It may seem like it's Iron Man 3 that has had the Marvel market cornered on adding new villains, but Thor 2 is the film that has the most question marks surrounding the cast. It's Thor's upcoming adventure that will likely feel the greatest impact from The Avengers, even if it's Iron Man will see first. We know who every single bad guy in Iron Man 3 will be, and have a good idea of the storyline. What do we know about the Thor sequel? Not a heck of a lot. It's fortunate that we have Marvel Prez Kevin Feige to shed a few details.
I'm going to assume that everybody has seen The Avengers by this point? Yeah? Good, because I'm about to spoil the ending. The film basically ends with Thor launching himself into the stars and headed back to Asgard with Loki in tow, and carrying the Cosmic Cube. It's soon after that we are introduced to the Mad Titan himself, Thanos, who is apparently the real power behind everything that went down. It didn't seem likely that Thanos would be the main baddie for Thor 2, with yours truly assuming that he'd play a behind-the-scenes role. Feige, while talking to Empire, seemed to confirm that as well...
Feige: “No, future, future. But there will be a major new villain. A major, major new antagonist…”

Feige: “We’re going to see the other side of Asgard. It’s not all polished and golden in this film. And the events of Avengers will have affected Thor for sure. His relationship with Loki will continue to evolve, and the biggest part is Natalie and Thor returning with Jane Foster.”

Alan Taylor (Game of Thrones) steps into the director's chair when Thor 2 begins filming this summer for a release on November 15th 2013.