An Inexperienced "Jōnin"

In the late summer of Konoha's forty-sixth year, several months had passed since the complete fusion of his body. Uchiha Kyohaku's life had changed significantly. Using Orochimaru's influence and the excuse of "focusing on advanced medical research," he smoothly resigned from his position as an intern medical ninja at Konoha Hospital. From then on, his public identity vanished completely. He went fully underground, becoming Orochimaru's full-time laboratory assistant and immersing himself in an ocean of forbidden knowledge.

However, power without the ability to control it was like a tree without roots. Kyohaku understood this better than anyone. Possessing jōnin-level chakra, a healthy body, an evolved Sharingan, and the Mayfly Technique did not mean he could immediately become a qualified jōnin. He lacked the most crucial things: real combat experience and the instinct to integrate all his abilities into life-and-death battles.

So, beyond the laboratory, he devoted every remaining moment to almost brutal self-training. He chose Training Ground Forty-Four, also known as the Forest of Death, at the edge of the village and far from the crowds. With its complex terrain and roaming beasts, it was the perfect place for covert, high-intensity training.

At dawn or deep in the night, a pale figure would silently slip into the depths of the Forest of Death like a ghost.

He began adapting to this brand-new body. First came raw speed and strength. He sprinted at full speed through the gnarled trees, moving so fast he nearly left afterimages behind. His powerful legs erupted with astonishing jumping force, allowing him to race up vertical trunks and reach the canopy with ease. Every terrain obstacle that had once troubled him now felt like flat ground.

Bolstered by the Sharingan, his dynamic vision and neural reaction speed became terrifying. He stood in a forest clearing and let startled flocks of birds burst into flight. The tomoe in his pupils spun rapidly as he clearly captured, analyzed, and predicted the flight path of every bird, every falling leaf, even the tiny motes of dust kicked up in the air. He threw dozens of shuriken at once, each one precisely grazing a bird's wingtip or piercing a chosen falling leaf. Not a single one missed.

He trained the basic Three-Body Technique to the utmost limit. His clones were no longer illusory images, but highly realistic doubles capable of causing a degree of physical interference. His Substitution Technique timing was incredibly tricky, often completing the switch at the very instant an attack was about to strike. The log left behind could even simulate the effects of being hit through residual chakra. His Transformation Technique could instantly mimic the surrounding environment, achieving an effect close to optical camouflage.

His Fire Style ninjutsu was no longer limited to the Great Fireball and Phoenix Flower Fire his father had left him. Through Orochimaru's collection of books, he learned more B-rank and even A-rank Fire Style techniques, such as the more concentrated Fire Dragon Flame Bullet and the wider-ranging Ash Pile Burning. His immense chakra supported repeated practice until every hand seal became muscle memory and every chakra nature transformation came at his command.

Thanks to the Earth affinity granted by White Zetsu cells, he even began exploring Earth Style. Though he was far less proficient with it than Fire Style, he could already skillfully use several basic techniques, including Earth-Style Wall and Earth-Style: Headhunter Jutsu, further expanding his tactical options.

Sharingan genjutsu became a weapon he focused on honing. He did not need complex visual guidance. Sometimes, a mere meeting of gazes, combined with his powerful spiritual energy, was enough to leave a charging beast in the forest stunned or confused. He continually experimented with combining genjutsu and the Body Flicker Technique to create visual deception and launch silent ambushes.

Speaking of the Body Flicker Technique, it was one of the core focuses of his training. Combined with the newly acquired Mayfly Technique, which allowed him to travel through the earth, his movements became strange and unpredictable. At times, he flickered through the forest at high speed, leaving afterimage after afterimage behind. At others, he instantly sank underground and silently emerged from a completely unexpected direction to launch a fatal blow. His use of the Body Flicker Technique had begun to take on something of a ghostly quality.

Day after day, the deep silence of the Forest of Death echoed with the explosions of ninjutsu, the whistling flight of shuriken, and the wind stirred by his rapidly moving body. Tirelessly, he tempered himself, breaking down, combining, and optimizing every ability as he tried to forge them into an efficient and deadly combat system of his own.

He was like a race car driver with a top-tier engine and chassis who had only just gotten his license. He needed frenzied practice to master that power.

Naturally, none of this escaped Orochimaru's notice. From time to time, he would quietly appear at the edge of the training ground, watching Kyohaku's progress like a hidden venomous snake.

"Good firepower, but the chakra flow through the third branch of your meridians could be smoother. That would reduce your hand seal time by 0.3 seconds." His hoarse voice would suddenly emerge from the shadows, pointing out subtle flaws Kyohaku himself had never noticed.

Or, "Your genjutsu relies too heavily on vision. Try transmitting chakra through sound or environmental vibrations. It will cover a wider area."

Orochimaru's guidance was always precise and incisive, striking directly at the heart of the problem. He was happy to watch Kyohaku grow. It proved that his investment, whether in knowledge or resources, was yielding generous returns.

After several months of high-intensity training, Uchiha Kyohaku's strength had undergone a complete transformation. He truly possessed genuine jōnin-level chakra, physical abilities far beyond those of ordinary jōnin thanks to the strengthening of White Zetsu cells, an evolved Sharingan, proficient mastery of multi-element ninjutsu, and strange movement techniques.

Yet he was still a "jōnin" who had never truly carried out a ninja mission, experienced a life-and-death battle, or been tempered on a battlefield. His combat style still bore an obvious laboratory flavor—precise, efficient, and always seeking the optimal solution, yet lacking the savagery, instinct, and adaptability honed through blood and fire.

He was a carefully forged, incomparably sharp sword that had yet to truly taste blood.

Standing at the center of the Forest of Death, Kyohaku slowly calmed the chakra surging through his body. His pale skin looked even more eerie beneath the moonlight. His nearly three-tomoe Sharingan swept over the wrecked surroundings he had destroyed through training, calmly assessing his progress and shortcomings.

The power was already there. What he needed next was a true... battlefield on which to test his blade.