The recovery from the "Overdrive" felt like waking up inside a furnace that had long since cooled to a dull, aching grey. Kaito lay on a medical cot back at the forward operating base, the rhythmic drumming of the Rain country's tears against the canvas tent providing the only soundtrack to his thoughts. His lungs felt brittle, as if every breath were pulling at a web of fine glass needles woven into his chest.
Beside him, resting on a wooden crate, was the reward from the System's last gamble: [Slaughter Demon (Fragment)]. It wasn't the full weapon he remembered from the tales of Jujutsu sorcerers, but a jagged, obsidian-hued blade that seemed to swallow the dim light of the medical seals. It hummed with a low-frequency vibration that resonated with his own Total Concentration Breathing.
> [System Status: Integration Level 2.0%]
> Weapon Synchronized: [Slaughter Demon (Fragment)]
> Trait: Cursed Energy Conductivity — The blade ignores 10% of standard Chakra-based defenses.
>
The tent flap shifted. It wasn't Tsunade's warm medical glow or Kagami's sharp, Uchiha presence that entered. It was a man wrapped in shadows, his face partially obscured by bandages, his one visible eye as cold as a mountain lake.
Danzo Shimura.
The leader of the Foundation didn't speak immediately. He stood over Kaito's cot, his gaze dissecting the boy not as a child, but as a potential asset.
"The report on the 'Black Flash' reached my desk yesterday," Danzo said, his voice a dry rasp that sounded like sandpaper on bone. "A civilian child with no bloodline, shattering the iron-plating of a Jonin's summon. Hiruzen thinks you are a miracle of the Leaf. I know better."
Kaito sat up slowly, his ribs groaning in protest. He flared his Observation Haki, but Danzo's intent was a void—a practiced, artificial nothingness. "What do you want, Shimura-sama?"
"I want the Leaf to survive this war," Danzo countered. "The Sannin are being groomed as the village's public heroes. They are the sun. But the sun needs a shadow to define it. You, Kaito, have a body that leaves no chakra signature. You move between the gaps of sensory nets. You are a 'Hollow' that the Rain cannot track."
Danzo leaned in, his shadow eclipsing Kaito. "There is a laboratory three miles into the heart of the Pipe Forest. They are developing a biological toxin that will turn the Land of Fire's forests into a graveyard. I want you to go in, retrieve the data, and ensure that the scientists never wake up."
> [Main Quest: The Root's First Harvest]
> Objective: Infiltrate the Hidden Rain Bio-Lab.
> Condition: Zero Chakra usage (Must rely on Physical/System abilities).
> Reward: [One Piece - Soru (Refined)] or [JJK - Cursed Tool: Playful Cloud (Initial Rank)].
>
The Silent Descent
Six hours later, Kaito was moving through the rain again. He didn't have Kagami or the Sannin with him this time. This was a "Shadow Mission," a task for the boy who officially didn't exist in the village's rosters.
He clutched Slaughter Demon in his right hand. The blade felt like an extension of his own nervous system. Every time he took a Total Concentration breath, the obsidian metal pulsed with a faint, violet light.
The lab was hidden inside a massive, vertical exhaust pipe, disguised as a rusted ventilation shaft. Kaito reached the entrance, his feet silent as he used the initial principles of Kamie to sway with the wind, making his physical presence indistinguishable from the swaying pipe-work.
He didn't use a lockpick. He focused his Armament Haki into the tip of his new blade.
Harden.
The obsidian edge turned a deeper shade of void. He slid the blade into the iron door's seam and pulled. The metal didn't groan; it parted like butter.
The Laboratory of Horrors
Inside, the air was sterile and cold. Glass vats filled with a glowing, purple liquid lined the walls. Inside the vats, Kaito saw things that made his hyper-oxygenated blood run cold: human lungs, preserved and pulsating with a viral growth, being "fed" chakra through a series of tubes.
"Who's there?" a voice barked from the central console.
Three Rain medical-nin, specialized in toxicology, stood up. They weren't front-line fighters, but they were Chunin-level threats with poison-coated scalpels.
"A child?" one of them gasped. "How did he get past the sensors?"
"He has no chakra," another realized, reaching for an alarm.
Kaito didn't give them the chance.
[Soru - Prototype]
He disappeared. He appeared in the center of the trio before the alarm could even ring. He swung Slaughter Demon in a wide, horizontal arc.
The blade ignored their chakra-reinforced vests. It cut through the fabric and the flesh beneath with a terrifying, silent hunger. Two of the ninjas collapsed instantly, their wounds not bleeding but looking "seared" by the cursed energy fragment within the blade.
The third ninja managed to draw a kunai, but Kaito didn't dodge. He caught the blade with his bare left hand, his Armament Haki turning his skin into obsidian.
THUD.
The kunai snapped against his palm. Kaito drove the pommel of his dagger into the man's throat.
Silence.
The Decision of the Anomaly
Kaito reached the central console and downloaded the data onto a scroll Danzo had provided. He then looked at the vats of viral toxins. He could leave now. He could be the perfect tool Danzo wanted.
But the Observation Haki was screaming. Not about enemies, but about the wrongness of the place. He felt the "intent" of the dying lungs in the vats—a silent, agonizing plea for an end.
"I'm not a root," Kaito whispered to the empty room. "And I'm not a hero."
He took a massive breath.
"Total Concentration... Burst!"
He slammed his Haki-coated fist into the central cooling unit of the lab. At the same time, he channeled his Divergent Fist logic into the obsidian blade, plunging it into the main viral reservoir.
BOOM.
The delayed impact of the Divergent Fist combined with the volatile nature of the Cursed Tool created a chain reaction. The lab began to rumble as the pipes started to collapse inward.
> [Quest Update: Escape the Collapse]
> Current Integration Jump: 2.0% -> 2.5%
>
Kaito sprinted back toward the exhaust shaft. As the lab behind him turned into a graveyard of twisted metal and steam, he felt the System hum with a new, dark satisfaction.
The Return to the Light
Kaito emerged from the Pipe Forest just as the sun—a pale, sickly imitation of light—tried to pierce the Rain's clouds. He found the Sannin waiting for him at the edge of the perimeter.
Tsunade ran forward, her face a mix of fury and relief. "Where were you? We searched the whole camp! Kagami-sensei was about to call back the entire patrol!"
Kaito looked at her, his eyes hollow. He tucked the obsidian blade into his inventory, the movement so fluid it looked like magic. "I went for a walk, Tsunade-san. I needed to breathe."
Orochimaru stepped up, his yellow eyes narrowing as he caught the faint scent of sterile chemicals and ozone clinging to Kaito's vest. He looked toward the smoke rising from the Pipe Forest in the distance.
"A very productive walk, Kaito-kun," Orochimaru whispered, a thin smile touching his lips. "It seems the shadow is growing faster than the sun."
Kaito didn't answer. He just kept breathing.
> [Quest Complete: The Root's First Harvest]
> Reward Unlocked: [One Piece - Soru (Refined)]
> Integration Progress: 2.5%
> New Item in Shop: [Jujutsu Kaisen - Cursed Tool: Playful Cloud].
>