In my current WIP I'm toying with the idea of taking the traditional protagonist vs. antagonist struggle -- the one in which the reader stays within the cozy confines of the heros head -- and sort of flipping it around. The approach would be to begin the story in a traditional sense, and as the characters interact in the story, the reader eventually starts to feel protagonistic about the antagonist and vice-versa (perhaps). My "antagonist" is a supernatural being of sorts, is quite violent, manipulative, and self-serving. The big question is how to develop this character throughout the story so that by the end, readers have a completely different take on him? I'm thinking some sort of unexpected element of compassion has to pop up somewhere in his arc. But not quite sure just what.