As a Grey Knight In Naruto

Chapter 34 – Bones of Growth

The midday sun hung high over Tanzaku Quarters, casting lazy beams through the open clinic window. The air inside buzzed with calm activity, herbal smoke curling from a nearby burner, the clatter of glass vials and ceramic trays. Hajime stood behind the counter, carefully bandaging a merchant's sprained wrist while Shizune sorted powdered salves at the shelf nearby.

"You'll need to rest it for a week," Hajime said softly, his chakra-infused hands finishing the wrap with a firm but gentle knot. "No lifting crates, no arm-wrestling, and no, what was it, trying to climb your own cart again."

The merchant chuckled nervously. "You heard that?"

"I heard your shoulder pop from the street."

After a few parting words, the man left with a grateful nod. Hajime turned toward the storage room and quietly stepped out through the side door. It was time.

Behind the clinic, in the shaded alley where few ever walked, he drew his cloak tight and exited into the market. His steps were quiet, his mind focused.

The next organ would change everything.

The Ossmodula. In Astartes transformation, it was one of the most crucial augmentations, a gland that secreted chemical agents and growth hormones, targeting skeletal density and length. When activated, it would stimulate massive bone growth across the body, mandibles, ribs, spine, even the skull, all designed to reinforce and restructure the human frame into something beyond.

But to do so, it required calcium. An impossible amount of it.

Hajime walked through the open-air stalls of Tanzaku's merchant district, hood low, head bowed, hands slipping coins into palms.

He bought cartloads of dried anchovies, powdered bones, fish heads, animal marrow, shell fragments. From the butcher, he bought entire baskets of cleaned animal bones, many hollowed and dried, others cracked for marrow. The stall owner gave him a strange look as he walked away with sacks of bone powder and raw femurs.

From a traveling herbalist, he secured mineral salts and seaweed flakes, rich in iodine and trace nutrients to balance the calcium absorption. He gathered it all like a monk gathering prayer beads, quietly and with purpose.

When his arms were full, he returned to the clinic through the side entrance.

Tsunade was seated inside, reclining near the doorway with a bottle of sake in hand and one eye half-lidded in amused curiosity. She took one look at him and frowned. "Brat," she said, "Why are you carrying a mountain of bones like some grave robber?"

Hajime blinked. "They're for food."

Her eyebrow twitched. "Bones are food now?"

"I've been feeling like I'm going to grow a lot soon. Like, a lot. So, calcium."

Shizune nearly dropped a jar behind him. "That's… not how growth spurts work."

"I'm built different," Hajime said calmly, his technically not lying, he'll indeed go to a massive growth spurt.

Tsunade stared for a long moment, glass held just beneath her lips. She narrowed her eyes. "One of these days, I'm going to dissect your brain, brat."

"I'd advise against it," Hajime replied without missing a beat. "It's a bit… layered."

He disappeared into the back room without another word, leaving Tsunade frowning after him.

That night, when the clinic had fallen into silence and the lanterns outside flickered low, Hajime slipped out again, this time with all the materials packed into scrolls sealed in ink.

The moon guided him deep into the forest, far beyond the reach of foot traffic, until the terrain dipped into rocky hollows and ancient roots. He knelt beside the forest floor, placed one hand on the soil, and opened the hidden passage.

The ground shifted silently, parting beneath him.

He descended.

The underground chamber welcomed him like a second skin. Its walls were smooth, carved through earth and stone by layered waves of psychic will and chakra precision. The air was still, utterly sterile. No bacteria. No insects. No contamination. Every molecule had been sculpted clean.

He sealed the entry behind him and set down the scrolls.

With a faint psychic pulse, he unfurled them in midair. Dozens of animal bones, fish skeletons, powdered marrow, and shell fragments levitated around him. He extended one hand, and his thoughts rippled outward.

Bones disintegrated in midair, their mass broken into microscopic powder under telekinetic pressure. Dust shimmered as it hovered in psychic suspension.

He pressed his hands together, chakra and will blending into a sculptor's harmony. The powder compressed, not tightly, but carefully, shaped into soft bars layered with nutrients. He mixed in seaweed flakes and mineral salts, binding it all with chakra threads so it would dissolve easily in the gut.

Dozens of calcium nutrient bars hovered in the air around him, glinting faintly in the chamber's psychic light.

He stacked them neatly beside the surgical slab.

The Ossmodula floated within its nutrient vat, suspended in golden liquid, still and complete.

It had taken him a week to craft.

He'd grown it in the same way he had the secondary heart, starting from compatible cells, replicating the necessary tissues, forming the gland in stages under his psychic control and chakra sculpting. But this time, it was far harder. The Ossmodula wasn't just an organ, it was a gland that regulated transformation. It had to communicate with the central nervous system and the bloodstream. It had to trigger growth, but not overload. Precision was everything.

Each night, he had worked in this chamber, growing, carving, tuning it. During the day, he returned to the clinic. Bandaging patients. Sorting medicines. Training with chakra. Laughing with Shizune. Drinking tea in silence with Tsunade. Every day normal. Every night sacred.

They never knew that while they slept, he shaped his own evolution underground.

And now, it was time again.

He stood over the surgical stone and laid out his tools.

The gland would need to be placed between the cervical vertebrae, at the base of the skull near the spinal column, dangerously close to nerves and arteries. Any mistake could cause paralysis or death.

He would not allow mistakes.

He sat in silence and breathed deep.

Tomorrow night, he would perform the implantation.

He looked down at the calcium bars beside the tray and picked one up. It was warm, soft, earthy.

He took a bite. Chalky, bitter, but rich with what he needed.

He forced himself to eat two more.

His skeleton would soon begin to grow.

Longer.

Stronger.

Thicker.

He needed fuel.

He stared into the nutrient vat one last time, his face reflected in the golden light.

His hands did not tremble.

Only one step remained.

He was no longer afraid.

Only hungry.

And evolution was always hungry.

End of Chapter 34 – Bones of Growth