As a Grey Knight In Naruto

Chapter 68 – "Fire Beneath Flesh"

The air was calm in the Hokage Tower.

Sunlight poured through open windows, casting long, lazy beams across the polished floor. Shizune was at her usual corner, sorting supply ledgers with quiet focus. Tsunade leaned back in her chair with one foot on the desk and the other dangling, sipping tea as she stared blankly at a stack of ignored mission reports.

Hajime stood near the window, unreadable as always, flipping through a scroll with methodical ease. His presence, towering and quiet, had long since become part of the rhythm of the office. He didn't fidget. He didn't sigh. He simply worked.

"You're too efficient," Tsunade said without looking at him.

"You say that like it's a problem."

"It is. You make me look bad."

Shizune gave a small laugh but didn't look up. Hajime continued reviewing a new submission from the medical division.

Then the door opened and in came Sakura, cheeks flushed, hair damp, having just returned from the training grounds. She waved cheerfully. "Good morning!"

"Barely," Tsunade muttered.

"I brought fresh mochi," Sakura said, setting down a small box. "And the new injury reports from the outer field clinics."

Shizune brightened. "Oh, perfect."

Hajime accepted the documents from her with a nod. "Your form looked cleaner today. The elbow drop followed through properly."

"You were watching?" Sakura smiled.

"I always watch."

"That's kind of creepy."

"You said that yesterday too."

Sakura rolled her eyes. "Still is."

Tsunade waved a hand. "Alright, enough flirting. Go wash up, Sakura."

Sakura blinked. "That wasn't"

"She knows," Hajime interrupted, his voice dry.

Shizune snorted as Sakura groaned and left the room, mumbling something about tall weirdos and deadpan sarcasm.

Tsunade set down her cup and looked at him, more serious now. Her voice lowered slightly.

"Are you still planning to do it tonight?"

"Yes," Hajime said. "It's ready."

She glanced at him carefully. "You don't have to rush."

"I'm not," he said calmly. "But the longer I wait, the more I calculate failure probabilities. The conditions are optimal."

Tsunade sighed and leaned forward, resting her arms on her desk. "I still think you're insane. But if anyone can implant an experimental organ into themselves and walk it off like a twisted miracle, it's you."

He gave her a rare, small smile. "That's the highest praise I've received from you."

"Don't let it go to your oversized head."

.....

That night, Hajime walked out of the Hokage Tower Then walk To his underground lab entrance. He keyed in a silent psychic signature, and the mechanism rumbled open.

Below, deep in the sublevels beneath Konoha, was his private domain, an underground laboratory he had carved out himself using psychic manipulation and weeks of solitary construction. The walls were smooth, the floors clean, the air sterile and still. Light crystals embedded in the ceiling glowed faintly, cast faint shadows across workbenches stacked with scrolls, surgical tools, and nutrient chambers. At the center of the lab, suspended within a Containment Pod that preserves that are inside but time are not stopped, the completed Belisarian Furnace, a crimson biological mass, no larger than a clenched fist. Veined, compact, and still. The Belisarian Furnace. Or as Hajime had named it in his private notes: the Revitalizer.

Unlike the other organs he had implanted, this one was not designed for strength, speed, or enhancement. Its sole purpose was survival.

The Revitalizer was built to remain dormant, connected to both of Hajime's hearts through microvascular junctions. In the event of catastrophic trauma, massive blood loss, neural failure, systemic shock, it would activate. Upon activation, it would release a concentrated burst of synthesized regenerative compounds, stims, and stabilizers into his bloodstream, reinforcing his vitals, jump-starting his organs, and delaying death long enough to survive or escape.

Afterward, it would take time to rebuild its internal stores before it could trigger again.

Hajime sat on the surgical table and exhaled. With a single thought, the lights brightened.

He began the procedure.

No assistants. No chakra. No painkillers.

Only will.

With precise control, he severed the skin along his chest in a careful pattern by a psychic scalpel. Muscle parted cleanly. Blood vessels were sealed in real time as his psychic field manipulated each thread of tissue. He reached the ribcage, already enhanced by the Ossmodula implant, thicker, denser, and stronger than human norm.

He did not cut through them.

Instead, he parted them, bending the rib arcs open with invisible force until they unfolded like armored panels. The chest cavity, revealed beneath, thudded with quiet strength. Two hearts beat in unison, steady, powerful.

He guided the Revitalizer to the space between them.

There, behind the sternum and nested in protective tissues, he secured the gland. Threads extended, snaking into place, connecting to major arteries and neural signal lines. It pulsed once. Then again.

Alive.

He closed the chest, resetting the ribs with a heavy mental pull. They locked into place, overlapping in layers now, forming a natural armor, like a shield grown from his own body.

Then came muscle. Then skin. He sealed the final seam with nothing more than breath and thought.

The lab fell quiet.

Hajime stood slowly, placing a hand to the center of his chest.

Nothing felt different.

No burning. No power rush.

Only a stronger heart beat.

Later that night, the Hokage residence was quiet.

Shizune had gone to sleep. Sakura was curled up on the couch, unconscious under a blanket with her training manual still open on her chest. A single lamp cast a warm pool of light over the kitchen, where Tsunade stood at the sink, washing a cup in silence.

Hajime entered without a word, his shirt neatly buttoned.

Tsunade looked over her shoulder. "You did it?"

He nodded once.

She set the cup down and walked past him, pressing her palm lightly to his sternum. Her hand hovered, as if sensing something. But there was no chakra. No healing aura.

Only quiet warmth, faint beneath the skin.

She met his eyes. "Did it hurt?"

"No."

"Do you lie often?"

"Yes."

They stood in silence for a while, the soft hum of the fridge filling the room.

Tsunade sighed. "You've already gone far beyond human. You're still growing. Still changing. Don't lose sight of what you started this for."

"I haven't," he said quietly. "But I won't stop either."

"I know," she whispered.

She turned to leave, then paused and added without looking back, "Don't die, Hajime."

He watched her go, then looked out the window toward the star-filled sky. His hand drifted to his chest again.

It wasn't strength.

It wasn't power.

It was insurance.

And sometimes, that was enough.

End of Chapter 68 – "Fire Beneath Flesh"