Volatile Hearts (Bakugou Katsuki X OC)

Chapter 1: Transfer Sparks 💥 (pt 1)

The morning had been ordinary enough for Class 1-A. Kaminari was already complaining about breakfast portions, Mina was half-dancing in her seat to a song only she seemed to hear, and Bakugou had slammed his desk loudly enough to make Kirishima choke on his water.

So when Aizawa walked in, scarf trailing like a shadow, no one expected the girl at his heels.

Her presence was impossible to ignore. Dark hair fell in sharp layers against pale skin, threaded with auburn glints that caught the light each time she moved. Her hazel eyes, flecked with green, scanned the room with unflinching precision—not curious, not shy, but challenging, as if daring anyone to speak first. Her posture was straight, deliberate, chin tilted just high enough to suggest she didn’t care if the world loved or hated her.

Even Mina, who prided herself on being unflappable, whispered a startled, “Whoa.”

“This is your new classmate,” Aizawa announced, voice as flat as ever. His tired gaze swept the room before returning briefly to the girl at his side. “Madolyne Yoshida. You’ll treat her the same as anyone else.”

The girl arched one brow. Her lips curved into a smirk that was somehow both amused and sharp. “It’s Maddie,” she corrected easily, hands slipping into her pockets. “Madolyne is for when I’m in trouble.”

That little flicker of confidence rippled through the room like a spark. Kirishima grinned wide. Mina gave an approving “Ooooh, bold.” Kaminari snorted under his breath. Even Todoroki’s heterochromatic eyes lingered a second longer than usual.

But the sound that cut through louder than the rest came from the back row.

“Tch.”

Bakugou Katsuki’s scowl was legendary by now, sharp enough to slice glass. His arms were crossed, his ash-blond hair sticking up in its usual spiky mess. Red eyes narrowed with immediate irritation.

“Great,” he growled, his voice dripping disdain. “Another damn extra.”

The tension that thickened in the air was almost physical. Maddie’s hazel eyes snapped toward him, and for a heartbeat the world seemed to still.

Then—slowly, deliberately—she smirked. “I’ll take that as a welcome.”

“Don’t flatter yourself,” Bakugou spat back, palms already crackling faintly with sweat-fueled nitroglycerin.

If Aizawa was bothered, he didn’t show it. He simply muttered, “Pick an empty desk,” then buried half his face in his scarf as though preparing for the inevitable headache.

Maddie slid into a seat near the middle row without hesitation. She ignored the whispers that followed her like a trailing echo—She’s Aizawa-sensei’s niece? Her dad was a hero? Why now?—and instead flipped open a sleek black notebook, already jotting notes in tidy, efficient handwriting.

Bakugou, however, kept glaring.

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The day blurred with lessons—Heroics, Mathematics, English—but Maddie remained sharp in everyone’s peripheral vision. She answered questions crisply, her accent only faintly American, her confidence unshaken even when Present Mic shouted encouragements half a foot from her desk. She didn’t flinch, didn’t shrink.

It was only during training that the real fireworks began.

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Ground Beta stretched out beneath a sky painted pale blue, concrete towers and alleys rising in uneven clusters. The air smelled faintly of scorched stone, lingering proof of how many times it had been rocked by Bakugou’s explosions.

Aizawa stood at the edge, hands deep in his pockets. “Pair exercises,” he muttered. “Yoshida, demonstrate.”

The class turned, curiosity buzzing like electricity. Maddie only smirked, shrugging out of her jacket and tossing it aside. “Gladly.”

“Who’s the volunteer?” Aizawa asked lazily.

Sero blinked, pointing to himself. “Wait, what—”

But Maddie had already moved. Her hand brushed his arm lightly, almost casual. In that instant, her body rippled. Her skin shimmered as if catching a reflection of water, her height shifted, her jawline softened—

And suddenly, it was Sero’s grin flashing back at them.

Gasps erupted across the group.

“Holy crap!” Mina squealed, clapping both hands over her mouth.

“That’s—!” Deku’s pen flew across his notebook, frantic scribbles filling the page.

Sero stumbled back, wide-eyed. “Uh—hey! That’s me!”

Tape shot cleanly from Maddie’s elbows—identical to his quirk, precise and controlled. She yanked a nearby training dummy, immobilizing it with clean, tight wraps before letting the tape retract. Then, with a shimmer, her body rippled back into her own form, hair falling loose around her face once more.

“Neat trick,” Kaminari muttered, jaw slack.

“I can borrow quirks,” Maddie explained simply, brushing a stray strand from her cheek. “And appearances.”

“Like Monoma and Toga mixed together,” Jirou whispered.

“Except cooler,” Kirishima added, his grin so wide it looked painful. “That’s crazy manly.”

Bakugou’s scowl deepened, his palms already fizzing with sparks. “Cheating, more like. You think copying makes you strong? Fight me without stealing!”

Maddie turned toward him, unbothered by the fury blazing in his eyes. Her smirk widened, sharp and feral. “Fight you?” she asked, her voice dipped in challenge. “Gladly.”

The air between them snapped, the static of two storms colliding. Heat rolled off Bakugou’s palms, while Maddie’s eyes glowed with something equally dangerous. Neither backed down.

Aizawa pinched the bridge of his nose. “Perfect,” he muttered. “Looks like I’ve found Bakugou’s new training partner.”

“What?!”

Their voices rose in unison, sharp enough to make half the class wince.

But the decision was made. And as the sun beat down over Ground Beta, every single student knew: this was the start of something explosive.

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Part 1 End (906 words)