I Was Possessed By An Unknown Manga - Chapter 13: The Secret of Strength

An ultimate warrior, the one and only Alchemy Emperor, Ling Han, died in his quest to achieve godhood. Ten thousands years later, he, with the ‘Invincible Heaven Scroll’, was reborn in the body of a young man with the same name. From then on, winds and clouds moved as he set himself against the uncountable geniuses of this new era. His path of becoming a legend has begun once more. Of all eras underneath the heavens, I am the strongest!

- Description from Novelupdates

Yu Zhengdu joined a small start-up company that claim to offer “life management services”……as a programmer.

On his first day in office, he received a phone call from a stranger: “Hello, I received a text message from your company that informed me of my reincarnation tomorrow……”

Yu Zhengdu: “……??”

Shang Que, the beautiful little boss, said, “New employee, welcome to the Hell organisation in the human world. A thousand years ago, I was known to the human world as the Ghost King of Luofeng Mountain.”

Yu Zhengdu: “……??” From then on, he was incredibly distressed about the development of Hell.

- Description from Novelupdates

He never performed well in either middle nor high school, and even after becoming an adult, he never worked. Be it morning, noon or night, he only played an online game. For him, being the world’s number one rank, playing that online game, was his very reason for living.

One day, his account was hacked and his character deleted. Restoration was impossible. Nothing that could be done. The number 1 rank that he literally spent his life to attain and to defend was now lost. Filled with despair, he turned to suicide.

When he opened his eyes again, there was the online game. No, the world itself looked similar to the game. He had been reborn as the extra character of the premium avatar he created in the past, but left untouched.

The former world’s top, was reborn in a world that looked like that online game. That was the beginning of his extraordinary legend.

A knight, a cat, a dark elf, and so on. Together with several unique companions, his training to regain his “world’s first rank” now begins.

A soul was employed by a higher being to help him manage his world. How will our protagonist live her life to the fullest while also fulfilling her new duties?I don't own Naruto. I adjusted the story to my liking. English is not my main language so don't bother about grammar mistakes too much.