At Marvel Studios’ panel at this year’s San Diego Comic-Con, Kevin Feige and company dropped many, many bombs on their fans in terms of surprises. Aside from the plethora of new footage unveiled in Hall H from ‘Thor: The Dark World’, ‘Captain America: The Winter Soldier’, and ‘Guardians of the Galaxy’, the crowd went wild for a brand new teaser for Joss Whedon’s follow-up to ‘The Avengers’, which has been dubbed ‘The Avengers: Age of Ultron’.

Prior to the announcement, it was widely assumed that Phase Two was building towards a face off between Thanos (who was last seen in that now-famous post-credits scene) and Earth’s Mightiest Heroes, especially because of ‘Guardians’ being included in the schedule. With that mindset, it would be safe to assume that the Asgardian Avenger’s next solo feature and James Gunn’s intergalactic sci-fi adventure would be the cornerstones of this grouping of Marvel movies. But now that Whedon has revealed his plans for the Phase Two finale, things have changed for the general public. So which film is the most important lead in to ‘Age of Ultron’ now? That distinction goes to the Sentinel of Liberty.

According to an interview with The Huffington Post, ‘Captain America: The Winter Soldier’ co-director Joe Russo shared that the film that he and his brother are working on features strong connections to the last Avengers movie and the next one:

“There’s a very strong connection in the narrative between the events of the end of ‘The Avengers that drive this film — and there’s a very strong hand off to ‘The Avengers 2’ at the end of this movie. And Kevin Feige’s whole thing is that this is the biggest bridge of all of Phase 2 movies; it really is. It does involve the most amount of Avengers of any of the films in Phase 2, and it has sort of a, you know, there’s a very big shift in the universe at the end of this movie.”

Knowing what we know now, that makes a lot of sense. Also, Whedon’s comments saying that the Guardians of the Galaxy may not appear in ‘The Avengers 2’ make sense as well. However, what now are the plans for the Mad Titan moving forward? Why include him in ‘The Avengers’ if they’re not going to capitalize on the appearance? Well, previously, we learned that there are some long term plans in place for Thanos, but then what are the immediate plans for the wielder of the Infinity Gauntlet? Marvel Studios head Feige weighed in after the panel to discuss both Thanos and Ultron with IGN (via Comic Book Movie):

With the announcement of ‘The Avengers: Age of Ultron’, now it is believed that the main event match of Thanos vs. The Avengers will be reserved for ‘The Avengers 3’. But how will the transition work? We’ll probably have a better idea once the rest of Phase Two is released, but until then, I’m sure that you all have theories on what could happen between now and the end of Phase Three. Go ahead and share away in the comments.

‘The Avengers: Age of Ultron’ assembles in theaters on May 1, 2015.