Training
The sun had long set over Musutafu, casting the Karasuma family training yard in pale silver light. Most students were home by now, doing homework or scrolling through their phones.
Shin Karasuma was not most students.
A sudden crackle filled the air—lightning burst from Shin's forearms, trailing down his fists as he launched into a spinning elbow strike that cracked the training dummy's reinforced rubber surface. The dummy sparked from the impact, its chest cavity glowing faintly with residual electricity.
"Still too much discharge," Shin muttered, shaking out his hands. "Need better control during rotation."
He stepped back, breathing calmly, his storm-gray eyes sharp and focused. His black tank top clung to his frame, soaked with sweat. His muscles burned—not from overuse, but from constant, brutal repetition.
A beep sounded from the tablet resting on a bench nearby. The screen showed several video clips—martial artists, pro heroes, anime fight scenes.
On screen, a certain red-haired swordsman performed a spinning uppercut with chi-enhanced speed.
Shin watched, paused, and nodded.
"Got it."
He turned back to the dummy. Lightning surged again—but this time, it was tighter, coiled around his shoulders like a storm waiting to explode.
He stepped in.
Elbow. Knee. Twist. Sweep.
The combo flew together like muscle memory, powered by both skill and lightning.
CRACK!
The dummy's head snapped back, its base sliding an inch from the force.
"Still stiff on the knee pivot," Shin muttered. "Need to borrow more from taekwondo."
He backed off, then assumed a different stance—looser now, bouncing slightly on the balls of his feet. His arms came up, boxing-style.
"Muay Thai for the clinch… boxing for counters… taekwondo for evasive speed."
He visualized his opponents. Bakugou's explosive charges. Midoriya's relentless pursuit. Even villains from the future.
He couldn't afford to waste potential.
The next combo came faster—jab, feint, duck, cross. Low kick. Step in. Rising knee charged with electricity.
"Volt Knee!" he called out.
The impact shattered the dummy's chest plate, lightning bursting through like a cannon shot. The machine sparked and died with a mechanical whine.
Shin lowered his leg slowly.
"That one's a keeper."
His breathing was steady despite the heavy exertion. Years of training his body had made it second nature.
In the corner of the yard, an old metal pole stood tall. He walked over to it, pressed his palm against it, and focused.
Lightning crackled across his arm—then vanished.
"Flow. Don't fight it."
He exhaled, then slowly sent a thin current into the pole. The light flickered evenly, softly.
This was one of his daily drills. Energy control. Precision.
He glanced at a diagram sketched on the concrete wall nearby. A hero pose from an anime he loved—lightning laced through the character's legs as they dashed forward with raw power.
"…Maybe I can fuse the Flash Step idea with electromagnetic repulsion."
He crouched low. Charged his heels.
"Thunder Step…"
BOOM.
He vanished in a burst of static, reappearing ten meters away with a bang and a streak of black lightning in his wake.
He stumbled slightly. "Too much rear force. Need to adjust angle."
A voice called out from the side.
"You're gonna break the fence if you keep blasting around like that."
Shin turned—Yuki was perched on the wall, waving a rice ball at him like a flag.
"I brought snacks!" she chirped. "And also earplugs, because your punches are really starting to sound like grenades."
Toma's head popped up behind her, barely awake. "Are we training or watching anime in real life?"
Shiro followed quietly, holding a bottle of water. "You've been out here for hours."
Shin rubbed the back of his neck, smiling faintly. "Just refining stuff. Figured if I ever fight someone like Bakugou, I'll need both speed and precision."
Yuki threw him the rice ball. "Then take a break, voltage boy. You're gonna burn out before we even hit U.A."
He caught it easily. "Fine. But only for ten minutes."
Shiro handed him the water. "Your technique's evolved. That knee strike looked like something out of a pro fight."
"It's based on a mix," Shin said, thoughtful. "Muay Thai's clinch gives it the setup. Boxing gives me control. Taekwondo gives me escape. Add my quirk to the finish."
