In general, the Avengers don’t assemble for minor threats. With a moniker like Earth’s Mightiest Heroes, it takes a threat unlike any other to bring the team together and propel into battle. However in ‘Avengers: Age of Ultron,’ this fight might be a little bit too much for the team according to a certain member who knows a thing or two about fights.

During a recent visit to the set of the highly anticipated Marvel Studios movie, /Film spoke with ‘Thor’ and ‘Thor: The Dark World’ star Chris Hemsworth about what sort of threats the God of Thunder and his allies face in Joss Whedon’s upcoming Phase Two film. Despite the many wars that Thor has waged throughout the Nine Realms, the actor says that Odinson expresses the possibility of defeat this time at the hands of Ultron:

“I think [Thor] openly admits, ‘I don’t think we’re going to win this one’. The threat is so great that I think all of them are sort of scratching their heads going, ‘Is this it?’ rather than, ‘Okay, we have to kill this many things’. It’s just an onslaught and it doesn’t stop. It’s sort of an open sort of floodgate and what it could also set in motion is an even bigger threat. I think that’s what’s Thor’s kind of stuck on or where his is attention certainly is, an even bigger picture of Thor being from Asgard. He can just say, ‘Hang on, there’s a whole universe here which is signaling something else’.”

But the deranged and enraged robot isn’t the only obstacle that the Avengers must overcome. Before joining forces with the team, Elizabeth Olsen’s Scarlet Witch conjures up some trouble that finds each hero basically facing their greatest fears:

“I think it certainly creates a conflict. It’s more kind of within their individual selves rather than the team so much. I think they’ll begin to have their fears held up in front of them. For Thor, I think it’s a corruption of power. With all of them having this much power and trying to have the understanding that we’re in this sort of endless battle here and when this is going to end and how does it end? That’s where he really starts to kind of move through the story. Once that dream occurs he goes, ‘Oh, I can see what’s coming and my fear could be true’ so yeah, it’s a ticking clock.”

Finally, regardless of how much trouble our heroes face in front of the camera, things are being shaken up behind the scenes as well, except in a very good way thanks to new faces on set like James Spader and Paul Bettany (whose voice has only appeared in the MCU up until now):

“It’s awesome, you know? It just shakes things, because–and I find this in my individual films–you get comfortable. We get into a rhythm or a routine and you think you know it. Until that’s challenged you kind of go ‘Oh, yeah, that’s right. There is another option here’ and you can keep changing it and mixing it up. That’s what this new cast does is all of a sudden, it breaks the familiar rhythm that we may have and makes it a bit more unpredictable. We’re lucky. To come back and actually want to come back and work with these guys and hang out again and pick up where we left off is a pretty special thing, and it’s been great. I do love working on this set.”

Are you excited to see the heroes of the Marvel Cinematic Universe take on these new threats in ‘Avengers: Age of Ultron’? What do you expect to happen to the newly Earthbound Thor in his next big screen appearance? Share your thoughts in the comments below.

‘Avengers: Age of Ultron’ starring Chris Evans, Chris Hemsworth, Mark Ruffalo, Scarlet Johannson, Jeremy Renner, Robert Downey Jr., Elizabeth Olsen, Aaron Taylor-Johnson, Paul Bettany, and James Spader assembles in theaters on May 1, 2015.