On the day Avengers: Endgame officially arrived in theaters -- and hours before it would go on to become the film with the highest grossing opening weekend of all time -- Fandango sat down for a lengthy chat with Avengers: Endgame writers Christopher Markus and Stephen McFeely to answer a bunch of the most burning questions we all had walking out of that three-hour rollercoaster of emotions. What's up with the time travel? The deaths? The finale? And what is the current status of the MCU post-Endgame?

Markus and McFeely are very much the unsung heroes of the Marvel Cinematic Universe. They've worked on every Captain America movie (The First Avenger, The Winter Soldier, Civil War), as well as Thor: The Dark World, Avengers: Infinity War and the television show Agent Carter. It is their collaboration with directors Joe and Anthony Russo that truly redefined what these Marvel movies could be. Beginning with The Winter Soldier and continuing through Civil War, Infinity War and eventually Endgame, the foursome crafted an experience for the ages, brilliantly building a connected narrative that fueled some astonishing momentum. By the time we arrived at Avengers: Endgame, it had become one of the most anticipated films of all time. Now, it's become one of the biggest moneymakers, too.

Below, Markus and McFeely talk about how they went about tackling one of the most significant and talked-about finales in movie history. From the time travel to those major deaths, here's how it all came to be.


Fandango: Let's start with the time travel. What was your approach?

Stephen McFeely: Okay, so we always like writing ourselves into corners, and we had issues early when we came up with this idea to sort of seal The Snap in amber, right? To make it permanent when Thanos destroys the stones. And then we killed Thanos, right? We just really couldn't write ourselves into a bigger corner. How do you solve that, assuming you want your movie to bring people back? So Kevin is a big fan of time travel. He's a big fan of sort of big season-ending two-parters, that kind of stuff. And we knew we wanted to play with time and we knew that we felt that the MCU had kind of earned it in that we had the material to go root around in the past if we wanted to. And the stones are in the past, and when we hit on that idea that the second act would be a time heist through Marvel's own movies we were kind of got giddy about that.

So, then, we had to decide what kind of time travel rules we were using. We brought in a couple of physicists who, to a man, said, "I'm glad you brought me in, because I've always wanted to talk to people from Hollywood to say that you know I love Back to the Future as much as the next person, but we don't think that's how it would work." Which was also helpful for us because as you can imagine, every time we went back to one of ... you know we have six different time heists in three or four different periods ... if every time you went back you created a new Biff's Casino, for want of a better term, right? Another crack in the version of your timeline? We would never get out of the second act.

So for us the strongest thing we could do, and the most helpful thing we could do, is to operate under some kind of branch reality, so that the things that have already happened ... which is what ... again, it's time travel which is humanly impossible, but a number of physicists had told us it's much more likely we would operate in a branch reality than a singular timeline. So that's the floor for the time travel conversation.

Christopher Markus: And when the subject of a "time machine" first came up we all kind of groaned, though, because it does seem like a get-out-of-jail free card. "Well Tony can invent a time machine" is about as arbitrary and easy as you could get. But it was when ... you know, we already weren't going to use Scott Lang in Infinity War, because we didn't want to change the Ant-Man and Wasp movie too much. You know, we only had an influence over the end tag. And so we wanted to allow that to be a freestanding movie, so we couldn't entangle him in Infinity War. We knew we had access to him for the second, and that ... again, according to Theoretical Physicists, time would be completely different within the Quantum Realm. That it is a totally different construct within there. So we had a character we were going to bring in who was coming out of a world in which time was different, and suddenly it seemed like there was a very MCU-organic way to build a time machine that didn't feel like bulls*it.

Fandango: How did you go about picking the MCU moments they went back to? And were there certain moments you had in there originally, but got rid of?

