I do hold the opinion that Satan is an angel that fell. As far as I can see, the whole material plane we inhabit is literally the mind of Satan because he was given the responsibility of guiding mankind through the world of matter but he rebelled because he didn't want to be mankind's servant.
Although Satan is "Lord of the world" and we see his Logos everywhere, he only has dominion over matter, not the spirit and that's crucial! Thus, he can only tempt us into corruption, if we allow him to!
Thanks for the description of The Dice Man. There is a play running in London, at the moment that deals with the same scenario. I wonder if it's based on this novel? I'll try to find out...