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.
I'm sure it's been done before. Protagonist and Antagonist don't necessarily mean good guy and bad guy. The guy that the story is built around is the protagonist, and the antagonist is the guy he is in conflict with. Hitler could be your protagonist if you really wanted. So you could make anyone you want your protagonist. And I'm sure at some point I've read a story where the bad guy ends up being redeemed (although maybe not both in the same story). However, if you were to do a story like this, I wouldn't just do it to do it. I think it would be best if your story have a point. Usually with stories where a good guy turns bad or a bad guy turns good... there is a point being made.
Yes, I understand that. But in the traditional sense they do. I'm not talking about establishing a "bad guy" as the protagonist . I'm proposing the establishment of the traditional protagonist/antagonist scenario and having those roles gradually evolve into the total opposite. I agree with this. There has to be a point to it. A theme behind the transformation, if you will.
So you are just saying you want your "bad" guy to be good in the end and maybe vice versa. It's certainly possible. I think it would be easier to do just one or the other rather than both actually. Because it's easy to have the "bad" guy realize what he's doing is bad, or maybe redeem himself in some way. And it's certainly easy to have the good guy slowly turn "bad" maybe his personality quirks get the best of him (someone out for revenge for example). Or it would be easy to have two people kind of start out neutral and then it turns out the guy you have declared as the protagonist turns out to be bad in the end and the other guy turns out to be good.
What you describe sounds entirely doable, and not very controversial, to me. You can make the "villain" more and more sympathetic just by describing things from their point of view. Gradually, the reader understands why they're doing what they're doing, and may eventually agree that it's for the best.