The Ruler Of Darkness - Chapter 21Book 2:

Akira Kisaragi traverses into the Bleach world, unlocking a check-in system.He initially thought that by checking in daily, he could become stronger, soon become the Captain-Commander, join Division Zero, punch Yhwach, kick the Soul King, and marry Unohana...However, the system's style wasn't quite what he had imagined.〈 Check-in complete, obtained Genryūsai Yamamoto's secret roasted sweet potato! 〉〈 Check-in complete, obtained exclusive attribute: King of Normal Attacks, effect... 〉〈 Check-in complete, obtained Retsu Unohana's... 〉Akira's eyes suddenly lit up!“Seems like this might not be so bad after all!”

Everything was going so well. It was the perfect path toward greatness.

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

“Reincarnated into the World of Magic as a demon, the last thing Davis expected was to grow up right amidst the arms of angels. Ever since the group of philanthropic angels took pity on his miserable birth and adopted him, Davis has been forced to keep his evil identity a secret while he signed in to the system.

“”Ding! The Host has signed in at Angel’s Pond, ‘The Saint’s Halo’ is rewarded!””

“”Ding! Devil’s blood activated. Sign in error. ‘The Devil’s Curse’ is additionally rewarded!””

“”Ding! The Host has signed in at God’s Throne, ‘Gold’s Holy Axe’ is rewarded!””

“”Ding! Devil’s blood activated. Sign in error. ‘The Devil’s Manifistation’ is additionally rewarded!””

After a thousand years of quietly signing into places in the City of Angels and being rewarded with double the rewards, Davis’s true identity finally came to light! Now as a true Devil, Davis had both the world of angels and demons surrendering at his feet!”