This story is a fanfiction inspired by My Hero Academia (Boku no Hero Academia) created by Kōhei Horikoshi, and Ninjago created by LEGO.
All original characters, settings, and concepts from these franchises belong to their respective creators and copyright holders.
Chapter 1: The Dojo in the Valley
The world had become loud.
In the sprawling, neon-drenched cities of Japan, the air thrummed with the constant, chaotic energy of Quirks. Heroes in colorful, stylized costumes leaped between skyscrapers, their battles and victories broadcast on towering digital screens. The news cycle was a blur of power levels, debut rankings, and collateral damage. Society had reshaped itself around the extraordinary, leaving little room for the quiet, the simple, or the old.
But far from that noise, nestled deep within the Kii Peninsula, lay a valley shrouded in mist and silence. Here, the only screens were the serene surfaces of koi ponds, and the only broadcasts were the songs of the uguisu, the bush warbler, flitting through dense bamboo groves.
The air smelled of damp earth, crushed pine needles, and the faint, sweet perfume of wild azaleas. Ancient cedar trees, their trunks as wide as carriages, formed a silent wall against the outside world. Through this green cathedral, a river rushed, its water so clear and cold it seemed to steal the blue from the sky. Herds of sika deer drank from its banks, their ears twitching at the snap of a twig, their dark eyes reflecting a world without heroes or villains—only the forest.
And deep within that forest, hidden from satellite and map alike, stood a simple, wooden dojo.
It was old, the dark cedar planks worn smooth by countless seasons. It stood on stilts over a carpet of moss-covered rocks. From the outside, it was just another part of the silent landscape. But today, it was not silent.
THWACK. FWOOM. HIII-YA!
The sharp sounds of combat, of impact and exertion, echoed from within, disturbing the peaceful squirrels gathering acorns on the roof.
Inside, the world was one of structured shadow and light. The afternoon sun filtered through shoji screens, painting golden rectangles on the polished dark-wood floor. The air smelled of old wood, focused sweat, and the faint, calming trace of sandalwood incense. The walls were bare, save for a few hanging scrolls depicting simple, single-stroke calligraphy.
At the far end of the room sat Sensei Wu.
He was a portrait of stillness in a room of motion. He sat in seiza, his back perfectly straight. A long, impossAssibly white beard flowed from his chin, brushing the tatami mat beneath him. He wore simple white robes, and his conical kasa hat lay beside him. His eyes, nested in a web of ancient wrinkles, were sharp and missed nothing. His aged hands, knuckles like old roots, were clasped behind his back, his simple oak staff resting against his shoulder.
He watched, his gaze unwavering, as two blurs of color collided in the center of the room.
"No, Jay," Wu's voice was not loud, but it cut through the sounds of the fight. "Your footwork is unbalanced. You are anticipating the strike, not reacting to it. You are fighting where you think he will be, not where he is."
The blue blur, Jay, flipped backward, landing lightly. He wore a blue training gi, his auburn hair plastered to his forehead with sweat. His bright, crackling eyes narrowed. "Easy for you to say, Sensei! Have you seen him?"
His opponent, the red blur, didn't wait. Kai lunged. He was all aggression and power, his spiky brown hair defying gravity, his amber eyes burning with focus. His red gi was already dark with exertion.
This was not a Quirk brawl. It was pure Taijutsu—high-level, disciplined martial arts. It was a dance of block, parry, strike, and sweep, executed at a speed that would baffle any city-dwelling hero. Jay was faster, a hummingbird of feints and dodges, his mocking laughter echoing as he tapped Kai's shoulder.
"Too slow! Too slow! You're fightin' like a grumpy badger!" Jay taunted, ducking under a wide, powerful hook kick.
"Stand still and fight me, you coward!" Kai roared, his frustration mounting with every missed blow.
Kneeling perfectly still on the sidelines, two other students watched. One, dressed in a black gi, was built like a young bull. His dark hair was shorn short, and his arms, thick with muscle, were crossed over his chest. This was Cole, the anchor, his face a mask of calm focus.
Beside him, in a white gi, sat Zane. His pale blond hair was cut in a severe, logical flat-top. His icy blue eyes did not blink. He was unnervingly still, his head tilting slightly as he analyzed every movement, calculating trajectories and reaction times.
Jay, feeling cocky, saw an opening. He zipped in, evading Kai's guard, and tapped him lightly on the nose. "Boop!"
Something in Kai snapped.
This… this jokester! Kai's internal monologue was a roar. He's not taking this seriously! He never takes anything seriously!
The disciplined control Wu had drilled into him for years evaporated. It wasn't a decision; it was a release.
"RAAAGH!"
