Death wasn't supposed to be so abrupt.
Takeshi Nakamura had spent most of his thirty-five years pushing the limits of innovation. A top-tier engineer, he lived for the thrill of creation. From prototypes to polished designs, the world of technology felt like home. But no amount of knowledge could save him when a routine calibration turned into catastrophe.
"Careful with the voltage!" he shouted at his junior engineer.
The warning came too late. A crackling sound, followed by a blinding flash, tore through the lab. Takeshi's heart raced as the smell of burning circuits filled the air. Before he could react, a powerful current surged through the metal he was holding, and everything went dark.
Takeshi awoke in silence.
He couldn't see, couldn't move, and yet he was aware. His surroundings felt... wet? His lungs burned for air, his body constricted and unresponsive. Panic clawed at him until, suddenly, his world shifted, and he was thrust into blinding light.
The harsh cry of a baby broke through the air.
Takeshi—no, not Takeshi anymore—instinctively knew that the sound was his own. He had been reborn.
The weeks that followed were a whirlwind of overwhelming sensations. His vision was blurry, his limbs weak, but his mind—it was sharper than ever. His surroundings were unfamiliar, the people around him speaking a language he vaguely recognized as Japanese, but something was different.
It wasn't just the body he now inhabited; it was the world itself. The news broadcasts his parents listened to, the excited conversations about strange new abilities—quirks, they called them—all hinted at a reality he had once thought fictional.
A single revelation hit him like a lightning bolt.
I'm in a world of quirks.
His new parents, Hiroshi and Aiko Yamada, were kind but unremarkable. They lived in a modest house in a quiet neighborhood. Hiroshi worked long hours at a factory, while Aiko cared for their only child. Katsuo Yamada, as they called him, pretended to be the curious and playful child they expected, but behind his innocent façade, Takeshi's mind raced.
This world is completely different from my own. But if quirks exist, that means the rules of science have changed. What else is possible here?
Katsuo's quirk manifested early. He was barely three years old when the first signs appeared.
It started with the voice. A calm, synthetic tone that echoed in his mind as he played with his toys.
"Initialization complete. AI Chip online."
The flood of data was instantaneous. Formulas, equations, and raw information poured into his consciousness. It was as if a supercomputer had been hardwired into his brain. At first, the influx overwhelmed him, but the AI quickly adapted, organizing the data into manageable pieces.
Katsuo stared at his building blocks, astonished.
"Did I... just calculate the structural integrity of this tower before I built it?"
His mother noticed the change almost immediately. "Katsuo, sweetheart, how did you do that?" she asked, pointing to the perfectly symmetrical castle of blocks he had constructed.
"Just... thinking," Katsuo replied, his young voice careful.
The AI Chip became his silent companion, offering suggestions and solutions faster than he could process them on his own. By the time he turned five, he had mastered advanced mathematics, basic physics, and even begun dabbling in engineering—though he kept his abilities hidden.
His parents believed his quirk was something harmless, like enhanced memory or focus. Katsuo let them think that. The truth was far more dangerous.
One day, while playing outside, Katsuo witnessed something that cemented his determination to use his gift.
The sound of shouting drew his attention to the street. A teenage boy with smoke curling from his palms stood in the middle of the road, facing down a group of kids.
"You think you're better than me just because you've got flashy quirks?" the boy sneered. "Let's see how tough you are now!"
Flames erupted from his hands, causing the others to scatter. Katsuo froze, watching in horror as the fire crept closer to a nearby shop.
"Someone stop him!" a bystander cried, but no one moved.
Just as panic gripped Katsuo, a hero arrived. A man clad in blue and silver armor leapt into action, deploying a large shield that absorbed the flames. His movements were swift and calculated, the armor's mechanisms whirring audibly as he subdued the boy with a single strike.
Katsuo couldn't tear his eyes away. It wasn't the hero's strength or quirk that fascinated him—it was the technology.
"That shield," he whispered to himself. "It wasn't a quirk. It was... science."
Something clicked inside him.
That night, Katsuo began sketching.
His small desk was covered in loose papers as he scribbled frantically, the AI Chip organizing his thoughts into coherent designs. Inspired by the hero's shield, he envisioned gadgets that could enhance ordinary people, leveling the playing field in a world dominated by quirks.
