Warning: This post contains spoilers for "Avengers: Endgame."

The "Avengers: Endgame" directors Joe and Anthony Russo talked to Business Insider about the pressure of bringing this era of the Marvel Cinematic Universe to a satisfying conclusion.

The Russos answered burning time-travel questions and addressed both Loki and Gamora's fates at the end of the movie.

While the filmmakers say they're done with the MCU for now, they acknowledged what could bring them out of Marvel retirement.

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Warning: This post contains spoilers for "Avengers: Endgame."

Seven years ago, the filmmaking brothers Joe and Anthony Russo were hired to direct "Captain America: The Winter Soldier" after they had made their name in TV sitcoms like "Arrested Development" and "Community."

"The Winter Soldier" opened in 2014 to rave reviews (it has a 90% Rotten Tomatoes critic score) and decent box-office returns (it grossed $714 million worldwide), solidifying the Russos as the Marvel Cinematic Universe's future power players.

Read more: The Marvel Cinematic Universe will enter an uncertain era after 'Avengers: Endgame,' but experts see a path for it to dominate another decade of pop culture

Now, "Avengers: Endgame," the culmination of not only their four Marvel movies but the entirety of the MCU up to this point, is shattering box-office records at an unprecedented level.

The Russos talked to Business Insider last week about the pressure of bringing this era of the franchise — the biggest one of all time at over $19 billion worldwide over 22 movies — to a satisfying conclusion. They also addressed the fates of key characters like Captain America, Gamora, and even Loki, and what could bring them back to the MCU.

"Avengers: Endgame." Marvel Studios/Disney

This interview was conducted on Wednesday, May 1. It has been lightly edited for length and clarity.

Travis Clark: Now that the movie is out, what's running through your mind? Is it a big weight off your shoulders?

Joe Russo: It's a big weight off our shoulders, without question. We did four of these in seven years, and there were bigger stakes for each one that we did. The budgets went higher and the complexity went higher and the degree of difficulty gets higher with each one.

Clark: Was that daunting?

Joe: It's daunting only in the pressure that you put on yourself. We're good at blocking out pressure from the outside world because it doesn't add a lot of value to what we're doing. We always just try to focus on telling the best story. Certainly, once you're done and you spend a month promoting the movie before its release, that's when you first think about, "I hope this works." Until then, you're making one of the most expensive movies ever made and that involves a lot of decisions being made every day, so your mind is fairly occupied.

Anthony Russo: It is a massive change for us because seven years ago exactly we were hired by Marvel, and from that moment on we were hurtling toward a production date and then a release date.

Read more: 'Avengers: Endgame' raises questions about the future of the Marvel Cinematic Universe, but it gives plenty of clues

Clark: Were the high stakes the most intimidating part of making this movie?

Anthony: The stakes and the schedule. These are very complex movies, and they're logistically complicated.

Joe: I would argue that the stakes were even less significant than the physical toll. That's the thing that you stare down every day. The hours are intense. You're shooting for a year straight. We were working seven days a week, on average 15 hours a day, for a year.

Clark: Especially for that final battle, right?

Joe: For sure. Those are a grind. They're hard.

Clark: What were some of the intricacies of that?

Joe: When you're working with action, it's hard on the crew, it's hard on the cast, it's hard on us as directors. It's physical, it's people taking fake punches, but they can get hit sometimes. You have to be careful with the set. That's a high-pressure situation during action sequences. There's explosions and dangerous things happening all the time on set, but you have to control the chaos. If you're doing that day in and day out for a few months, the tension is always high.

Chris Hemsworth as Thor. Marvel Studios

Clark: Did you ever have a scare on set, like something go wrong?

Anthony: Never with the cast, but Chris Hemsworth did have to wear a bodysuit for that [Thor] role. We had to toggle back and forth. While we were shooting "Endgame" where he was heavier we had to do some pickup shots for "Infinity War," so he would have to go back and forth between those two looks. So he had to wear a bodysuit, and it was quite heavy. That suit started to wear on his back, which was scary when you have someone who has to be so physical.

We were shooting in Atlanta, so exterior stuff in Atlanta in the summer was brutal. The actors' costumes don't breathe very well.

But I wanted to make clear, though, the stakes for us were the opportunity to work with the material. It's special for Joe and I. We know we have a huge passion for the material, and we know it's something we're extremely motivated to do and something we want to spend our time doing. Whether or not it works for audiences is a separate question from that and something we can't control.

