Harry Potter's Most Vile Villains

There's no doubt that Voldemort is the baddest Harry Potter villain of them all, but the Dark Lord wasn't able to rise to power alone. Throughout all seven books and movies, Harry has had nemeses in various forms — from fellow students to teachers to house-elves. As we continue to gear up for the very last movie in the series, let's recount the rivalries that Harry and his friends have dealt with on the long journey to the final showdown. (Warning: if you haven't read the books, some spoilers ahead.)