Naruto System in One Piece - Chapter 520

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.

When an era came to an end, various forces set foot in cultivation to compete for immortality. A young boy who spent most of the time sleeping got lucky in the troubled times and became an unparalleled immortal who could cover the sky with a snap of fingers. Was he going to live forever?

- Description from Novelupdates

Hagoromo Gensou transmigrated to the Naruto world and, through his own efforts, became a prominent figure in the ninja world.Until one day, the newly appointed Five Kage teamed up and ambushed him immorally. It was only then that the system finally appeared, claiming it could help him rise to become the strongest in the ninja world.However...Just as he was about to confront the Five Kage head-on, Gensou silently looked at the first task issued by the system.[Quest: Ninja School Comeback Initiated! Please defeat your dead-last classmate, Uzumaki Naruto.]“System, do you know what year it is now?”[Year 60 of Konoha]“Right now, it's Year 2 of Konoha! Is there something wrong with this system?!”...Many years later, Gensou opened his eyes again, standing on the rooftop of the Chunin Exams building. Looking at the Third Hokage, who was ready for battle, he smirked slightly:“Although it's a few decades early, I finally made it.”[Raw: 火影：我都硬刚五影了，系统才来]