One Piece: Dream of Immortality - Chapter 9: Separation

In the year Stardate 1, mankind entered the interstellar age, with interstellar migration, spaceships, alien races, and outer gods...arriving one after another.By the year Stardate 717, Fang Xing looked out upon the cosmic backdrop teeming with dense armies of foreign races and declared that all aliens, cultivators, tentacles, esoteric teachings, and evil gods would be intimidated by his supreme talent and smashed to pieces with his iron fist...Well, this is actually the story of a transmigrator, who whimsically dominates many different worlds with the help of his professional panel...

On a certain day, a certain thought came to Japan’s Sun Goddess. ——Aren’t there too many Japanese people being abducted to other worlds? It’s true that the large majority of Japanese are diligent and docile and soft-hearted, which makes them pretty much the best people to ask for favors. “But recently it’s just gotten way too out of hand…… Oh, I’ve got it! Whenever a Japanese person is summoned, I just have to summon an otherworlder!” And now, every time a Japanese person is summoned, princesses and elves and beastmen and whatnot are reverse-summoned. Under the acknowledgement of the government, they begin living in Japan. Today, too, Japan is at peace. And so begins this laidback isekai cultural exchange story♪

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

This is the story where Urahara Kisuke died after Nel failed to save him inside Askin’s Gift Ball Delux and reincarnated in the world of DxD.

I am not sure if I can capture Urahara’s character properly so I apologize in advance if you are not satisfied.

Also, English is not my native language.

I don’t own any of the characters from the canon.