Joss Whedon has claimed that Thanos was never designed to be the villain in the upcoming Avengers sequel, despite his appearance at the end of the first film:
Speaking to Total Film, the director says that while Thanos is a part of the Marvel Universe – and will be seen in Guardians of the Galaxy – he will not be opposing Nick Fury’s band of heroes, a role that will be filled by Ultron.
“We have to stay grounded. It’s part of what makes the Marvel universe click – their relationship to the real world. It’s science-fiction, and Thanos is not out of the mix, but Thanos was never meant to be the next villain. He’s always been the overlord of villainy & darkness.”
Whedon also spoke about the Ultron character, and whether his starring role in the film will also bring appearances by his creator Hank Pym, or the android that Ultron himself created, The Vision:
“We’re not going to see Pym and all the accouterments. Ultron is more central to the Avengers as they are. But we will explore the idea of lineage, because he was created by us and we’ve got to own that… Then we have the Scarlet Witch and Quicksilver and I think that’s plenty, because Quicksilver and Scarlet Witch did not begin their time as friends of the Avengers, so there’s going to be a lot of, well, conflict.”
The Avengers: Age of Ultron begins filming next March, with release scheduled for May 1 2015.