Naruto System in One Piece - Chapter 507

The Great Thousand World. It is a place where numerous planes intersect, a place where many clans live and a place where a group of lords assemble. The Heavenly Sovereigns appear one by one from the Lower Planes and they will all display a legend that others would desire as they pursue the road of being a ruler in this boundless world.

In the Endless Fire Territory that the Flame Emperor controls, thousands of fire blazes through the heavens.

Inside the Martial Realm, the power of the Martial Ancestor frightens the heaven and the earth.

At the West Heaven Temple, the might of the Emperor of a Hundred Battles is absolute.

In the Northern Desolate Hill, a place filled with thousands of graves, the Immortal Owner rules the world.

A boy from the Northern Spiritual Realm comes out, riding on a Nine Netherworld Bird, as he charges into the brilliant and diverse world. Just who can rule over their destiny of their path on becoming a Great Ruler? In the Great Thousand World, many strive to become a Great Ruler.

Bizarre clouds billowed by in the sky, as if in a hurry.

During an anti-drug operation in the city of Gongzhou three years ago, a chain explosion had gone off on site due to a mis-judgement made by the Commander-in-Chief Jiang Ting, and caused the anti-drug detachment team to suffer great casualties as a result. Three years now, Jiang Ting, who was supposed to have already been killed in the line of duty with not even a body left to bury—miraculously woke up from a coma.

His heroic soul had never been at peace. He returned from Hell back to the living, to give everything he had to bring the bloody and bizarre truth back to light.

- Description from Novelupdates

He is a young man without a spirit root. It is believed that this denies him the chance at cultivation. However, a mysterious lady imparts a Supreme Demon Classic to him and from then on, he starts his path of cultivation.
He undergoes a total transformation to emerge as the most fearsome and powerful fiendish demon in his era, that even immortals and fiends are fearful of him, and saints are at his beck and call.
Mastering the Supreme Demon Classic is the turning point in his life. He is able to unleash his immense and divine power from within, illuminating the entire universe!

Dao Fa leads to spirits, and medical therapy leads to ghosts.

A third-rate university graduate who was supposed to run around in a mess for his livelihood, but because of an inadvertent shot to save people, whether it is extremely peaceful and rewarding for his good people, he has obtained the legendary inheritance of the mysterious arts and medical methods of the experts in the realm of self-cultivation. Another brand new and weird new world!

- Description from novelbuddy