Stephen McFeely: Yeah, our first draft was a version where Tony and Thor go to Asgard, because I like the idea of Tony going, like, in theory going to Asgard and seeing science versus magic, and stuff like that. And then he fought Heimdall, who could of course see him even though Tony had an invisible stealth suit on or something. And we did that because there is, in Dark World, to get technical about it, during that time when the Reality Stone is there, the Space Stone is also in the vault. So at the end of Dark World you might remember that Volstagg and Sif go to the Collector and pass off the Reality Stone because they don't want to keep two stones in one place. So that was one attempt at it, and I think Joe Russo read it and he goes, "Why aren't we going to Avengers? It's only the most exciting movie." And so we went yep, let's do that.

Christopher Markus: We were initially hesitant to go back to the first Avengers [movie] because it seemed like we were just pandering and playing the greatest hits. You like that movie? We're going right back to that movie! And then it really became clear we were overthinking it in terms of what would be the most fun.


Fandango: Were there any other moments you guys toyed around with going to? 

Christopher Markus: Yeah I think there was a draft where the Space Stone, the Cosmic Cube, the Tesseract, was retrieved from the Triskelion-

Stephen McFeely: No, that was the Mind Stone.

Christopher Markus: Oh...

Stephen McFeely: The Tesseract was always in Asgard. In Central Park.

Christopher Markus: Oh that's true, that's true.

Stephen McFeely: So it was the Mind Stone.

Christopher Markus: It was the Mind Stone, but I think that may have been the genesis of the elevator redo scene, because it would have had Steve in the actual elevator where the Winter Soldier scene took place, and then when we moved it to Stark Tower it was easy enough to transpose the scene without losing it.

Fandango: Well, and Cap is the only one that runs into his older self. Talk about that moment. Was it always just Cap who ran into himself?

Stephen McFeely: No it was always Cap on Cap [because it] seemed like an interesting dynamic. You know Tony is in the same place as Old Tony, we just use it for comedy as opposed to conflict.

Christopher Markus: We may have at one time had Dark World Thor catch sight of Endgame Thor and go, you know, "What the hell happened?" But it got too complex and it distracted from things.

Stephen McFeely: That would have been a third version of Thor in this movie, you know?


Fandango: Speaking of Thor, Thor: Ragnarok feels like it had a significant influence on characters in this film.

Stephen McFeely: I mean, we did all of this before Ragnarok.

Christopher Markus: Yeah, initially we were writing drafts prior to Taika coming onboard. And it was once they got underway and they were off in Australia making the movie and it was clear that they were discovering new facets to Thor, Chris Hemsworth wanted to make sure that this new loosened-up Thor didn't vanish immediately upon returning to the Avengers world. And so he and Taika flew to Atlanta and we had long meetings with them and watched some footage and got a sense of the new Thor tone, and it worked perfectly with where we wanted to go.

Stephen McFeely: At some point when we figured out what we wanted to do, and create Smart Hulk in the second movie, I think Kevin sort of pulled Mark aside and said, "Listen, we're sort of treating these next three movies, Ragnarok, Infinity War, and Endgame, as sort of a longterm three-movie Hulk arc. So be patient because that third one is gonna be great."

So yeah that was always a wrestling match, right? Because we weren't sure when the Smart Hulk transformation was going to happen. So was it meant to be at the end of Infinity War? Was it going to be at the top of Endgame? You know, it was always fluid.


Fandango: One of the most memorable lines in the film is Stark's "I love you, three thousand." Where did that come from?

Christopher Markus: Well much as we'd like to take credit for what is inevitably going to be one of the most memorable lines in MCU history, that is something that Robert and his children actually say to each other, and he brought it from real life onto the set.

Stephen McFeely: The script was, "Love you tons. Love you tons." And now it's, "Love you tons. Love you 3000."


Fandango: Talk about the endings for Cap and Iron Man. Did you guys always have this idea that Cap would go back and grow old, and Tony would die? 

Stephen McFeely: We're very excited by this. If you look back at the MCU, that Steve and Tony have been on different paths towards becoming the fullest versions of themselves. And Steve's arc is about trying to find some personal life, you know? Like he's been a man for others for so long, when does he get to be a man for himself? And how is that not selfish? How is that just earned?

