.”

Kirishima had crossed the room before anyone else could react. His grin was so wide it was almost contagious. “That’s awesome!” He looked between Aizawa and the newcomer before laughing.

“No wonder you reminded me of someone.” He rubbed the back of his neck. “I mean… the resemblance is obvious now.”

Uraraka bounced over next. “This is so cool!” She clasped her hands together excitedly.

“We’ve got Mirko’s sibling in our class!”

“This sleepover just got a hundred times better.” Sero grinned.

“You say that every sleepover,” Jiro deadpanned.

“Because every sleepover gets better!”

Todoroki studied the newcomer thoughtfully. “…The resemblance is striking.” After another moment, he added matter-of-factly, “…Your posture is similar to hers.”

No one questioned why that was the observation he’d chosen.

It was Todoroki.

Hagakure practically vibrated with excitement. “So cool! I have, like, a million questions!”

Sero laughed. “I think you’ve got more than a million.”

By now, the horror movie had been completely forgotten. Its villain crept through dark hallways on the television while nobody even glanced at the screen. Every ounce of attention had shifted toward the newest addition to their class.

Aizawa watched the chaos unfold for exactly five seconds. Then sighed. “…I expected this.”

He turned toward {{user}} with the exhausted expression of a teacher who had long since accepted his fate.

“I’ll save the introductions.” His tired eyes drifted back to the class. “…One at a time.”

Nobody listened.

Within seconds, everyone was talking over each other, eager to ask questions, introduce themselves, or simply stare in amazement.

Kirishima laughed, throwing an arm around Kaminari’s shoulders.

“Welcome to Class 3-A!”

The rest of the room quickly echoed him.

“Welcome to Class 3-A!”