The tension in the room was electric.
The wide training space inside Rumi's rooftop home was bare save for reinforced flooring and a few scuffed walls—every mark a testament to past battles. Sunlight filtered in through the windows, catching the faint dust in the air. Neither of them moved at first.
Rumi crouched low, weight forward, muscles coiled tight like a spring. Her crimson eyes were locked onto Izuku with predatory focus, lips curled into a feral grin. Every inch of her posture screamed hunter.
Izuku, in contrast, stood upright and loose, shoulders relaxed, hands raised casually. No tension. No wasted movement. His breathing was slow, even—almost bored.
Then—
BOOM.
The floor cracked beneath Rumi's foot as she launched forward, her body exploding into motion like a cannonball. The sheer force displaced air in a violent ripple.
Izuku's head shifted a few centimeters to the side.
WHOOSH!
Her kick sliced through empty space where his face had been a fraction of a second earlier, the wind pressure snapping his hair back.
"Fast," Izuku muttered, eyes sharp as they tracked her trajectory.
Rumi landed in a low crouch and didn't stop—she spun immediately, her leg whipping around toward his ribs.
THUD!
Izuku caught her shin with one hand. The impact echoed through the room, the force rattling the reinforced floor beneath his feet.
"Oh?" Rumi grinned, fangs flashing. "Not bad."
She pushed off her planted leg and flipped backward, twisting midair to wrench herself free. Her hands touched the ground for a split second before she cartwheeled out and sprang forward again, heel cutting down toward him like an axe.
SWISH!
Izuku tilted his torso just enough for the strike to graze past him, the air pressure snapping his gym shirt like a flag. He stepped inside her reach and snapped a sharp jab toward her stomach.
BAP!
Rumi twisted at the last second, his fist grazing her side. She immediately latched onto his arm, using his forward momentum to fling herself upward. Her thighs clamped around his neck mid-motion, locking in tight as she tried to drag him down in a brutal scissor hold.
Izuku chuckled, unfazed. "Again with this?"
He dropped his center of gravity and rolled with the motion, breaking the angle before she could secure the lock. Rumi released and landed smoothly on her feet, clicking her tongue in annoyance.
"Tch. Sharp reflexes."
Izuku didn't give her time to reset.
He lunged forward, fists moving in a controlled blur—precise, efficient, relentless.
BAM! BAP! WHISH!
Each strike forced Rumi back. She blocked and parried on instinct, forearms taking the brunt as her feet barely touched the ground before she was airborne again. Using a powerful rabbit-like burst, she twisted mid-air and drove both feet down toward him.
CRACK!
Izuku crossed his arms just in time. The impact sent him sliding back across the mat, boots grinding as dust scattered around him.
He rolled his shoulders once, shaking off the sting. "Nice kick."
"I've got plenty more," Rumi replied, already charging again.
This time she went low, sweeping hard for his ankles.
Izuku hopped clean over it, twisting midair—but Rumi had already read it. She exploded upward, knee driving straight for his core.
THUMP!
Her knee smashed into his forearm as he blocked, the vibration humming through his bones. Izuku pivoted instantly, slipping behind her and planting a clean, compact body shot between her shoulder blades.
BAM!
Rumi stumbled forward a step, then spun with the momentum, heel snapping out toward his head. Izuku ducked beneath it, pivoted, and rose with a sharp uppercut.
WHAM!
She barely crossed her arms in time. The blow lifted her clean off the ground, sending her skidding across the floor before she landed on her knees, breath heavy—but her smile never wavered.
"You're enjoying this way too much," Izuku said, shaking his head with a smirk.
"Damn right I am!" Rumi barked back, crouching low again, ears twitching with excitement. "You're the first kid I've met who doesn't crumble the second I get serious."
Izuku flexed his knuckles once, stance still calm—but now his eyes were sharper, more focused. "And you're the first person who's actually making me think about my movement instead of reacting. Guess we're even."
Rumi's grin stretched wider, wild and satisfied. "Then stop holding back, Izuku. I wanna see just how far that strength really goes."
The air between them tightened again.
For a split second, there was nothing—no sound, no movement—just two predators measuring each other.
Then Rumi vanished.
She didn't rush straight in this time. She hunted.
Her foot slammed into the wall, launching her sideways, then another kick sent her flipping overhead. She rebounded off a pillar, twisted midair, and came down at an angle that would've caught most fighters completely blind.
Izuku's eyes tracked everything.
BAP! WHISH! CRACK! BOOM!
Her heel skimmed past his jaw—he leaned back just enough. Her elbow snapped in—he parried it aside. A knee drove toward his ribs—he checked it with his thigh.
The rhythm of the fight escalated, the room filling with sharp impacts and shockwaves. Rumi fought like a storm—unpredictable, relentless, chaining movements together with animalistic ferocity. She didn't stop to reset, didn't hesitate, didn't breathe unless she had to.
Izuku matched her step for step.
Not with raw aggression—but with precision.
Every movement was economical. Every dodge placed him exactly where he needed to be. His strikes came in tight arcs, fists and feet snapping out like punctuation marks in a sentence he'd already written.
She leapt off the wall again, spinning low—
Izuku slid beneath it.
She twisted midair, bringing both heels down—He sidestepped, the impact cracking the floor where he'd stood.
She came at him again, faster, ears flattened back, grin feral.
