Almost a full decade has gone by since Iron Man (Robert Downey Jr.) charmed his way into our hearts, effectively launching the Marvel Cinematic Universe. Now in a few months, we will see every other hero introduced so far assemble for INFINITY WAR, in what must be the most daunting cinematic undertaking ever. Joe and Anthony Russo must have handled it like champs, but according to the movie’s main villain, it's not a task they'll be rushing to sign up for in the future.

Josh Brolin (who plays Thanos in this massive two-parter – AVENGERS: INFINITY WAR and AVENGERS 4) spoke with Collider and said that assembling such a massive cast has been as difficult an undertaking as they come. In the end, he says the Russos seem confident this is their one, epic go at The Avengers:

Also, I think that they're in a position very openly and raw-ly where they're like, 'We would never do this again. This is a one-time deal.” To put this many successful actors together is such a pain in the ass, but it's been worth it. We're doing two movies. One back to back, and this is it for us. Then we'll go off in another direction,' but this is a very, very, very ambitious project that I think is going to pay off in a big way.

The Russos worked with a massive cast in CAPTAIN AMERICA: CIVIL WAR, but these next two movies also include Thor (Chris Hemsworth), Hulk (Mark Ruffalo), the Guardians of the Galaxy and so many more characters that it must have been an awesome nightmare to figure out. Brolin isn’t going as far as to say the directors won’t do another Marvel movie ever again, but something this big is probably not in the cards.

All that work should pay off though, as Brolin also praised the directors, saying Joe would often reference THE GODFATHER when working with actors on certain scenes. Principal photography for AVENGERS 4 began in August, so chances are there is still some work being done on both movies, with INFINITY WAR arriving May 4, 2018, and the next film a year later in May 2019. Everything is soooo close!

Concluding this ten-year saga cannot be an easy task, let alone doing it on such an epic scale and a vast, high-profile cast. On top of all that, the movie must be great. It MUST, or else people will be talking about why it wasn't until the end of time. Taking in all of that, I would not blame the Russos for never wanting to see another cape or pair of spandex ever again. Based on reactions to the footage out of Comic-Con this year, we can conclude the Russos have made a stirring summer blockbuster with INFINITY WAR, so if this is their AVENGERS swan song, at least they went out with a galactic bang.

AVENGERS: INFINITY WAR arrives on May 4, 2018.