As a Grey Knight In Naruto

Chapter 60 – "Primaris of the Grey Knights"

The lab was quiet again.

No whirring machinery. No buzzing lights. Only the silence of stone and thought. The lights were dim, powered by the chakra generator tucked away in the far wall, its steady pulse barely noticeable. Everything else was still.

Hajime stood in silence at the center of it all, breath calm, presence centered like the eye of a storm. Every tool was already prepared. Every rune etched in advance. Every contingency mapped. He had calculated all outcomes, examined them again and again, cross-referencing Grey Knight memory, Apothecary procedure, and the realities of chakra-based biology.

He opened his eyes slowly. The Sinew Coils floated within their containment pod, a reinforced stasis shell forged by hand, infused with Techmarine knowledge from the psychic echo of a fallen brother. It wasn't true stasis, like those used aboard battle barges, but it was close. Time couldn't be stopped, but it could be shaped. This pod slowed entropy, preserved structure, maintained the optimal biological state of its contents through sheer will. Every rune was engraved not with ink, but with telekinesis. Every latch sealed through psychic magnetism.

He reached forward.

A soft ripple passed through the lab as invisible force swept the air, pulsing once through every surface. It was psychic, pure and absolute. Not chakra. Not seals. With a twist of will, Hajime erased every microbe, every speck of dust, every trace of bacterial life from the air and stone. A field of sterilization that Grey Knight Apothecaries once used before battlefield implantation. The space was made clean.

He stepped forward.

Today would mark the implantation of the second Primaris organ: the Sinew Coils. It would push his body beyond shinobi limits, beyond anything a mere human should possess. Explosive strength. Resilient movement. Reaction speeds beyond what the eye could track.

But that strength came at a cost. Flashbacks rippled through his mind, Kimimaro's bone-laced body writhing under its own stress, Sakon and Ukon regenerating too fast, their cells twisting from imbalance. Even in the memories of the Apothecary Maladie, he recalled the Space Marines who were implanted with Sinew Coils only to damage themselves through their own strength, torn muscle, snapped joints, overstimulated nerve clusters.

Without containment, the organ would destabilize him. Not kill him. Not permanently. Hajime was beyond that now. He could use psychic healing to slow his blood loss, to restrain a shattered limb, to re-knit a tendon with mere thought. But it would still injure him. It would weaken him. And that was unacceptable.

Control was everything.

He was already outfitted in his new containment frame, the armorless scaffolding he forged with psychic-enhanced tools and chakra-reactive alloy. The spinal reinforcement tracked the curve of his back. Bracers clasped softly around his knees and elbows. His neck rested against the neural dampening collar, silver-blue, humming gently.

He lay himself back on the surgical stone slab, no restraints, no straps. None were needed.

With a flick of psychic command, his pain receptors shut down entirely. There was no numbing, no anesthetic. His body would still feel everything, but the pathways of agony were redirected, isolated. He could move. He could act. But the pain would not reach his mind.

This was the way he preferred it.

He lifted his right arm.

Telekinetic blades shimmered to life, invisible to the eye, but precise enough to split a cell. Slowly, calmly, Hajime began cutting into his own muscle. Along the forearms. Down the thighs. Across the spine. Surgical slits appeared, held open with directed fields of psychic pressure. Blood did not pool. It floated in gentle beads, pulled aside and preserved.

He floated the Sinew Coils from their pod.

Each tendril of living muscle-fiber glowed with an eerie sheen. Twisted together from White Zetsu tissue and chakra metal filaments, they were stronger than steel yet flexible as tendon. As the first strand touched open muscle, a resonance flared, a deep hum through his tissue. The Coils sought integration, bonding at once with his fibers like roots grafting into fertile earth.

With slow precision, he guided the Coils into place. Thread by thread, muscle by muscle. They wrapped through his forearms, binding flexor to tendon. They slid along his quadriceps, reinforcing every contraction. They aligned across his spine, fusing instinct with reaction. As he implanted them, chakra veins shimmered into visibility. His own life energy responded to the foreign material like a welcome guest, syncing instantly.

Halfway through the integration, his fingers twitched. His back arched. The spasms began.

The containment frame held.

Red flashes pulsed from the suppression cords along his limbs, instantly reacting to the violent surges. He felt the spasm, saw his arms twitch violently, but the reinforcement suppressed it all. The neural dampening collar bled subtle energy into his spine, muting the worst of the nerve lash.

But even without the frame, he would have survived. He was no ordinary being. With pure psychic power, he could have sealed torn muscle, halted a shattering bone, slowed his own heartbeat until the pain faded. He would not have died.

But he would have been crippled.

And Hajime didn't tolerate failure.

Then it happened:

A deep pull at his core.

The gene-seed responded.

It wasn't a voice. It was instinct, calculation, optimization. Hajime felt the implants shift within him, the Sinew Coils re-aligning themselves ever so slightly. As if the gene-seed understood his design. Understood his limits. And corrected them.

It was not mercy. It was improvement.

A moment passed.

The final coil pulsed.

Then silence.

When the reaction ended, Hajime sat up slowly.

He clenched his right fist.

Immediately, his knuckles cracked. The skin stretched tight over his fingers. The strength was too much, even restrained. Small fissures opened across his palm.

But he did not stop.

He stared.

This was what he had built.

Even if his bones broke, his punches would still land. The Sinew Coils weren't just additions, they were a second structure inside him, one that would keep moving even if flesh tore or bone snapped.

Like the ligature of a beast. Like the substructure of a siege weapon. The logic was undeniable: the Coils acted as redundant biomechanical engines, fusing kinetic persistence with anatomical brutality.

He stood.

Walked to the stone testing pillar near the edge of the lab.

Drew his fist back.

Punched.

The stone cratered inward. The crack echoed like thunder through the sealed lab.

And Hajime's arm remained steady.

He exhaled.

The suppression cords pulsed once, adapting to the output.

He looked down at his hands.

"I am," he said quietly, "the Primaris of the Grey Knights."

Not Astartes. Not Shinobi. Not relic, or relic-bearer. Not even student.

He was now something that even the Imperium refused to build.

And he had done it alone.

He turned toward the containment pod, now drained of purpose, and sealed it.

Tomorrow, he would leave this chamber.

But for now, he sat.

And let his heart beat through this new body.

End of Chapter 60 – "Primaris of the Grey Knights"