The Kidd here...
I've been hearing rumblings of this ever since that first post-credits in THE AVENGERS, which was then further cemented by Marvel Studios' announcement of GUARDIANS OF THE GALAXY... Thanos was going to be a major player in the next run of movies in the Marvel Movie Universe, leading up to THE AVENGERS 2.
Well, Cosmic Book News has confirmed with Thanos' creator Jim Starlin that Thanos will be appearing in both GUARDIANS and THE AVENGERS sequel, with it widely believed that the Infinity Gauntlet will play a big part in how the films all tie together, much like the Cosmic Cube did in Phase One.
This isn't all that surprising considering we've only scratched the surface with Thanos in his brief introduction at the end of Phase One, but at least we know pretty concretely where things are moving over the next five films.
"The Infamous Billy The Kidd"
Follow me on Twitter.