Ahh, that makes more sense.

... wait, does that imply there are non-supernatural (ie heaven and hell) sources of magic? Because I can think of other reasons why you wouldn't want to do business with a demon. Y'know, the whole "wants to torture your soul forever" thing might cause some issues.

EDIT: that is to say, is this intended to justify not using fairies or whatever other superstition? Because I doubt most people are ok with dealing with a demon (that is, something that has "torture all humans forever" as an explicit goal.)