Read more: How 'Avengers: Endgame' changes these 5 coming Marvel movies and TV shows

Clark: So you're coming at it as both fans and filmmakers. Is that hard to distinguish?

Joe: I think that it's the fan in us that fuels the filmmaking choices. We've been inspired by these mythologies since we were children and have an emotional connection to it and understand it on a deep level. I don't think we'd be where we are without the fan in us.

Anthony: And that's been the whole key for us. Because we have that passion for the material, we never need to question ourselves. We always know we're servicing the fan in ourselves, and that's the only fan we can service. Every fan in the universe has different opinions than we have. Fandom doesn't speak with one voice.

Jeremy Renner as Hawkeye. Marvel Studios

Clark: In The New York Times, [the "Endgame" screenwriters] Christopher Marcus and Stephen McFeely said that it was your idea, Joe, to open the movie with Hawkeye losing his family. Why was that the right thing to do?

Joe: We were originally going to include that at the end of "Infinity War." Hawkeye wasn't going to be in the film, and then at the end when Thanos snaps his fingers, we were going to cut to black and then come up on a family picnic at [Clint] Barton's (Hawkeye's) house. We wanted the audience to be confused. "Why are we here, what am I watching?" And then after Barton's family slowly disappeared we'd cut back to Bucky. We tried it, but we found that it was too jarring of a concept. So I thought, why don't we remove it from the body of this movie and move it to open the next movie. It's a great way after a year to remind you of the pain that everyone was feeling.

Anthony: It ended up being appropriate because "Endgame" is so dependent on moving forward from that moment.

Clark: And then after the opening of the movie, after they kill Thanos, it jumps five years. What made five years an appropriate length?

Joe: We wanted something that allowed them to change enough. We needed enough time for them to process their grief that it would alter them as people.

Anthony: They were past the immediate grieving period.

Joe: They accepted it and made choices about how they were going to proceed with their future, and that changes people. Clearly, Banner has changed dramatically.

Anthony: It gave Tony enough time to have a daughter he can interact with.

Joe: Thor became increasingly depressed and isolated. So one year wouldn't have allowed for quite the effect and five makes it feel more permanent to the audience.

Read more: There are 6 Marvel movies in the works for after 'Avengers: Endgame' — here are all the details

Clark: Yeah, there were gasps in the audience when that ["five years later"] title card came up on screen.

Joe: Our mission is to always surprise the audience. When we sit in the writer's room, we try to follow a path of logic together. Thanos snapped, half of life disappeared, and if you're a hero, how to do you proceed with that? You go through the stages of grief. You get angry and you go after him. What happens when you go after him? Well, he's a really smart villain so he [destroyed] the stones so that nobody else could ever use them. Now what happens? Well, the angriest among you, the one who's suppressing his guilt about the final confrontation he had with Thanos in "Infinity War," cuts his head off. Now what happens? You just keep tracking forward. So what if we just jump in time and found them all in a fractured, dystopian future?

Anthony: The thing that excited us most about that was, to start the movie at that moment, when Thanos had snapped, and then blow way past that moment and move on to something else. It just seemed exciting to us.

Clark: You mentioned a dystopian future, and that shows that Thanos' plan was flawed.

Joe: Well, Thanos is crazy [laughs].

Clark: Well, yes, but his whole deal was that he thought life would thrive, but that obviously doesn't happen on Earth. Is that something you wanted to convey?

Joe: Thanos is an egomaniac. He was rejected in his youth when he presented a solution to his home planet and he lost it and probably lost a lot of people he cared about. So years later, he has processed his grief in a way that has convinced him that this is a really good idea.

He's smart enough to know logically that it's like resetting planets like Earth back 50 years. But I think his hope was that the pain of what he had done would teach them to appreciate the resources moving forward. And by the end of the movie, he gets to the point where he's like, "I should have just wiped it all out and started over."

Anthony: Because people can't get past their memories.

Chris Evans as Captain America. Marvel Studios

Clark: Was there ever a discussion about giving Captain America's shield to Bucky instead of Sam, and why not Bucky?

Joe: We definitely would sit around and talk about what made the best story moving forward, and Sam just always felt like the right recipient. After all, Bucky is damaged.

