Asked about the character potentially being the villain of the upcoming “Thor” sequel, Feige says “No, future, future. But there will be a major new villain. A major, major new antagonist”. The most frequently suggested guess right now on fan sites is the Enchantress.
One interesting thing Feige says about the “Thor” sequel is that it will show different areas of Asgard, not just the palaces of the ruling class – “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.”
Feige isn’t resting on his laurels, the success of “The Avengers” is no endgame for the company – “The Avengers was not the finale for us. It was a giant, giant marker, but it was never the finale. We are already well into the plan for the next phase of our little cinematic universe.”