You are spouting nonsense. First of all he doesn't have to care because he is the Herald of god of darkness.
Second everything he assimilated influenced him with the traits, even if he suppressed them later on he still got a totally different persona.
Third the more you delve into the story and the more he kills without caring, as any veteran warrior would do, in a world you could kill thousands with a wave of your hand.
Your point is influenced by your irl persona, and you are not trying to view this in his place
