Re: Thanos' role in Age of Ultron
I suppose it's not really official per say, but I mean, what else could there possibly be? It's already super ambitious to be setting up a villain over such a long course of time, so I'd think it's unwise to keep his debut and relevance past Avengers 3.
Civil War would never work on screen anyways. Not when Marvel Studios is missing a lot of the crucial players to begin with. And even if they bought back every single right, it'd be a logistical nightmare to write a script for such a thing, and then double to actually film it.
Unless you pull an X-Men and focus on 1-4 characters while everyone is just standing to the side with nothing else to do but just be there for the hell of it.