Toma raised an eyebrow. "You sure you're not secretly a reincarnated martial artist or something?"
Shin just grinned. "Something like that."
---
Later, when his friends had gone and the stars were out, Shin stood alone again.
He centered himself. Remembered the world he was born into. Remembered how it would change.
And then he moved—fluid, relentless, combining everything he'd mastered.
Each strike sparked the air. Each step echoed with force. He trained like a storm learning how to walk.
And in the quiet between the thunder, Shin whispered:
"I'll be ready."
******
The yard was quiet again. Midnight air chilled the sweat on Shin's skin as he crouched low, eyes closed.
His breathing slowed. His hands hovered just above the dirt.
He let his quirk spread—not to attack, but to listen.
Electricity buzzed faintly through the wires under the street. Static clung to his skin like fine mist. He could feel the world's energy breathing.
"Electricity isn't just power," he muttered, brow furrowing. "It's perception. Transmission. Sensation."
He inhaled deeply, letting tiny electromagnetic pulses radiate from his skin in expanding waves. They bounced off metal, concrete, even faint bioelectric signals in insects crawling under the ground.
Tsszzzt.
A sudden surge of clarity hit him—like his brain just tuned in to a different frequency.
In his mind's eye, he saw it: the soft thrum of Yuki's energy signature far off, faint sparks of static in the metal roof nearby, the steady rhythm of a bird's heart in a tree above him.
"…It worked."
He opened his eyes, grinning.
"Electrosense: Raijin's Whisper."
It wasn't just sight anymore. It was feeling, awareness—like radar made of lightning.
He reached for a pencil and flipped to a blank page in his training notebook. He began to scribble names and notes rapidly.
---
Technique Development Notes
1. Volt Knee – A thunder-boosted rising knee strike. Muay Thai inspired. Can disable or launch targets.
→ Variant: Volt Knee: Skybreaker (with a jumping spin)
2. Thunder Step – Short-range lightning-boosted dash. Quick burst movement using electromagnetic repulsion.
→ Variant: Thunder Step: Arc Dash (chain dashes mid-air or over walls)
3. Static Field – Generates a faint electric aura to sense and react to incoming movements or attacks.
→ Upgrade path: Raijin's Whisper (passive radar sense via electromagnetic feedback)
4. Lightning Clinch – Muay Thai clinch augmented by electric surges. Temporarily disables enemy muscle response on contact.
→ Variant: Storm Lock (used to trap and deliver multiple charged strikes)
5. Spark Rebound – Uses an opponent's attack to trigger an electromagnetic redirection, allowing for sudden counters.
→ Based on boxing counter styles.
---
Shin finished writing, flipped the notebook closed, and stood.
"All right…" he said to himself. "Let's try a full combo."
He stepped into the center of the yard, powered up—zzzzkkt—his limbs lit with a contained hum of lightning.
Thunder Step. He vanished in a blur, reappearing with a hard crack of displaced air.
Spark Rebound. He twisted mid-dash, imagining a punch, and redirected the momentum into a backward roundhouse.
Lightning Clinch. He shifted into a clinch stance, pulling an invisible opponent close.
Volt Knee: Skybreaker! He leapt with explosive force, lightning trailing up his leg like a dragon's tail.
The air split with a sharp BOOM as his knee slammed into the reinforced dummy's neck. It shattered.
Smoke rose.
His chest heaved, and he grinned through the lightning dancing in his eyes.
But more than the power—he felt the awareness now. With Raijin's Whisper active, he could feel the echoes of his own energy bouncing off every surface. He could track movement with his eyes closed.
This wasn't just offense anymore.
It was the birth of combat instinct through lightning.
---
Later that night, he sat cross-legged in his room, a soft electric hum around him. He watched raindrops patter on the window.
With eyes closed, he reached out again with his electrosense. Traced every drop before it hit the glass. Mapped the street below. Tracked the quiet hum of his mother's old radio two rooms down.
He was becoming more than just strong.
He was becoming aware.