Kai's right fist ignited. The air in the dojo shimmered. The smell of ozone and sulfur stung the air as orange flames, bright and angry, enveloped his hand.
Jay's playful expression vanished, replaced by pure panic. "Hey! No Quirks! Wu said no Quirks this session!"
He threw his hands up instinctively. In his fear, his own Quirk responded. Chaotic blue sparks, crackling with panicked energy, leaped between his fingers, hissing like angry snakes.
Kai didn't, or couldn't, stop. He thrust his flaming fist forward. FWOOSH! A ball of fire, jagged and uncontrolled, shot across the room.
Jay yelped and threw up a desperate shield of static.
KRAK-BOOOOM!
The elements collided. The resulting explosion was small but violent, a concussive blast of superheated air and static. The shockwave rattled the shoji screens in their frames and sent a small vase of flowers toppling over.
Jay was blown backward, skidding across the tatami mats like a stone on water before slamming hard into the far wall. He slumped to the ground, a cloud of smoke and the smell of singed hair rising from him.
Silence.
Kai stood panting, his fist still smoking. His eyes were wide. "Oops... Sorry, Jay. It just… it happened. Instinct."
Sensei Wu did not shout. He did not move. He simply set down the teacup he hadn't been holding, and with a slow, deliberate motion, pinched the bridge of his nose. A deep, pained sigh escaped him.
From the floor, Jay pushed himself up, rubbing the back of his head. A black smudge of soot covered his cheek. "Are you crazy?" he coughed, waving smoke from his face. "'Instinct'? That was on purpose! You could've fried me!"
Kai's defensiveness flared as fast as his fist had. "You know I wouldn't do that intentionally! You were… you were mocking me! You weren't taking it seriously!"
"Mocking you?! It's called sparring, sparky! You just can't control yourself!" Jay shot back, getting to his feet. "How can you be so reckless with your Quirk? We're indoors!"
"Oh, like you're one to talk, Mr. 'Let's-See-If-I-Can-Short-Out-The-Rice-Cooker-Again'!"
"That was an experiment!"
From the sidelines, Cole let out a low groan, his voice deep and tired. "And... here we go again."
Zane tilted his head. "Their bickering frequency has increased by 15.4 percent this week. It appears to be cyclical."
The shoji door to the main house slid open, the sound cutting through the argument. Nya stood there, her dark hair tied back, a practical apron over her clothes. She held a simple wooden tray. The delicate, sweet scent of jasmine tea wafted into the room, cutting through the smell of ozone and smoke.
She smiled wryly, her gaze landing on the singed spot on the wall and the two fuming boys. "Are they arguing again? Must be Tuesday."
Cole and Zane stood, bowing their heads slightly. "Thank you, Nya," Zane said, his voice a calm monotone. Cole just grunted his appreciation, taking a cup and gratefully sipping the warm liquid.
Nya walked directly between Kai and Jay, who were still glaring at each other. "Honestly, you two," she said, her voice laced with fond exasperation. "Kai, you're fire. Jay, you're lightning. Your elemental natures don't really match. I can't exactly tell you to get along."
She held out the tray. "But," she added, her smile softening, "everything can be fixed with a tea break. What do you say?"
Kai grumbled, breaking eye contact first. "Fine." He took a cup.
Jay huffed. "Yeah, yeah. A break sounds good." He snatched his, wincing as his sore muscles protested.
The tension broke. Cole pointed at Jay's head. "Your hair... it's sticking straight up. More than usual."
Jay felt it, and his eyes widened. "Agh! I look ridiculous!"
Kai snorted, a laugh escaping him. "It's an improvement."
The dojo filled with the sounds of hesitant laughter and the clinking of ceramic cups. Even Wu allowed a small, faint smile to touch his lips. He was about to speak, to turn this into a lesson on control, when a new sound pierced the air.
SKREEE!
It was a sharp, clear cry. Not a local bird.
The students quieted. Wu stood, his movements fluid and silent. He slid open the large engi (veranda) door and stepped out into the cool evening air.
A large, majestic falcon, its feathers a mix of brown and white, circled the dojo once. It was not a drone, not a machine, but a living creature. It swooped down, landing with impossible gentleness on Wu's outstretched forearm, its talons barely grazing the thick leather bracer he always wore.
A small, tightly rolled scroll was tied to its leg with a red ribbon.
The four ninja and Nya watched from the doorway. Wu untied the scroll. He unrolled it. As his eyes scanned the neat, precise lines of ink, his usually serene expression tightened. The faint smile vanished.
He murmured, his voice so low it was almost lost to the wind rustling the bamboo.
"Hero Society... again. It truly has been a long time..."