I’ve heard it said that the Devil’s greatest trick was convincing us that he no longer exists. That would be a neat trick, but I can think of a better one. If I were the Devil I’d have tried this instead:
Long ago, when there was much more space than people, I would have gone to each isolated population, in turn, and convinced them that I was God (I would do this by making myself look exactly like the people I wished to fool, only bigger).
I would have instructed them in the rituals necessary for them to worship me—different rituals for each population.
I would have told each of them, in turn, that I had chosen them as my favored race, and—instead of hiding my existence—I would have insisted that not only did the Devil exist, but that his evil was rampant.
I would have told each of them, in turn, that evil lurked especially in the hearts of men, and that one would know an evil heart by virtue of the fact that its owner worshipped another god, a false god, a god who was none other than the Devil himself.
After that, I may as well not exist. All the evil I could wish for would be propagated by my congregants, without my ever having to lift a finger again.