And Tony goes from sort of self-interested playboy to a man for others. A man willing to lay his life down. And so they sort of cross in the middle in Civil War, and the natural end of those arcs seemed to be Tony laying down his life, you know, flying over the wire as it were, and Steve going and getting a life. So where we hit upon it was in order to become their best selves, Steve had to find a life, and Tony had to lose his.

Fandango: So people are asking... Does this mean an old Captain America was hanging out this whole time while another Captain America was saving the day?

Christopher Markus: That is our theory. We are not experts on time travel, but the Ancient One specifically states that when you take an Infinity Stone out of a timeline it creates a new timeline. So Steve going back and just being there would not create a new timeline. So I reject the "Steve is in an alternate reality" theory.

I do believe that there is simply a period in world history from about '48 to now where there are two Steve Rogers. And anyway, for a large chunk of that one of them is frozen in ice. So it's not like they'd be running into each other.


Fandango: Tony Stark didn't run into his younger self, but he did run into his younger father. How did that scene come about?

Stephen McFeely: We knew that we wanted a sort of no-going-back hiccup to happen during at least one of the time-heist journeys. So when we knew that Henry Pim and Howard Stark had sort of a friction relationship back in the day, and Peggy Carter helped found S.H.I.E.L.D, and that there was undoubtedly a time when they were all together, if you decided that they were out of Pim Particles and had only one way to go, that was pretty delightful. And it was going to be able to hit a bunch of buttons. Remember, all the journeys sort of allow each character to deal with emotional stuff, and obviously Tony always had daddy issues.

Christopher Markus: But it just worked out so, so nicely that he could go back to when his mother was pregnant with him, now that he is a father. I mean it's a very strange setup. He is a father and older than his own father, while talking to his father, whose wife is pregnant with him. Once you realize that you have the opportunity to do that, there's no way you're not going to do that.


Fandango: You have a bunch of people that come back into this movie. For example, Natalie Portman was a surprise. Was she baked into the script from the very beginning? Or did that happen late in the game?

Stephen McFeely: Yes. It was very hard to find a way to not do that, seeing as one of the Infinity Stones is inside her for primarily the only time we've ever seen it. It's literally inside her arm, so there weren't too many variations that didn't have Natalie Portman in them. There were longer ones, but they ... you know you wound up before Thor and his mother was so rich and so on point in terms of what he needed to learn that in already a three-hour movie we couldn't really have a long scene between, say, Rocket and Jane, because, again, it's drifting off of the character stories that we wanted to tell.

Fandango: Black Widow is another casualty in the movie. Why did you choose her to sacrifice herself instead of Hawkeye?

Stephen McFeely: Well, you know the rules of the Soul Stone. So, of our group, I guess you could make an argument you could send Smart Hulk and Natasha. But we've always felt that the platonic love between Natasha and Clint is pretty evergreen. And when they get to that moment and he now has so much red in his ledger... we liked this idea that she was the last one on the wall, right? That she had found her purpose and her family in Avengers and could not give that up, and would not, much like Steve Rogers ... or I should say like an older Steve Rogers. This Steve Rogers is despairing in a way, right? Maybe we should stop, but she won't. So we've always thought that the most perfect conclusion to her arc would be to die for her new family, or to sacrifice greatly for her new family. We toyed with not doing that, and we had another version, and several women on the crew said, "Don't you dare take that choice away from her. The heroic thing is for Natasha to do it, not for Hawkeye to do it." And so we listened to that. Yeah.


Fandango: One thing that we don't know about the Soul Stone is what happens when you bring back the Soul Stone? Cap bringing back all of these Stones, how do you feel like that could potentially influence the future of the MCU?

Stephen McFeely: It seems like a question for another time.

Christopher Markus: And for another writer. But all I know is when we kill somebody, except with a Snap, they're dead.


Fandango: The Snap did bring back a lot of our favorite characters. Loki, is he kicking around somewhere? And what about Vision?

Christopher Markus: No, I mean we only brought back the people who were effectively disintegrated by the Snap at the end of Infinity War. Anybody who died over the course of the movie through neck-snapping or stabbing or being thrown off a cliff or having a Mind Stone torn out of their head stayed dead.


