“If I don’t die... I swear I will act on all my evil thoughts..”

Not exactly everyone’s typical thought when they’re about to die. What will a cowardly young man do when reincarnated with the evil powers to redefine his destiny? Can the natural kindness of human nature triumph over evil? Will he become the cold-blooded demon king of legend, or will he forge his own path and rain down another kind of terror?