I made a study of evil once, the history of the concept of good and evil that is; as every everyone ought; fascinating too it was. Evil, it turns out, has not been around all that long, has evolved rapidly and will be around for a while yet, but not necessarily forever. Evil was invented by people to serve one purpose or another both conveniently to avoid the effort thinking and usefully in a struggle against others. Evil became necessary when someone wanted to take something from someone else. Language (the word) took a dichotomous turn toward the mandalic paradoxical and the goodness of god suddenly needed an opposite. Sometime before 1229 the devil agrees to transcribe or translate a bible in which he also draws at that time, what we must therefore recognize as proper, a representation of himself; a picture of the devil in heavens basement, possibly planning his next caper.
Over the years the devil evolves to become a nasty piece of work in a runaway furnace in the basement of life. He and his (later development) minions, that I like to think of as a kind of military industrial outfit, become powerful tormenters of souls; of people; of towns; of cities; of races; of the entire world. He grows the wings and tail of a dragon. The devil shows up, without fail, where ever people want to swipe some gold hoard or other; whenever the little people need to be frightened out of their wits and wealth.