The Regressed Demon Lord is Kind

My whole life, all I wanted was power.I churned the world into rivers of blood and eventually gained the title, «Demon Lord of Strength». However, all this became useless when I lost to a party of heroes.But what can a loser say? As I laid dying, I was forced to listen to the hero’s gibberish:«If you are born again, I hope that you will live a kind life!»But huh? When I opened my eyes again, I was back in the past.«What do I have to do to live a kind life?»This is the beginning of an ex-Demon Lord’s journey to live a kind life.