The air in the Rokujo apartment was thick with dust motes dancing in the single shaft of morning light. Kenzou Rokujo, all of eight years old, sat cross-legged on the worn carpet, knees pressed into his chest. His eyes, usually a dull, thoughtful brown, were wide and luminous, reflecting the blue light of the ancient television screen.
On the screen, a figure stood silhouetted against a setting sun, a cascade of green hair whipped by the wind. It was Deku, the retired Number One Hero, now a living legend whose iconic fights were rerun daily as inspirational programming. The specific clip Kenzou was watching was known as the "Kyoto Save," a moment from years past where Deku had pushed his body far beyond its limits to stop a colossal earthquake Quirk.
"He did it," Kenzou whispered, his throat tight with awe. "He always did it."
A boy with a flashy electric Quirk lived next door. He often snorted when Kenzou's mother mentioned her son's Quirkless status. "Heroes need powers, Auntie. You can't catch a villain with a sneeze," the boy had once said, sparking a small, quiet anger in Kenzou's small chest.
But Deku… Deku was different. The historians always made sure to mention Deku's humble, powerless beginnings. Kenzou focused on the words of the commentator: "Midoriya, at a young age, proved that spirit and sacrifice were just as vital as any powerful Quirk. He trained his body into a weapon capable of housing the strength he would later inherit."
Kenzou didn't need the inheritance part. He latched onto the phrase: "trained his body into a weapon."
He sprang up, filled with a sudden, decisive energy. He marched to the kitchen, grabbed a notebook and a cheap pencil, and began to write, his tongue sticking out in concentration.
Goal: Become a hero like Deku!
Below that, he drew a small, crude picture of a muscular stick figure with a determined smile. Beside it, he wrote the first line of his vow, the mantra that would define his life:
Training Plan: 100 of everything. Every single day.
The clock on the wall of the shabby gym finally ticked past 5:00 PM. Kenzou, now sixteen, looked like a perfectly average high school student, maybe a little too serious. His brown hair, which had thinned drastically due to an inexplicable, persistent pattern of loss over the last year, was safely tucked beneath a faded, navy-blue baseball cap. He was lean, unassuming, and perpetually tired.
He quietly gathered his bag, ignoring the grunts and shouts of the other patrons, whose Quirks ranged from 'Minor Strength Enhancement' to 'Temporary Oxygen Deprivation.' Their training was always loud, always flashy. His was just... tedious.
He started his routine the moment he got home, fueled by a protein bar that tasted vaguely of cardboard.
100 Push-Ups.
100 Sit-Ups.
100 Squats.
A 10-Kilometer Run.
He performed them with perfect form, perfect control, and zero effort. His muscles never burned. His lungs never struggled. The training that should have turned an average man into a peak athlete had, instead, turned him into something far beyond that, completely without his knowledge.
To Kenzou, however, it was just the bare minimum.
Why don't I feel anything? he thought, his sweat-drenched hands gripping the asphalt during the last mile of his run. Deku-san nearly tore his arms off to reach his level. I must not be pushing myself hard enough.
This year, Kenzou had applied to every Hero school in the region, including U.A., the ultimate dream. And just like the last three years, he'd been rejected everywhere. The letters were always polite, the message identical: "Your physical exam scores were exceptional, however, all candidates must demonstrate the capability and control of a manifest Quirk for practical application."
The world still didn't believe in the Quirkless. They needed power. Kenzou had power beyond measure, but it was invisible to the scanners, intangible to the bureaucracy, and incomprehensible even to him.
Tonight, he ran the full 10 kilometers through the crowded evening streets of Musutafu. He was already doing his cooldown stretches in a small, empty park three minutes later, having run a pace that should have been physically impossible.
It was then that the ground shook.
Not a tremor, but a roaring, explosive impact that ripped through the quiet park. A plume of black smoke, tinged with purple energy, rose three blocks over. A Pro Hero alarm immediately began to wail, quickly followed by the panicked screams of civilians.
Kenzou didn't think; he reacted. The faded image of a determined, green-haired hero flashed through his mind. Heroes rush in.
He sprinted towards the commotion, weaving through the sudden chaos. He found the source: a gigantic man, easily ten meters tall, whose entire body was encased in black, shifting obsidian—a high-level, destructive villain known only as Giga-Rock. Giga-Rock was locked in a brutal battle with the local Pro Hero, Crush-Fist, a man whose Quirk allowed him to triple the density of his knuckles.
Crush-Fist was clearly losing. Giga-Rock roared, bringing a massive, diamond-hard fist down toward the already injured Pro.
"Move, you idiot!" Kenzou heard a nearby bystander scream.
But Giga-Rock's attack wasn't just aimed at the hero. A powerful side-sweep of debris, a half-ton chunk of shattered asphalt, was thrown directly at a terrified mother who had frozen, shielding her child by a demolished café.
Kenzou was closer. He didn't have a Quirk to enhance him, no power to activate. He just had the habit of 100 of everything. He launched himself forward, instinctively lifting his arm—not to punch, but just to shove the giant rock aside and clear the path.
He didn't use a named attack. He didn't power up. He just threw a desperate, untrained, casual, human punch at the speeding missile of asphalt.
The moment his fist made contact, the world went silent.
There was no sound of shattering rock. Instead, a clean, sharp crack echoed, followed immediately by a deafening sonic boom that blew out the remaining windows on the street. The half-ton slab of asphalt didn't break; it didn't deflect. It simply vaporized into a fine gray mist.
The force didn't stop there. The residual pressure wave, a clean, circular ripple of pure kinetic energy, continued outward. It slammed into the center of Giga-Rock's chest, who was still mid-strike against Crush-Fist.
The huge villain, a titan made of living stone, didn't stagger. He didn't fall. He simply flew.
Giga-Rock was launched skyward, not with the violence of a cannon, but with the terrifying speed of a runaway bullet. The monstrous obsidian form shrank instantly, disappearing over the horizon with a trail of purple smoke, leaving nothing behind but an unnerving silence.
Kenzou stood there, his arm extended, his fist clenched in the position he'd left it. His heart was hammering not from the exertion, but from the realization.
Did… did I do that?
He slowly turned his head to the mother and child, who were staring at him with a mixture of terror and utter confusion. Then he looked at the injured Crush-Fist, who was staring at the empty sky, mouth agape, completely forgetting the pain in his ribs.
Kenzou looked down at his right hand. It was fine. No swelling, no scratches, no pain. He had aimed to push a rock; he had accidentally sent a high-level villain into orbit with what felt like the effort of tossing a tennis ball.
"That… that can't be," Kenzou whispered, his mind racing. "I must have hit a weak spot. A fluke. It wasn't a Quirk... it was just a punch."
He didn't know he had the power of One-Punch. He just thought he was Quirkless.
His simple, earnest vow to become a hero had just put him on a collision course with a world that was entirely unprepared for him.
Kenzou's secret is out to the world (and to himself). What's the first thing he does when the first reporter runs up to him, and what does Crush-Fist say to the 'Quirkless' kid who just saved his life?