Question: I need your input on one question, but one question as it applies to 2 characters.
I really want to try a work where the protagonist, or at least a major character very close to him, slowly (and not without good reason) becomes the/an antagonist. You might look at Sasuke Uchiha from Naruto to get an idea of just what I'm going for. My question is what do you think of that concept? I really don't want to have a story of them being corrupted by or joining with the book's main antagonist or going over to the dark side out of jealousy of his friends or anything like that. I want this character to become a true villain in his own right. How could that work out? How could it work for a main character/protagonist? How could it work for one very close to him? Any tips? Pointers? I'm just really tempted to try it, but I'm not sure where to start or where it could potentially lead. I know letting a story run its course is part of the fun, but I would still like a pro's opinion first. Thanks a lot!Answer:
One approach would be to make the main character the antagonist. That is, tell the story from his point of view, including how he came to pursue his evil intent of preventing the protagonist from achieving his goal.
Another approach is to write a classical tragedy, which is the story of an ambitious person who goes too far, ends up doing evil, and pays the price. (In that case the main character is the protagonist.) It often doesn't work out too well for the people close to him (e.g. Lady Macbeth).