"Quirks aren't everything," he muttered. "If I can combine technology with quirk usage... or even make it independent of quirks..."
The possibilities were endless.
By the time Katsuo turned six, his experiments had grown more ambitious. He scoured junkyards for parts, salvaging old appliances and electronics. His bedroom transformed into a makeshift lab, much to his parents' confusion.
"What are you making, Katsuo?" his mother asked one evening as he fiddled with a mess of wires and circuit boards.
"Just a game, Mama," he replied with a grin.
In truth, he was building his first prototype: a small drone inspired by the spider-like robots from a comic he remembered in his past life. The AI Chip guided him through the assembly process, highlighting errors and suggesting improvements.
When he finally powered it on, the drone hummed to life, its tiny legs twitching as it stood upright.
"It works," Katsuo whispered, a thrill of pride coursing through him. "It actually works."
But as much as he wanted to celebrate, he knew he had to keep his creations a secret. The world wasn't ready for what he could do—not yet.
One afternoon, Katsuo sat in the corner of the local park, sketching designs for a new project. His AI Chip had flagged a problem in his drone's energy efficiency, and he was brainstorming solutions.
"Hey, kid," a gruff voice interrupted.
Katsuo looked up to see a tall man clad in battered armor standing over him. It was Steel Fist, a small-time hero known for his raw strength and mechanical gauntlets.
"You're Katsuo Yamada, right? I heard about you from a friend." Steel Fist held up one of his gauntlets, the metal scorched and cracked. "Think you can fix this?"
Katsuo hesitated. He wasn't ready to reveal his skills to the wider world, but the challenge was too tempting to resist. "I can try," he said, keeping his voice steady.
Steel Fist handed over the gauntlet, and Katsuo examined it carefully. The design was primitive, relying on outdated tech to amplify the hero's punches.
"This is... inefficient," Katsuo muttered, already envisioning ways to improve it.
He worked late into the night, dismantling and rebuilding the gauntlet with salvaged parts from his stash. When Steel Fist returned the next day, Katsuo handed him a sleeker, upgraded version.
"What's this?" Steel Fist asked, inspecting the changes.
"Your gauntlet, but better," Katsuo replied simply. "I added an energy stabilizer to reduce overheating and reinforced the joints for higher impact resistance."
Steel Fist tested the gauntlet, throwing a punch that cracked the air like thunder. His eyes widened in awe. "Kid, you're a genius."
Word of Katsuo's skills spread quickly after that. Local heroes and even a few ordinary citizens began seeking him out for repairs and modifications. He kept his work low-profile, charging only small fees to fund his experiments.
But with recognition came danger.
One evening, while Katsuo walked home from the market with his mother, a man stepped out of the shadows. His face seemed to ripple unnaturally, his features shifting like liquid.
"Hand over your money," the man snarled, his voice low and menacing.
Katsuo's mother clutched his hand tightly, fear etched into her face. "Please, we don't have much—"
"Quiet!" the man snapped, his hands morphing into jagged claws.
Katsuo's mind raced. The AI Chip began simulating scenarios, calculating escape routes and potential outcomes. None of them were good.
Just as the man advanced, a blur of motion swept past them. A hero in bright yellow armor appeared, launching a beam of light that forced the villain back. The fight was over in seconds, but the encounter left Katsuo shaken.
He realized then that he couldn't rely on others to protect him—not in a world like this.
That night, Katsuo sketched furiously. His goal was clear: he needed tools to defend himself and those he cared about.
The result was his first personal invention: a compact, wrist-mounted energy shield. The design was inspired by the comics he loved in his past life, but adapted to this world's physics.
When he activated the device, a shimmering barrier appeared, its edges glowing faintly. Katsuo stared at it, a sense of accomplishment swelling in his chest.
"This is just the beginning," he whispered.
In the weeks that followed, Katsuo refined the shield and began working on new projects. He knew he was walking a fine line—his inventions had the potential to change the world, but they could also attract the wrong kind of attention.
As he gazed at the sketches covering his desk, Katsuo made a silent promise.
I'll use my knowledge to make this world better. And if anyone tries to stop me... they'll regret it.