Reincarnation of the Immortal

There is a shortage of books, so I might as well write one myself. Tags for this book, Reality Flow, Darkness Flow. The protagonist's enemies are all cowardly. Once they are hostile, they must be eradicated to prevent any stupid plot. In order to advance the plot, I set the protagonist as a person who cannot die, so that he can commit suicide at will. I believe you will also enjoy watching it.