One Piece: As a Marine With Rinnegan

East Blue, Cocoyashi Village

"Chika, are you going out to sea today?" An old lady stood at the entrance of a meat shop, shouting at a young boy. The boy was slender, handsome, nearly two meters tall, with a cold expression. His black hair was casually tied up, and he had fair skin. He wore a black robe with a ping-pong ball-like pattern on his back and a pair of brown gloves on his hands.

The most unforgettable aspect about him was his eyes. They were a pair of purple eyes, each with concentric black patterns, emanating mystery and danger.

A faint smile appeared on the boy's cold face as he nodded in response to the old lady.

The boy's name was Uchiha Chika, but he didn't belong to this world. Originally from a planet Earth, he was an orphan who accidentally traveled to the world of Naruto in a manga. He became a member of the Uchiha clan.

Thereafter his new parents gave him the name Uchiha Chika, they died on the battlefield. With his memories from his previous life, he became friends with the young Hatake Kakashi and learned the Flying Thunder God technique. He believed he had the strength to protect himself. Taking advantage of a mission, he faked his death and stayed outside of Konoha.

That's how he grew up in the outside world, relying on the memories of Earth. He made a deal with Orochimaru, using some information to gain the Senju cells. With Orochimaru's help, he successfully fused the power of the Uchiha and Senju clans, awakening his own Rinnegan Eye.

However, just as he was immersed in the joy of awakening his eye, Orochimaru ambushed him, causing him to overexert his newly born eye and use the unfamiliar power of space. As a result, he lost consciousness.

When he regained consciousness, he found himself on a small island, and his body had regressed to the age of six.

He quickly checked his current body condition after the transmigration. Fortunately, the hard-earned Hashirama cells and the Rinnegan Eye were still there. Due to his body's regression and the eye's overexertion, he couldn't use much of his power.

After all, this wasn't his first time transmigrating, so he quickly adjusted his emotions. He spent a day exploring the island until he found the village named Cocoyashi.

While in the village, he saw a woman with burgundy hair accompanied by two little girls. The distant memories of his previous life reminded him that he had arrived in the world of One Piece.

Since he was here, he decided to settle down. Although the villagers were afraid of his eyes, the old lady, Lisa, who ran the meat shop, couldn't bear to see a six-year-old child wandering alone and took him in.

Afterward, he lived in this village, patiently waiting for his body to mature and for him to adapt to the power of his eyes. Now, it had been ten years.

"This should be enough. Although the overuse earlier prevented my Rinnegan Eye's unique ability from manifesting, thanks to the peculiarities of the One Piece world in terms of food and other aspects, my body seems to have developed even stronger than before. The fusion of Hashirama cells and my body is already perfect. It's no wonder this is a world where almost everyone is a powerhouse. I've turned a misfortune into a blessing," Chika thought.

He clenched his fist, feeling the surging power within him, and his heart surged with excitement.

Chika estimated his current strength in the absence of various special abilities based on his performance in the previous anime world. He believed that he had reached the level of an ordinary Rear Admiral in the Marine, but there was still a considerable distance to becoming an Admiral.

However, he believed that with his body's better development and subsequent exposure to the power system of the One Piece world, surpassing his previous self and becoming a top-tier figure in this world was inevitable, and it wouldn't take much time.

"It's time to set sail and explore this world of pirates. Maybe I can break through here again and become a true Six Paths Sage."

In this life, he decided to temporarily join the Marines.

One reason for joining the Marines was that as a former Earthling, he had a greater sense of identification with the military and had reservations about being a pirate. Although the Marines in the world of pirates had some corruption and flaws, overall they were still good, and they represented the official side.

On the other hand, apart from the protagonist's group and a few other pirates, most pirates were ruthless criminals who burned, killed, and looted. Chika didn't consider himself a saint, but he had his own moral bottom line. In the Naruto world, he would kill those who deserved it, but he still had his own principles.

Another reason was that joining the Marines would allow him to learn about the power system of this world and have more opportunities to encounter the unique features of the One Piece world, namely Devil Fruits.

He didn't plan on eating Devil Fruits since with his Rinnegan Eye, he already possessed six types of chakra nature transformations, and the Nature element held little significance for him.

The over a thousand ninjutsu techniques he copied during his Sharingan period didn't require the so-called Superman element either. As for the Animal element, it was redundant for him, who already possessed the Senju cells and the Sage Mode.

So why burden himself with the weakness of being a Devil Fruit user? However, he had a thought he wanted to confirm: whether his Rinnegan Eye's Preta Path could affect the abilities of Devil Fruits or their users. And could he use the power of Devil Fruits to further evolve his Rinnegan Eye?

He had a premonition that this might be his opportunity to break through himself.

Putting his thoughts aside, Chika decided to go out to sea one last time to catch some fish. He intended to catch more this time since the meat shop might face shortages after he left.