The Goat of Mendes is a real thing, so is the Bay-a-Goatee.
They are demiurge.
The idea that there is not a manichean God and Satan is long standing, the Christian religion and the abrahamic religions dont suppose that the idea of God and Satan in perpetual, even matched struggle, that's an earlier idea from Zoroastarianism.
Satan was in the service of God in the old testament, perhaps a side or facet of God, perhaps an angel playing a role, the role which is called the "devil's advocate" today, Satan means "adversary", there's instances in the new testament of Jesus accusing others of "acting the Satan", its the literal translation of when he says "get behind me Satan" to his disciple (I cant remember which right now).
So it is perhaps a role that is played rather than an entity incarnate, although on the other hand the as many great thinkers have indicated and the movie the usual suspects used the greatest trick that the devil ever did was persuading people he didnt exist.
Ultimately, I believe, that even if Satan has God like powers in this world, the temporal, material world, its limited, its limited to this life, unless someone is fool enough to forfeit their soul somehow.