Fandango: That final battle is so epic in scale. How do you even approach writing something like that?

Christopher Markus: Approach it by writing it about ten thousand times

Stephen McFeely: Try to create a central spine, right? And certainly that thing was longer and had more reunions and all that kind of stuff, and it just got bloated. But in essence we said to ourselves, alright, they all come back. They have an early wave of success. Thanos then fights back. You dollop in a few reunions that you need, Tony and Peter being kind of the most important, and then very quickly I got them back on the field and try to create this spine of will they or won't they?

So we called it the "flee-flicker," mostly because most of us don't know much about sports. But the idea that the gauntlet would get passed from hero to hero in a desperate attempt to get it through a throng of villains to the goal line. And then even then the goal line is destroyed and now you're in this scramble for who's going to get the Stones.

Christopher Markus: And that was another happy day in the conference room where we realized that the ridiculous van from Ant-Man that we had at the beginning of the movie could come back and be of use in the third act. What we didn't want to do was bend over backwards to have Thanos have destroyed the whole compound except the one machine, and the van seemed like a nice save.


Fandango: Falcon gets Cap's shield at the end, so would you now consider him to be the new Captain America? 

Stephen McFeely: As far as we know, yeah.

Christopher Markus: Certainly seems like it to me.


Fandango: Iron Man is dead, but do you feel like there is a world where an Iron Character will live on and take up that mantle? Is it Pepper?

Christopher Markus: Ooh, well there certainly are a bunch of people with suits who are alive.

Stephen McFeely: But we don't know what they've got planned.

Christopher Markus: Yeah, there are no Iron Teen scripts as far as I know. 

Fandango: Talk about where we are now. It's five years later -- for example, how is this impacting Spider-Man? Did some of his friends graduate and others didn't?

Stephen McFeely: If I were writing and directing that movie, I would probably address it in some way. But I don't know how they'll do that.

Christopher Markus: If only there were a movie coming out in a few months that would answer your question...


Fandango: Okay, so Spider-Man aside, how would you describe the state of the MCU at the end of Endgame?

Stephen McFeely: Oh for sure, it's the Marvel Universe as far as we know is five years ahead of where it was at the end of Infinity War. Full stop. Period. Yes. It is a big swing, it's complicated, it means that half of the planet basically has either lost five years or lived through a terrible five years. Yes, that's the MCU going forward.


Fandango: Do you have a personal favorite moment from the film? Something you've been waiting a long time to put in an MCU movie?

Christopher Markus: Certainly seeing Steve reunited with Peggy at the end is, you know, that is literally full circle with our time in the MCU. You know, we did First Avenger, we did the Agent Carter show in the middle, and now we got them back together at the end, and it feels right.


Fandango: Do you think there's a world where we see the adventures of Captain and Peggy either on the big or small screen?

Christopher Markus: Possibly. I think maybe all I did was Steve was a stay-at-home dad and Peggy went to work at S.H.I.E.L.D. I don't know that there were any adventures.


Fandango: What about all these Fox characters coming over? If you were offered to make a movie about any of those characters, who would you choose?

Stephen McFeely: [to Chris]: Well, you're a Cyclops fan.

Christopher Markus: Yeah I've always wanted to see Cyclops done with some respect. Feel he's gotten a raw deal.

Fandango: How do the events of this film influence those Disney+ shows? You have the Loki show, a Hawkeye show, and a Wanda/Vision show, too. Are you guys involved in sort of setting up the pieces for those shows?

Christopher Markus: No. All I know is that I believe that they take the events of this movie into full consideration. They're not on a side continuum.


Fandango: So they exist in a world where the events of this film have taken place?

Christopher Markus: I believe so, yes.


Fandango: And, lastly... is Thor part of the Guardians now?

Christopher Markus: Ask Peter Quill.

Stephen McFeely: Yeah, you might have to ask James [Gunn] or Quill.


Avengers: Endgame is in theaters now. Get your tickets right here at Fandango.