One of the most infuriating aspects of the entire MCU is how little Thanos we've seen so far: he showed up in The Avengers for mere seconds, had one scene in Guardians of the Galaxy and a few more seconds in Age of Ultron, but considering that he's the ultimate big bad of the MCU, his presence has scarcely been felt. Don't expect that to change in Civil War, though, because while the film is basically The Avengers 2.5, Thanos isn't on any cast lists, and just a few months ago actor Josh Brolin still didn't know which movie he would first appear in (presumably it's Infinity War Part 1). Though a third act arrival from Thanos to force the two Civil War sides to team up leading into Infinity War would be one hell of a hook, it doesn't seem likely at all. The teasing will continue until 2018...