The sun hung low over the Hidden Leaf Village, casting long, distorted shadows across the training grounds of the Uchiha District. To any passerby, the boy standing in Training Ground 13 looked entirely unremarkable. Dan Uchiha, age five, possessed the standard raven-black hair of his kin, though he wore it shorter, and his dark eyes lacked the piercing intensity found in the "true geniuses" of the clan.
In a generation defined by the meteoric rise of Kakashi Hatake—the boy who had graduated the Academy at age five and was already being sized up for Chunin promotion—Dan was a ghost. He was the "filler" in the classroom, the one whose grades were high enough to avoid scolding but low enough to avoid scrutiny.
But inside Dan's mind, a storm was raging.
Focus, Dan, he told himself, wiping sweat from his brow. Three minutes until the next synchronization.
Deep within his consciousness sat the Eternal Mirror Space. It was a void of shimmering silver light where a spectral version of himself—the System Clone—stood just like it did for the past 3 months. This clone did not feel pain. It did not feel boredom. It did not require sleep. Since the moment Dan had "awakened" in this world with the memories of a past life and this mysterious system, the clone had been training.
While Dan sat through boring lectures on the history of the Will of Fire, the clone was practicing the Academy Three: Substitution, Transformation, and Clone Jutsu. While Dan slept, the clone was performing grueling sets of calisthenics.
[System Notification: 6-Hour Cycle Complete. Synchronizing Physical Prowess...]
A sudden, sharp heat flared in Dan's bone marrow. It felt as though his blood had been replaced with molten lead for a fraction of a second. His muscles twitched, expanding and contracting with violent speed as the "gains" from the clone's six hours of high-intensity explosive training were written into his physical DNA.
He gasped, gripping his knees. When he looked down at his hands, they looked the same, but he felt… denser. More anchored to the earth.
"Again," Dan whispered.
He reached into his holster and pulled out a standard-issue kunai. He stood thirty paces from a wooden post. He didn't just throw it; he recalled the "muscle memory" his clone had just spent six hours perfecting—the exact angle of the wrist, the release point of the fingers, the weight distribution in the lead foot.
Thack.
The kunai buried itself dead center in the bullseye. It didn't just stick; it hit with such force that the wood groaned and cracked.
"Not bad for a 'mediocre' Uchiha," a voice drawled from the shadows of the treeline.
Dan didn't jump. His heightened senses, a gift from the constant synchronization, had picked up the scent of ozone and the light tread of sandals moments ago. He turned to see a boy his own age with silver, gravity-defying hair and a mask covering the lower half of his face.
Kakashi Hatake.
"Kakashi," Dan said neutrally. "Shouldn't you be out on a mission? I heard you were too busy for the training grounds these days."
Kakashi stepped into the light, his lone visible eye narrowed in appraisal. He looked at the kunai buried in the post, then back at Dan. "I was passing by. Your form... it's strange."
"Strange how?"
"It's too perfect," Kakashi said, his voice devoid of emotion but laced with a hint of genuine curiosity. "You haven't been in the top of the class for throwing. Yet, that throw had the weight of someone who has practiced for twenty years. How many times did you practice that today, Dan?"
In this body? Once, Dan thought. In the system? Ten thousand times.
"I just got lucky," Dan lied easily.
"Luck doesn't crack seasoned timber," Kakashi countered. He walked over to the post, gripped the handle of the kunai, and pulled. He had to use a surprising amount of strength to dislodge it. "The war is coming, Dan. The teachers are talking about early graduations for everyone, not just the 'geniuses.' If you're hiding your strength, you're an idiot. In a war, strength is the only thing that keeps you from being a name on a stone."
"I'll keep that in mind," Dan said, picking up another kunai.
Kakashi lingered for a moment, as if waiting for a challenge, but when Dan didn't offer one, the silver-haired prodigy vanished in a blur of speed—a rudimentary Body Flicker.
Dan watched the space where Kakashi had been. He's fast. Naturally fast. But he's human. He has to rest. He has to eat. My clone doesn't.
He closed his eyes and entered the Mirror Space for a moment. He saw his spectral self now standing in a combat stance.
"System," Dan commanded mentally. "The clone has mastered the basic kunai trajectory. Shift training priority. 60% of output to Chakra Control: Leaf Concentration, 40% to Uchiha Interceptor Taijutsu."
The spectral clone immediately shifted. It began to move with a fluidity that was almost haunting, punching and kicking an invisible opponent.
Dan left the training ground and began the walk back to the Uchiha compound. As he walked, he passed the grand gates where the Uchiha Crest—the uchiwa fan—was proudly displayed. He saw the older shinobi, the ones with the red glint of the Sharingan in their eyes, looking down at the children with expectations of greatness.
He hated it. The Uchiha were a powder keg, and the Third Shinobi World War was the match. If he stayed "average," he'd be sent to the front lines as cannon fodder. If he became a "prodigy" like Kakashi, he'd be targeted by every Iwa and Kumo assassin looking for a trophy.
He needed a third path: The Shadow.
When he reached his small, Spartan apartment, he sat on the floor and pulled out a tattered scroll he'd "borrowed" from the Academy's restricted section. It was the theory of the Body Flicker Jutsu (Shunshin).
To a normal five-year-old, the chakra circulatory theory was a nightmare of complex symbols and spiritual energy ratios. But Dan didn't need to master it tonight. He just needed to understand the logic.
He read for three hours, tracing the diagrams of the leg muscles and the specific gates the chakra needed to burst through. As the clock struck midnight, a chime rang in his head.
[New Skill Detected: Shunshin no Jutsu (Theory Level).]
[Would you like the Eternal Clone to begin physical execution?]
Yes, Dan thought, a cold smile touching his lips.
As Dan crawled into his bed and drifted into a peaceful sleep, his clone began to move. In the Mirror Space, the specter began to flicker. It failed. It crashed. It strained its spectral muscles. But it didn't stop.
While the rest of the world slept, while Kakashi Hatake recovered his strength, and while the Great Nations sharpened their kunai for war, Dan Uchiha was training.
By the time the sun rose, Dan would have practiced the Body Flicker three thousand times. His muscles would be imbued with the memory of the speed, and his chakra pathways would be conditioned to the strain.
He was the only person in the world who could get stronger while he slept. And in a world of ninjas, that wasn't just an advantage—it was a godhood in the making.