And then—she overcommitted. Just a fraction. Just enough. Izuku stepped into her guard. His shoulder rolled. His hips turned. And his right fist came forward.
BWOOM!
The punch stopped less than an inch from her face. But the force didn't. The air detonated.
Rumi's hair whipped violently backward, the pressure rippling through her like a shockwave. The wall behind her spiderwebbed with cracks, dust raining down as the room groaned in protest.
She froze.
Eyes wide. Breath caught halfway in.
Slowly—very slowly—Izuku pulled his fist back, unclenching it as if nothing had happened.
"If I hadn't stopped," he said calmly, voice steady despite the adrenaline humming under his skin, "you'd be on the other side of the wall."
For a heartbeat, there was only silence.
Then Rumi threw her head back and laughed, loud and raw, her chest heaving as adrenaline burned through her veins.
"Hah! You cocky little bastard!" she barked, wiping sweat from her brow. "Alright—I'll give it to you. You're the real deal."
Izuku relaxed, lowering his guard completely. His posture softened, a faint smile tugging at his lips. "You're not too bad yourself."
She straightened, rolling her shoulders, her smirk returning—sharp, wild, unmistakably Mirko.
"Not too bad?" she echoed, amused. "You've got nerve, kid."
She stepped closer, crimson eyes gleaming with excitement. "Better get used to this. Tomorrow, I won't let you stop short."
Izuku met her gaze, unbothered, a spark of anticipation flashing behind his eyes.
"Good," he replied. "I'd be disappointed if you did."
The room was quiet again—but this time, it wasn't tension. It was mutual respect. And the promise of something far more brutal waiting just around the corner.
After their spar, Rumi and Izuku sat together on the couch, their bodies still humming from exertion. Sweat clung lightly to their skin, hair damp and slightly unruly, the faint scent of metal and ozone from the training room lingering in the air. The adrenaline that had fueled them minutes ago was fading, replaced by a mellow, almost drowsy calm.
For a moment, neither spoke.
Rumi leaned back first, one long, toned arm draped lazily across the backrest, her posture relaxed but alert in that unmistakable way only seasoned fighters carried. Her ears twitched once, then stilled. Izuku sat beside her, elbows resting on his knees, fingers loosely interlaced as his breathing evened out. His chest still rose a little faster than normal, but his expression was peaceful.
What surprised Rumi wasn't his strength—that part she'd already confirmed.
It was how easy this felt.
Talking to people usually took effort. Most either tried too hard, acted intimidated, or couldn't stop posturing. Izuku did none of that. He just… existed. Comfortable. Grounded. Like he wasn't trying to impress her—or anyone.
"…How is life as a pro hero, really?" Izuku asked at last.
His voice was quiet, almost thoughtful, and his eyes were on the ceiling as if the answer might be written somewhere between the cracks. It wasn't the kind of question fans asked. There was no awe in it. Just curiosity.
Rumi exhaled slowly through her nose. A smirk tugged at her lips out of habit, but it softened as she actually thought about it.
"It's loud. Messy. Never-ending," she said. "You finish one fight, and three more are waiting. Villains don't take breaks, and paperwork sure as hell doesn't either. You're sore most days, exhausted the rest." She tilted her head slightly, ears flicking. "But when you stop someone. When you really save them—see their shoulders drop, see them breathe again…"
She shrugged lightly. "That part sticks. Makes the rest worth it."
Her gaze shifted toward him. "You mess up sometimes. People get hurt. Some things don't go the way you want. But you don't get to stop. You just… carry it and keep moving."
Izuku nodded slowly, absorbing every word. He didn't interrupt. Didn't rush to respond. He just listened.
"I think," he said after a moment, "that's what scares people the most. Not failing—but knowing you still have to move forward afterward."
Rumi blinked, then laughed quietly. "Damn. You really are older than you look."
She flicked his arm with two fingers, not hard—just enough to break the heaviness. "Careful, kid. Say stuff like that and I'll start expecting you to complain about your back."
That finally pulled a grin from him. "Give it a few years."
The silence that followed wasn't awkward. It settled naturally, like a shared exhale.
Then Rumi pushed herself up with a stretch, spine arching as her muscles loosened. "Alright. Enough thinking." She glanced toward the kitchen. "We're gonna need more food if you're staying here a week. You eat like someone who breaks concrete for fun."
Izuku stood as well, grabbing a towel from the nearby chair. "Fair. Let me shower first though. I'm still half a battlefield."
"Same," she said, eyes glinting with mischief. "Wanna bathe together?"
It was clearly bait.
Izuku didn't miss a beat. He met her gaze evenly. "Sure. As long as you're willing to wash my back."
For just a split second, Rumi froze.
Then she scowled. "Tch. You're supposed to panic. Or blush. Or choke on your words."
He chuckled softly, slinging the towel over his shoulder. "Guess I'm bad at following expectations."
She clicked her tongue, but her grin came back sharp and competitive. "Heh. Fine. I'll break you eventually."
Izuku glanced back at her from the doorway, eyes amused. "Looking forward to the challenge."
The door slid shut behind him, leaving Rumi standing there with her arms crossed and an uncharacteristically warm expression on her face.
"…Troublemaker," she muttered. But she was smiling, she really enjoyed a challenge.
TO BE CONTINUED