Satan is an advocate for humans in Jewish theology. I suppose Job was an exception. Christianity invented the evil Satan who seems an equal counterweight to God. I used to know where Christianity imported this concept. Strict Christian theology teaches that Satan, a created being, was doomed from the start. I've read somewhere that angels have no free will. We needed a scape goat. I wonder if Satan's development did not arise from the church trying to explain why Jesus triumphant allowed such suffering.
Good question. It raises such basic issues such as who/what is God. In Job, Jehover tolerates Satan. In fact, he seems not to function without Satan. God lowers himself to crass actions.
Within the last few years, I read a tome on Judas. Judas' concerns always struck me as noble. Most of the book was to show how paintings and other depictions of Satan changed over time. The very sad part was that Judas was identified as the archetype of a traitorous Jew. Genocide followed. Yet Jesus and the apostles were Jewish. A scapegoat was needed.
The most vile depictions of Jews surface in Judas art. Recently, though, Judas is portrayed as more heroic, a typical human, whose suffering is arbitrary from God. If Satan directed him, Judas had no free will. We need Judas to move the story along. I don't think Judas depictions evolved accidentally. Society changed and the pictures reflect that change. He is sort of an Everyman.