The Russo Brothers continued trying to one-up themselves with every Marvel Studios project they took on. Initially joining the Marvel Cinematic Universe with 2014's "Captain America: The Winter Soldier," the Russos would soon finish the "Captain America" trilogy with "Civil War," a film that would be much more of an ensemble piece compared to "Winter Soldier." Marvel Studios head Kevin Feige was undoubtedly impressed with the Russo Brothers' work, moving them to two of the biggest films in development at that point: "Avengers: Infinity War" and "Avengers: Endgame."

A massive two-part story, "Infinity War" and "Endgame," would require the Russos to shoot both films back to back. Although the stories are interconnected, the character arcs, scenes, and set pieces would all be enmeshed between the two films, giving the director duo an arduous task of balancing the stories while providing a satisfying conclusion. The films took a toll on the directors, with the production blurring the line between one film and the other.

Creatively Rewarding, Physically Exhausting

While breaking down their filmography in a YouTube video for GQ, the Russos lamented the massive production of "Infinity War" and "Endgame," with Anthony Russo speaking on the laborious process of such an enormous undertaking:

"It's not good for your health, that's for sure. It was difficult. I remember all of us at the end said, "Oh, we'll never shoot two movies like that, back-to-back, ever again."

However difficult it was, the filmmakers still found a silver lining, detailing the benefit of shooting two projects in tandem:

"It really did allow for a big interplay between what we were doing in the two movies and for us to be moving back and forth creatively. And I think that was a huge, very unique, creative sort of opportunity that you don't often have in storytelling."

The phrasing "an opportunity you don't often have" is correct, as "Infinity War" and "Endgame" were the product of a decade-long story told through more than 20 films. The build-up to those final two films in what would later be dubbed "The Infinity Saga" is a once-in-a-lifetime cinematic event that has yet to be replicated. While the process may have been harrowing for the Russos and something they would not be quick to do again, at least it was creatively rewarding.

A Delicate Balancing Act

Joe Russo described what a delicate balance the duo had to achieve while filming, keeping every story beat in mind:

"Yeah, I mean, the Star Lord/Thor stuff was really a product of improvisation on set. And really that was, you know, riding a giant bucking bronco for three years, those two movies, because we're constantly trying to stay on top of all the different story elements at all times. 'Well, if we pull this thread, then in this movie over here, we have to pull that thread.' And so it was a very delicate calibration, really unique experience from a storytelling standpoint, from a filmmaking standpoint. And one that we really cherished, but as Anth said, certainly took a physical toll."

"Infinity War" and "Endgame" would use the charm and novelty of characters meeting for the first time, leading to crowd-pleasing moments that also impacted the story. While Thor and Star-Lord's first meeting played for laughs, it also had story implications that would roll over into the rest of "Infinity War" and "Endgame."

The Russos had their work cut out when working on the two "Avengers" films. The process had implications like no other blockbuster at the time, allowing for new character dynamics at the cost of creating a ripple effect through the overarching story of the two massive films. Thankfully, the directors ended up pulling it off, providing a satisfying conclusion to "The Infinity Saga," albeit at the cost of great physical and mental stress.

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