East Blue, Cocoyasi Village
"Kaito, are you heading out to sea today?"
An old woman standing at the entrance of the butcher shop called out to a young man. The boy had a tall, slender build and strikingly handsome features. He stood close to two meters tall, his expression cold and stern. His black hair was casually tied back, his skin pale, and he wore a long black robe. On his back was a symbol resembling a ping-pong paddle, and his hands were gloved in brown leather.
But what left the deepest impression were his eyes—those violet eyes, each ringed with concentric black patterns, radiating both mystery and danger.
A faint smile appeared on the boy's chilly face. He nodded slightly in response to the old woman.
The boy's name was Uchiha Kaito. To be precise, he didn't originally belong to this world. He came from a planet called Earth. Orphaned, he unexpectedly transmigrated into the world of the Naruto manga and became a member of the Uchiha clan.
There, his second-life parents gave him the name Uchiha Kaito, but soon after, they died on the battlefield. Relying on memories from his past life, he became friends with the young Minato Namikaze. After learning the Flying Thunder God Technique, he considered himself capable of self-preservation. Then, seizing the chance during a mission, he faked his death and stayed hidden outside of Konoha.
In this way, he quietly developed in secret. Using his memories from Earth, he traded intel with Orochimaru. Eventually, with Orochimaru's help, he successfully fused the powers of the Uchiha and Senju clans and awakened his own Rinnegan.
But just as he was immersed in the joy of awakening his eyes, he was ambushed by Orochimaru. In desperation, he overused his newly awakened ocular powers and attempted to use a space-time ability he hadn't yet mastered. He blacked out soon after.
When he regained consciousness, he found himself on a small island—his body reverted to that of a six-year-old.
He quickly examined his new body. Fortunately, the hard-earned Hashirama cells and the Rinnegan were still intact. However, due to the regression and the strain on his eyes, the power he could currently wield was limited.
Since this wasn't his first time transmigrating, he adjusted his mood quickly. After a day of exploring, he discovered this village—Cocoyasi.
When he saw a red-haired woman named Bell-mère, caring for two young girls, distant memories from his past life stirred once more. He realized he had arrived in the world of One Piece.
Since he was here, he decided to make peace with it. The villagers were simple and kind. Though his eyes made them uneasy, Granny Lisa from the butcher shop took pity on a six-year-old wanderer and took him in.
So he settled in the village, patiently waiting for his body to develop and adjust to the power of his eyes. It's been ten years since then.
He is now sixteen.
"Just about time. Although the strain from back then kept the Rinnegan's unique abilities from fully manifesting, the food and other aspects of this world seem to have helped my body grow stronger than before. The Hashirama cells have perfectly fused with my body... As expected of a world where nearly everyone is a walking tank. I guess it's a blessing in disguise?" Kaito thought.
Clenching his fist, he felt the power surging within him once more. His heart swelled with excitement.
Based on his previous life's understanding of power levels in anime, he estimated that in his current state—without using any special abilities—he was roughly on par with a standard Marine Vice Admiral. Still some way to go before reaching Admiral level.
But he believed that with further physical development and contact with the power systems of the One Piece world, surpassing the Kaito of his past life and reaching the top here was inevitable—and wouldn't take long.
"It's time to head out to sea. In this One Piece world, maybe I can break through once again… and truly become a Sage of Six Paths."
In this life, he planned to join the Marines—at least for now.
On one hand, as someone who used to be from Earth, he naturally felt more aligned with the military. He instinctively disliked pirates. While the Marines had their share of corruption and flaws, they were mostly a force for good—and officially sanctioned, at that.
Most pirates, aside from the main crew and a few others, were the kind who murdered, looted, and pillaged. Kaito wouldn't call himself a saint—in his time in the ninja world, he killed those who crossed him without hesitation—but he still had a moral baseline.
On the other hand, joining the Marines would let him study this world's power system, and more importantly, give him more chances to come into contact with one of its defining features: Devil Fruits.
He had no intention of eating a Devil Fruit himself. With the Rinnegan, he already controlled six chakra nature transformations. Logia-type powers meant little to him.
The hundreds of jutsu he had copied back when he still had the Sharingan made most Paramecia abilities unnecessary. As for Zoan types—now that he had the Sage Body via Hashirama cells, they were redundant.
So why burden himself with the Devil Fruit weakness of being unable to swim? Still, there was one idea he wanted to confirm—could the Rinnegan's Preta Path absorb the powers of Devil Fruits or the abilities of Devil Fruit users? Could he use Devil Fruit energy to further evolve his Rinnegan?
He had a hunch that this might be the key to breaking through his current limits.
Snapping himself out of his thoughts, Kaito decided to go out to sea one last time to fish. He needed to catch more than usual—after all, once he left, Granny Lisa might have trouble restocking her supplies.