i dont think he is the villain per se. im still of the belief that SW is the story of Anakin Skywalker. the young boy who became too powerful for the galaxy and was lured by "temptation" and then redeemed himself. you could say that "temptation" is the villain since it peeks its head out more than once. and since its the story of AS, and he redeems himself at the end, then he has vanquished the villain.