Chakra amount is not only influenced by physical and spiritual energies but also by one's bloodline. If training increases chakra incrementally, then possessing the bloodline of the Otsutsuki clan amplifies it exponentially.
In the Naruto world, the Hashirama cells, a genetic legacy of the Senju clan, have proven challenging to integrate. Whether it's Yamato's (Tenzo) limited ability to produce wood release or Danzo's unstable arm grafts, using these cells typically results in serious limitations or side effects. Even Uchiha Madara, who achieved one of the best integrations, ended up with a manifestation of his friend's face on his chest.
However, this issue poses no significant hurdle for Shin, as the unique properties of his Munch-Munch Fruit ability allow for complete cellular integration—even metals can seamlessly merge with flesh. If Shin could easily fuse machinery into his body, integrating Hashirama's cells was hardly an obstacle.
This level of modification differed from Shin's past body enhancements. Previously, he restructured his body based on others' physiology. Now, however, he merely needed to merge the Senju cells directly with his own.
The dark mist enveloped the Hashirama cells and, later, the Sharingan from the Uchiha clan. Shin dealt a merciless blow to the unconscious Fugaku Uchiha, seizing his eyes and physique. After absorbing the man's chakra and flesh, Shin left a weakened Fugaku near Konoha, casting him aside.
To Shin, the ninja clans, Konoha, and even the profession itself held no allure or sympathy. While reading about ninjas in manga was entertaining, living in their world quickly eroded any romanticized ideals. After all, any ten-year-old could be forcibly sent to the battlefield. Shin held no illusions.
Shin noticed an extra Sharingan with the "Kamui" ability as he reviewed his spoils. "There's no place to put this," he muttered, storing it away. His fruit's swallowing power could theoretically fuse the Kamui eye with other Mangekyō eyes, creating an Eternal Mangekyō. However, merging a pair of Eternal Mangekyō Sharingan and a single Mangekyō Sharingan was difficult, so he chose to keep them separate. Thanks to his newly acquired dual Senju and Uchiha bloodlines, there was little risk of the typical Mangekyō blindness affecting him.
"The Uzumaki cells within Kushina resemble those of the Senju clan. Perhaps I can combine and fuse them. It's worth a try."
Shin spent an entire day experimenting with body modifications. Unlike other researchers, he could revert any unsatisfactory changes thanks to his devil fruit ability. He tested and revised over a hundred times until he was satisfied with the fused bloodlines of Senju, Uzumaki, and Uchiha.
After this exhaustive modification process, Shin almost completely disappeared from public view, immersing himself in studying the contents of the forbidden scroll and the medical knowledge acquired from Konoha's Root organization.
Konoha's extensive knowledge of ninjutsu and human anatomy was profound and enlightening. If it weren't for the shadow clone jutsu Shin mastered from the scroll, he would likely have needed decades to explore everything.
Shin split off several shadow clones to focus on various ninjutsu techniques and anatomical studies. He personally dedicated himself to mastering the Eight Gates, feeling that with his robust physique, the "sage body," and his Munch-Munch fruit ability to mend physical damage, he would waste his natural gifts if he didn't attempt to master them.
However, one obstacle remained: the "Dead Demon Consuming Seal" (Sealing Jutsu: Reaper Death Seal) was particularly troublesome. Not even Shin's dark-dark fruit power could break through this barrier. The seal remained intact on the deceased bodies; half of the Nine-Tails and Minato Namikaze were now sealed within the Shinigami's belly.
With this limitation, Shin abandoned his pursuit of the Nine-Tails' chakra, a slight blemish on an otherwise vast bounty.
Time passed, and two years flew by.
During these two years, Shin lay low while Konoha Village and the entire shinobi world experienced a quiet yet turbulent transformation.
Konoha had suffered devastating losses due to Shin's interference. The Root was nearly eradicated, the leader of the Uchiha clan had been gravely injured, and both the Fourth Hokage and his jinchuriki spouse had perished. The casualty count among Jonin alone matched that of a full-scale war.
The fallout left Konoha in a precarious position. While none of the other hidden villages wanted to rekindle a shinobi war so soon, they certainly saw opportunities to exploit Konoha's weakened state. With tensions simmering, several villages considered whether the time was ripe to act, though all feared the unpredictable consequences of another great war.
The Cloud Village, in particular, was the most overt in its ambitions, given that no formal peace treaty had been signed with Konoha. Their brazen attempts at extortion and intimidation only intensified.
Yet Shin paid little heed to this political turmoil. As a solitary operator, the world's shifting alliances meant little to him.
Konoha's pursuit of Shin remained limited, partly because they were spread too thin. However, they issued a bounty on his head in the black market, making Shin's moniker "Kurogami" infamous.
Consequently, other hidden villages, including Cloud, Stone, and even the Akatsuki organization, began showing interest in Shin.
Cloud Village, renowned for its ambition to gather rare bloodline techniques, coveted Shin's "dark release". With its pragmatic Tsuchikage, Onoki, Stone Village liked to recruit powerful bounty hunters and naturally sought contact with Shin. Meanwhile, the Akatsuki—especially Uchiha Obito, who had witnessed Shin's power firsthand—wanted to gauge his strength. Shin was a potentially valuable recruit with the Akatsuki's plans to expand.
But Shin had been in hiding, dedicating himself to training and research in an underground base, far removed from the world's prying eyes. Even the Akatsuki, with their network of Zetsu spies, struggled to locate him in the depths of remote forests.
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BONUS CHAPTER: 150 Powerstones achieved
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