Not to put too fine a point on it, but “Avengers: Infinity War” is, well, big. It had to be in order to pull the various strands of a sprawling cinematic universe together. The question is: Can this on-screen world get even bigger?

“We never think in terms of ‘big,'” co-director Joe Russo says. “We think in terms of story, and a culmination story of 18 films and a bunch of successful franchises is of a certain scale … But that’s not a mandate you can follow as a filmmaker. That’s a path that leads to nowhere.”

Fair enough, but just given what’s on the table in terms of Marvel’s television exploits (shows like “Daredevil” and “The Punisher” on Netflix, or “Marvel’s Agents of S.H.I.E.L.D.” on ABC), there was already plenty more to work with.

“We made the briefest consideration of [including TV characters in ‘Infinity War’],” co-director Anthony Russo says. “When we’re alone in a room with [screenwriters Christopher] Markus and [Stephen] McFeely, we consider every idea. We like thinking of everything. But it seemed like the story that had been told within the movies was so specific and elaborate already that once we started working through the story, we knew we had our hands full just with this set of characters and narratives.”

Nevertheless, for a company that builds things out in phases, there is always the next phase to consider. Given Disney’s ongoing effort to acquire Fox’s film assets, Marvel Studios’ movie horizons could soon broaden overnight. Media and fans alike have speculated endlessly about what the addition of properties like the X-Men and Fantastic Four could mean to the universe painstakingly constructed over the last 10 years. A character like Silver Surfer, for example, would have felt right at home in “Infinity War” (Indeed, he is a fixture of the “Infinity Gauntlet” comic book series that served as source material for the new film).

“I think just as far as where that specific deal is at right now, it’s not at the point where we can start working with those characters on a creative level yet,” Anthony Russo says. “We’d love to and hopefully it will all work out some day, but it’s not in the time frame of these movies that we’re making right now.”

The brothers stirred excitement recently by merely breathing the two words “Secret Wars,” invoking the 1984 series that captured the hearts of fans the world over. The ultimate Marvel mash-up at the time, writer Jim Shooter’s story amassed all of the label’s heroes from the Avengers, Fantastic Four, X-Men, and more for a galactic tale that spawned a sequel the very next year. “That was probably the most important book to me growing up,” Joe Russo says.

Whether they’ll get a chance to tinker with those characters or not, we’ll have to wait and see. But the Russos’ intention is to stick with Marvel after the next “Avengers” film finally puts a bow on this decade’s build. And if a shiny new set of toys does arrive, they aren’t likely to be blinded by the prospects.

“If you ever think in terms of outdoing, you tend to trip over your own two feet,” Joe Russo says. “You really have to commit to, ‘What is the narrative here? What story are we trying to tell? What is required to tell that story?'”

For more from the Russos on their latest Marvel blockbuster, check out the latest episode of Variety and iHeartRadio’s “Playback” podcast.

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