One Piece: Dream of Immortality - Chapter 62: Whoops

Chen Rui, an otaku from earth, is reborn into a human body in another world, who falls into the legendary evil, brutal world of the devil called Mozu where humans are treated as food. He has to survive while facing horrors of the devil, violent dragons and a variety of power enemies depending on a strange super system chip and his wits. Surrounded by Devil’s beauties such as black-bellied lolita princess, cold queens, violent dragons, charming poisonous devils …

Wanting to live in the Devil’s world is hard! Wanting to live in the Devil’s world as a human is harder! Wanting a human to be the devil’s son-in-law is hardest!

Let us see how a small otaku uses power and strategy step by step starting from an ordinary human to writing a legend as the devil’s greatest son-in-law.

- Description from Novelupdates

After rebirth, she, who used to be a top international spy, becomes the eldest daughter of the Fengs, a fat girl who is ugly and foolish in the eyes of the ordinary people.
Mastering Royal 18 Saber Moves and Purgatory 9 Palms, she rose to fame with the martial arts of Demon Cook.
Upon an imperial edict, she was ennobled as the wife of Lord Cen, and then suffered various intrigues and plots…
She proved herself to be a real overmatch and a true genius to the world…

In the middle of a deserted island, a small boy wakes up with two sets of memories: one from his few years of life and the other from a man who lived to adulthood and achieved great things. When he least expected it, a powerful master appeared on the island and took him in as a disciple, revealing a shocking fact: magic exists in that world, and, thanks to it, humanity managed to conquer the galaxy.

The strongest Demon Lord dies, and reincarnates as a human. Not only that, he because of various incidents turns into the hero’s best friend.

Follow his journey as he tries to help the hero escape his fate, and on the sideline to conquer the continent while he’s at it.