It was a success.
Although not yet refined through thorough testing, the prototype worked—at least on the surface.
Uchiha Kai's emotions whiplashed like a kunai in a storm.
It felt like his lungs had forgotten how to breathe, his chest compressed under the weight of revelation.
So this is what Fan Jin felt... Kai remembered the old tale of a scholar driven mad by sudden success. He scoffed at the thought, then exhaled slowly.
Before him, the prototype vessel shimmered faintly under the sterile light. It was stable—for now.
"Can this be used for a dermal compatibility test?" Kai asked, keeping his voice level.
Hyūga Aya paused mid-adjustment of the equipment, her Byakugan flaring slightly as she considered.
"A skin test? For chakra rejection or allergic response?" she asked. "There's no precedent for that in chakra transplantation protocols. We typically only run blood-type compatibility and host rejection simulations—but I can attempt one."
"Then run it," Kai ordered. "As long as the risk is minimal."
Aya gave a small nod, retrieving a sterilized syringe. Despite the novelty of the procedure, she didn't hesitate. Even if the science behind this was uncharted, her medical training held steady.
She extracted a small sample of processed serum, disinfected Kai's forearm, and began the intradermal injection.
"I hope this works," she murmured. "Otherwise, we'll need a full chakra resonance assay."
Aya glanced around the lab, her Byakugan briefly scanning the area. "Also… you might want to have someone sweep this place. The flies are unusually active today."
"Flies?" Kai blinked, then frowned. "Wait… How did we dispose of Uchiha Osamu's body?"
"It wasn't me. The cleanup squad handled it. I believe it was incinerated per protocol," Aya replied, barely hiding her tension.
Kai's Sharingan whirled to life briefly. "And you're certain no one discovered the site today?"
Aya turned her head slightly, activating her dōjutsu again. "East. Roughly a kilometer. One chakra signature. Not suppressing their presence entirely… likely a scout. Could be a Yoru clan member."
Kai stood. His tone sharpened. "How long ago?"
"About twenty minutes."
"Sterilize everything. Prep for a purge if needed. I'll be back in twenty."
Yoru Ryōma was among the Root's most loyal agents.
Unlike many who were conscripted into Danzō's underworld, Ryōma had volunteered—drawn in by its ideology. Danzō wasn't just a leader to him. He was a doctrine.
He regretted not being part of the mission to the Land of Rain—the one where all but Danzō perished. That loss only solidified Ryōma's belief: if anyone could survive such odds, it was Danzō-sama.
Now, his mission was clear: observe and report on Uchiha Kai.
The boy had risen too far, too fast—appointed Captain of the Konoha Military Police at a young age. To Root, that could only mean one thing: a puppet of Uchiha Fugaku.
But after several days of surveillance, Ryōma began to doubt that assumption.
This boy isn't a puppet.
He's the hand pulling the strings.
The entire department bent to Kai's will. Patrol rotations, interrogation procedures, diplomatic reports with ANBU—all flowed through him.
Worse, Ryōma had traced his movements beyond the district walls… into the forests east of the village. There, hidden by fūinjutsu and sensor jamming techniques, was a subterranean facility.
A lab.
Ryōma couldn't breach it—at least not without alerting every seal in a hundred meters. But flies? Flies were disposable.
He'd deployed a mixture of minute, chakra-coated beetles and unremarkable insects—flies, gnats, even larvae. No ninja gave flies a second glance.
The gamble paid off.
What the bugs reported chilled him. A full-scale underground lab. Chakra containment units. A sample of Uchiha Osamu—long thought dead.
And something more dangerous: Kai was experimenting. On what, Ryōma couldn't say, but the word "cellular recombination" kept coming up. Bloodline transference? Cloning? Genetic weaponization?
He didn't need the full picture. This was enough to indict the boy.
Ryōma scrawled a coded report, activating a sealing tag to mask the ink from prying eyes. As he prepared to summon his carrier hawk, his instinct flared.
Danger.
In a single, fluid motion, he blurred through hand seals and Body Flickered to a nearby tree branch—
—just as a crackling blade of lightning split the air where he had been.
The insects that had formed his clone burned into smoldering ash.
His heart clenched. There were only two shinobi in the village with that kind of lightning-charged kenjutsu.
Hatake Kakashi.
And Uchiha Kai.
He turned slowly—and saw the figure step from the shadows.
Black flak vest. Crimson Sharingan. A blade humming with lightning.
"ANBU?" Ryōma hissed. "Or is this personal?"
Kai didn't answer right away. He studied Ryōma as though weighing a specimen.
"The Yoru clan," he finally said. "Danzō sent you, didn't he?"
Ryōma said nothing. In Root, silence was doctrine.
But he didn't flee. He summoned his swarm—beetles and hornets and chakra-enhanced flies poured from his sleeves and collar.
This was war.
Root agents do not fail, he reminded himself. They die completing the mission.
Kai exhaled softly, his expression unreadable.
"It's funny," he said, his voice low. "You all thought I was Fugaku's pawn. But pawns don't build weapons like this."
His eyes bled into Mangekyō Sharingan—jagged triangles spinning into focus. Chakra surged around him, dark and suffocating.
The forest trembled.
A ribcage of spectral bones emerged from his frame, rapidly forming limbs and muscle. Within seconds, a fully armored Susanoo stood towering behind him—eyes burning red.
In its right hand, a massive obsidian blade pulsed with killing intent.
"You wanted to know my secret, Yoru Ryōma?" Kai said, voice echoing with power. "Congratulations."
"You're the first to see this and live long enough to understand it."