Ask for a fantasy novel

The protagonist was a demon king who committed suicide at the critical moment in order not to hurt his sweetheart. And the Demon King's soul unexpectedly went to another world and was bestowed on the son of a prime minister. However, this person had done a lot of bad things in the past, and in the process of turning from bad to good, it was inevitable that he was pranked.
!!!! It's best to know the answer. Don't copy it casually. This 100 points is not something that I won't give you...!!!
I found it myself, it's a legend of madness

Answer 1

The name of one of the fantasy novels was Battle Through the Heavens. This was a novel written by Tian Can Tu Du, which told the story of a young man named Xiao Yan who rose to prominence during his training. He had gone through all sorts of challenges and tests, and finally became a powerful expert of the Dou Qi continent. This novel was also adapted into a manga and animation.