Ascendance of a Bookworm - Chapter 141: Maine Decimal Classification (119.2)

A teenager named Evan Mason was reincarnated into the magical world of Harry Potter and goes to school at Hogwarts!
With only his knowledge of the future and great talent for magic, he takes the path towards the top of the magic world, only to realize that ever step he took, changed everything!

- Description from Novelupdates

“Here's what happened. I was in a desperate situation when I accidentally encountered a dragon. It told me I was a martial arts prodigy and said it would teach me the Dao of Immortality…” “This excuse for skipping class and cultivating in secret… is that seriously the reason?” “I don’t care whether it’s human or not, what matters is that the dragon said: ‘If you want to become strong, kneel and call me Master.’”

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 …

He was an addict, a loser, a despicable human being.