One Piece – Thundergod Marine - Chapter 15 Too Much

The Heavenly Dao has shifted, demons rise from all corners, and the powers of Cultivation need to be enhanced. The Immortal Venerable's Order commands us to diligently cultivate, slay demons, exterminate evil, purge demons to protect the Dao, and elevate the might of Huaxia...

Zhao Yu transmigrated to the body of a down-and-out loose cultivator in the Canglong Mountain range of the Cultivation World, and discovered that he had awakened the ability to devour the Dao fruits, which allowed him to enhance his cultivation talent by consuming heavenly materials and earthly treasures, as well as elixirs. Ultimately, through the power of devouring the path’s fruit and his own efforts, he became a colossus in the world of immortals.

Chen Sha came to a world of immortal martial arts and was ordered to take charge of the world’s first sect.

Before his death, the previous chief told him:

“If you don’t become the best in the world for one day, you are not allowed to go down the mountain for one day.”

So he closed himself in painstakingly, crossed the heaven gate in his body, and faced off against the ancient and modern powerhouses…

…

Many years later, Chen Sha recalled the day he went down the mountain,

From the moment he descended the mountain, he was number one in the world.

In the next ten epochs, any gods and demons have returned, immortals and Buddhas have lived in the world, ancient powers and ancient gods have appeared one after another.

No matter how the times change, he has always been No. 1 in the world and has never changed.

- Description from novelbuddy