Anthony: And Sam seemed to most share [Steve Rogers'] qualities. When they first met, the bond between those two characters just spoke to a symmetry in their moral nature.

Clark: What made Cap finally worthy of Thor's hammer? Was there a specific instance, because in "Avengers: Age of Ultron," he nudges it, but can't quite pick it up.

Joe: I think in "Age of Ultron" he may have not picked up the hammer in order to not embarrass Thor.

Anthony: That's the way we think of it.

Read more: We made a timeline showing the entire history of the Marvel Cinematic Universe leading up to 'Avengers: Endgame'

Clark: At the end, when Cap brings the stones back in time, does he correct all the timelines that got screwed up? Is there a past Loki still out there?

Joe: The intent was that he was going to correct the past timelines at the point that the stones left.

Loki, when he teleports away with the Time Stone, would create his own timeline. It gets very complicated, but it would be impossible for [Cap] to rectify the timeline unless he found Loki. The minute that Loki does something as dramatic as take the Space Stone, he creates a branched reality.

Anthony: We're dealing with this idea of multiverses and branched realities, so there are many realities.

Clark: So by that logic, Cap basically created a new timeline for himself when he went back?

Joe: Correct, so he would have to come back to this timeline in order to hand off the shield.

Anthony: There's a question of, how did this separate timeline Cap come to reappear in this timeline and why?

Clark: And that's a story for another day?

Joe: [laughs] Correct.

"Guardians of the Galaxy." Marvel Studios

Clark: At the end, Peter Quill (Star-Lord) is looking at a computer screen for Gamora. I assume she didn't get dusted? So obviously they're looking for her. Can you answer just generally where she went? We didn't see her leave.

Joe: We don't know whether she was dusted or whether she survived. That's probably a question that "Guardians [3]" will answer.

Anthony: Quill doesn't know either.

Joe: I'm sure future films will answer that question.

Clark: That's up to James Gunn, I guess.

Anthony: [laughs] Exactly, we've done our job.

Clark: Are there any Fox characters you wish you could have used in this movie, hypothetically?

Joe: We love all the Fox characters, but there were so many characters in this film. I don't know if we could have handled adding any more characters, especially characters that weren't developed in the Marvel Cinematic Universe. But I'd love to in the future.

Clark: Have you heard of any Fox conversations?

Joe: We don't know what [Marvel Studios president] Kevin [Feige]'s plans are. He's been very specific about just ending the Infinity Saga. But Fantastic Four needs a definitive movie at some point.

Anthony: There's a whole layer of complexity to the whole equation that had to play out first. The business issue was announced and achieved first [the Disney-Fox merger]. Now the creative work begins.

Read more: Every Marvel Cinematic Universe movie, ranked from worst to best

Clark: Is there a backstory behind "America's ass"?

Joe: [laughs] No, we were just looking for a good joke about his suit from "Avengers."

Clark: Yeah, his suit has really evolved over the years.

Joe: [laughs] Yeah, we were looking for something that didn't make too much fun of the suit but gave the audience a good laugh.

Clark: A more serious question to end on: You guys have said you're done with Marvel for now, but is there anything that would bring you back to this franchise? Any movie, any Disney Plus show, anything?

Anthony: We don't know what that is yet. We love Marvel, we have the most amazing working relationship with them, and we're very close with them. Maybe there will be an idea that comes up in the future, but there is none now.

One of the great creative upsides of "Endgame" for Joe and I was this was the first time since we started on "Captain America: The Winter Soldier" seven years ago that we weren't thinking about the future of the MCU at all. Our job on this movie was to bring things to a satisfying conclusion. I think that was really creatively liberating for us. We really thank and respect Kevin for giving us that space. It's part of why he's a genius producer.

Clark: But if the right thing came up, you'd think about it?

Anthony: For sure.

Joe: Absolutely. It's just about finding the right story that inspires us. That's why we get out of bed every day [laughs].

Clark: Any particular characters that would do that?

Joe: I mean, I love Ben Grimm from the Fantastic Four. Doctor Doom was always one of my favorite villains. Wolverine, but I think he's got to be set aside for a little while.

Clark: Yeah, it's hard to top Hugh Jackman.

Anthony: [laughs] Yeah, that was an amazing run.

Have a tip about Marvel, Disney, or anything else? Email the author at tclark@businessinsider.com