The Strongest War God - Chapter 35

Crossing into the world of Naruto, and acquiring the One Piece system, with all the powers of the world of One Piece, swordsmanship, devil fruit, domineering.

-Do you think that your fire is very powerful? I have the burning fruit.

-Do you think that your thunder is very powerful? I have a thundering fruit.

-Do you think that your otter is very powerful? I have the frozen fruit.

-Did you said you want to die? Don’t worry, I also have a nickname: Death Doctor.

- Description from Novelupdates

A story about a traveler who crossed into a parallel universe, relying on his Proficiency ability to continuously grind experience and become stronger.

What if something made Naruto the dead-last that everyone perceives him to be? What if he really wasn't as weak as he appeared? The true Naruto, unleashed upon the shinobi world! AU story starts at the Konoha Invasion arc and continues from there..

Jin-Ho Kang was just another B-rank Hunter—one of countless warriors struggling to rise in a world dominated by monsters and guild politics. When an A-rank dungeon scouting mission goes horribly wrong, he and his team are slaughtered. He should have died.But instead of death, he awakens in an abyss beyond mortal comprehension. A voice older than time itself speaks to him, a decree is made, and the truth is revealed—he is no longer human. He has inherited a power that was never meant to be his.The world forgot him.But he has returned.As a Sovereign.As the Monarch of Shadows.And as the boundaries between life and death begin to blur, the world will soon realize…The true King has awakened.