The underground lab was silent except for the scratching of brushes on parchment. Kirito sat cross-legged, his expression grim and focused. Around him lay scrolls, jars of Sharingan, and dissected notes on Uchiha physiology. But today his attention was elsewhere.
Fuinjutsu.
He had touched upon its basics before—barrier tags, exploding notes, storage seals. But to hide his chakra core from the Byakugan and Root sensors, basic knowledge wouldn't suffice. He needed mastery.
---
Discovery of Ancient Scrolls
Among the scrolls stolen from Fugaku's personal chamber, one set had caught his eye. They were older than the others, the parchment faded and the ink nearly crumbling. Their markings didn't resemble standard Konoha sealing style—rather, they were closer to the Uzumaki script, sharp and flowing like chains binding themselves into infinity.
Kirito unfurled the first scroll. Words leapt out at him:
"To control chakra is to control existence. To bind chakra is to bind the soul."
His heart raced. These weren't mere storage seals. These were the foundations of advanced sealing jutsu, bordering on forbidden techniques.
---
Obsession and Isolation
Days turned to weeks. His routine became mechanical:
Mornings – D-rank missions handled by shadow clones.
Afternoons – Experiments on Sharingan, body preservation, and nervous system stimulation.
Nights – Tireless study of seals, redrawing and testing formula after formula.
He slept only when his body threatened to collapse, and even then, clones often replaced him to continue work.
Soon, the lab's walls were covered in sealing diagrams—ink spirals, linked kanji, chains of symbols glowing faintly from chakra infusion.
He experimented on everything: rats, preserved Uchiha eyes, even inert jars of chakra-infused water. Some seals exploded violently, scorching half his workspace. Others drained his chakra so fast he fainted, waking hours later in darkness.
But slowly, painfully, patterns emerged.
---
First Breakthrough – Concealment Seal
After a month of failure, Kirito succeeded.
He pressed his hand against his own chest, chakra flowing into a freshly drawn seal across his sternum. The ink vanished into his skin, leaving behind a faint mark like a spiral.
The result: silence.
His chakra core—once a blazing beacon visible to any sensor—became muted, wrapped in a cocoon of suppression. Even his clones struggled to feel it.
Kirito exhaled, relief flooding him.
"This… this is it. The Hyūga won't see me anymore. Danzo's hounds won't sniff me out."
The first chain of protection was forged.
---
Parallel Experiments – Sharingan Integration
With one problem solved, Kirito turned back to the eyes floating in chemical jars. He had dissected three Uchiha bodies already, mapping the intricate web between the optic nerves and chakra pathways.
The Sharingan was more than a dojutsu—it was an extension of the brain, tightly bound to the user's chakra flow. Simply implanting it led to rejection, blindness, or madness.
But what if seals could mediate the connection?
He inscribed a series of micro-seals around a preserved Uchiha eye, symbols designed to stabilize foreign chakra signatures. When chakra was funneled into the eye, it flickered—just for a second—the tomoe spun before going dormant again.
Kirito grinned.
"Almost alive. Almost ready."
---
The Second Breakthrough – Preservation Seal
Another success followed. By layering Uzumaki-style seals with his own modifications, he created stasis containers—scrolls that could hold organic tissue indefinitely without decay. The Sharingan, once fragile and time-sensitive, could now be preserved for years.
It was revolutionary.
He sealed Fugaku's Mangekyo Sharingan inside a special scroll, locking it with three layers of blood-activated barriers. Only his chakra signature could unseal it.
Now, even if Danzo discovered his lab, even if Root raided it, they could not touch his treasures.
---
Transformation of Mind
Weeks later, when Kirito looked at his reflection, he hardly recognized himself.
Dark circles framed his eyes, his hands bore permanent ink stains, and his mind constantly buzzed with sealing formulas. But behind the exhaustion burned an unmatched clarity.
He was no longer just a child ninja scraping by. He was becoming something else—something dangerous.
A sealing master in the making.
"Seals are the foundation of everything… and with them, I'll rewrite the limits of shinobi power."
His gaze drifted to the jars of Sharingan once more.
"Even the Uchiha's curse will bend to me."