The Demon King is Strong and Overly Diligent

Synopsis: I am a great demon king, striving, diligent, hardworking, and capable of doing many things, occasionally supporting the righteous path once, saving the world a few times, cultivating a few plane children, is that too much? The Demon Realm is destroyed? Everyone, don't be nervous, as I said, I am a great demon king, occasionally destroying the Demon Realm a bit, enlightening all the demons, isn't that reasonable?