One Piece - I Am A Different Luffy! - Chapter 52 - 51 - Mysterious Island 5.

At the end of a Dynasty filled with Demons and rampant Martial Artists, Lin Xuankong has unfortunately transmigrated to this era, becoming a poor and sickly old man. However, with the help of the system Life Plate, his Talent and Comprehension grow stronger the longer he lives.And his much younger wife is a martial master...“That iron ball used to be Zhang Wu's knife. I squeezed it a couple of times, and it ended up like this! ” said his wife.“I hope you can teach me some Cultivation Techniques. As for the reward...” said Lin eagerly.

An editor at the prime of her life—and with maybe just a little too much free time—finds herself waking up in one of her favorite RPGs with no clue as to what's going on or how to get back home.This might be the part where others rejoice over getting whisked away to a world of wizards and magic, but she certainly doesn't think it's anything to celebrate about.After all, she woke up in the body of a small-time villain with some severe personality issues.

“I can’t do it anymore. Stop it…I can’t take it anymore!” The second young master stopped in his tracks and raised his brows as he stared at Miss Jiang. “All you had to do was jog, so—”

Everyone knew that Miss Jiang was an artiste who had been defamed and blacklisted before she became famous again. When she got into trouble, she did not give up but fought persistently. Everyone knew that the second young master was the mysterious head of the enterprise. He was an extremely cold person with an exquisite taste. Moreover, the second young master had recently adopted a new hobby. He took in his younger brother’s ex-fiancée and he was extremely fond of her…

- Description from Novelupdates

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