*******
Timeskip one month
Shin stood on the cliffside of the old training gorge, the same place he'd nearly electrocuted himself in when he first awakened his quirk.
The winds howled. Clouds churned overhead like a brewing storm—fitting.
He looked down at his arms, where lightning coiled in arcs over his forearms and shoulders. He flexed his hands.
"Speed, power… that's not enough anymore," he muttered. "I need presence. I need to own the sky."
---
Goal 1: Mid-Air Lightning Strikes.
He took a running start—Thunder Step: Arc Dash—and leapt.
Mid-air. No ground. No point of contact. Normally, lightning needs a path—something to ground to.
But Shin? He wasn't normal.
He concentrated, forcing the lightning into his legs, then out through his core.
"Raijin Fang!"
He thrust one hand downward as he rotated mid-air. A spear-like bolt crackled into existence and launched downward—but it fizzled out halfway to the target.
He crashed into the dirt, rolling through the landing, coughing up dust.
"Damn—no grounding means no discharge. Need a channel."
He tried again. Again. And again.
Each time, he forced the electricity to cut through air like a blade, not find the ground like a river. His body ached. His muscles burned.
Then it hit him.
"My strength quirk…" He clenched his fists, sparks lighting up his arms. "It's not just external. It reinforces everything—even my cells. Even my control."
That was the key.
He jumped again.
This time, instead of releasing, he compressed. Lightning coiled in his arm like a coiled spring. Then—
"Raijin Fang: Sky Bolt!"
He threw the compressed charge like a javelin. A straight shot—pure white—sliced through the sky and exploded into the dummy below, obliterating it in a thunderclap that echoed through the gorge.
Shin landed. Hard. But he stood, chest heaving.
He smiled.
Mid-air strike: unlocked.
---
Goal 2: Lightning Armor Mode.
This one was harder.
He'd seen anime characters coat themselves in energy before. Lightning armor, aura armor, elemental exoskeletons—it always looked cool. But this was different.
This was real.
The first time he tried it, the lightning just scattered off his skin.
The second time, he managed to form a partial barrier—but it shocked his own nerves and made his arms numb for five minutes.
He paced the training ground, sparks flicking off his fingertips like static.
"I need insulation… but also integration."
That's when he realized—his body already had the durability, thanks to his dad's strength quirk. His bones were denser. His muscles, more resistant to stress. He could handle more power than normal people.
So what if he stopped treating the lightning like armor, and more like an extension of his muscles?
He dropped into a stance. Focused. Controlled his breathing.
"Let's go."
The lightning crawled across his skin, gathering along his arms, chest, and legs. It hummed against his enhanced muscles—no longer trying to force its way out, but syncing with him.
One pulse at a time.
"Raijin Mode: Surge Veil."
CRACK-BOOM.
A pulse of static burst outward, and when the dust cleared—he was glowing.
Not like an overcharged battery, but like a walking storm. Lightning flowed smoothly over his form, wrapping around his muscles, flowing with his movement like a second skin.
He stepped forward, then vanished—
BOOM!
He reappeared on the far end of the field, his foot buried in the side of a reinforced wall.
His speed—tripled.
His strength—magnified.
His awareness—flawless, thanks to Raijin's Whisper.
But it drained him fast. This wasn't a form he could hold long.
He collapsed to one knee, grinning through the exhaustion.
"I'll improve it... refine it. But I've made it. This is only the beginning."
---
Current Shin Karasuma Technique List:
- Raijin's Whisper – Electrosense. Can detect lifeforms and movement via electric fields.
- Thunder Step / Arc Dash – Short burst movement using electric repulsion.
- Volt Knee / Skybreaker – Electrically charged rising knee strike.
- Lightning Clinch / Storm Lock – Muay Thai clinch amplified with paralyzing currents.
- Spark Rebound – Counter style using redirection and electric burst.
- Raijin Fang: Sky Bolt – Compressed lightning spear thrown from mid-air.
- Raijin Mode: Surge Veil – Temporary lightning armor that enhances all physical stats.