Keep Arthur C. Clarke's axiom in mind: Any sufficiently advanced technology is indistinguishable from magic. Magic is just a catch-all for that which we do not understand.

In my fantasy, there are no interventionist gods. People are adherents to religions though, but these religions are not necessarily true. They're just approximates of reason in a sub-technological world. In fact, in my fantasy I think of magic as an unexplained ability to affect matter on the sub-atomic level. People can heat, cool, expand and contract matter on that level. If you do it fast enough you have explosions, and if you do it slow enough you have curses.