How 'Avengers: Infinity War' Writers Crafted Its Ambitious Ending

Christopher Markus and Stephen McFeely look back at Marvel Studios' biggest conclusion ever: "The question was, 'How do you get there?'"
Courtesy of Walt Disney Studios Motion Pictures

[This story contains spoilers for Avengers: Infinity War]

Avengers: Infinity War is unlike any Marvel Studios film before it.

In addition to combining more heroes than ever, screenwriters Christopher Markus and Stephen McFeely managed to give audiences the most surprising conclusion in Marvel movie history, a move that has paid off in critical acclaim and box-office success. The third Avengers film enjoyed the top opening weekend of all time at the U.S. box office with $258 million, and has fans already ready to line up for 2019's Avengers 4, which will once again be written by Markus and McFeely and directed by the Russo brothers. For the final moments of the film, the screenwriting duo took inspiration from the acclaimed Infinity Gauntlet comics by Jim Starlin.

To reiterate the warning above, there are spoilers below for Avengers: Infinity War.

Markus and McFeely's ambitious script sees Thanos (Josh Brolin) succeed in his quest to acquire all six Infinity Stones. With a snap of his fingers, he eliminates half of the life in the universe, a move Marvel Studios president Kevin Feige told the screenwriters not to shy away from.

"From the very beginning, Kevin said, 'Don't be afraid of that move. It's OK to go there, and let's go there,' " McFeely tells Heat Vision.

In Starlin's 1991 series The Infinity Gauntlet, Thanos' finger snap comes much earlier — in the first issue of the series — and it wasn't a given that this moment would happen at the end of the Infinity War movie.

"The question was, 'How do you get there? How do you bring the most story and emotion and pathos?' And was it going to be where it was? Do you do it at the end of the movie? Do you do it at some other spot?" says McFeely.

While the ending is the biggest cliffhanger in Marvel Studios history, the screenwriters noted that they wanted to provide closure in the sense that audiences should know that, yes, Thanos does complete his plan in this film.

"There are still questions: What are [The Avengers] going to do?, and all those sorts of things," says Markus. "But if you had stopped it before he snapped his fingers, or with four stones, that really is just a pause button. That really is just going, 'What's he going to do?' 'Will your hero stop dangling from the cliff?' And we wanted to put a much more definitive 'Yes, this happens. Deal with it,' tone at the end of it, rather than jerk you around."

In a conversation with Heat Vision, the screenwriting duo — known for penning 2011's Captain America: The First Avenger, 2014's The Winter Soldier, 2016's Civil War and 2019's Avengers 4 — also explains why Steve Rogers (Chris Evans) wasn't in this film as much as you'd think and where Hawkeye (Jeremy Renner) and Ant-Man (Paul Rudd) were all this time.  

With so many characters in play, were there any that were hard to crack as writers?  

Markus: Some of the people, when you weigh up who you are seeing, seem to take a little bit of a backseat in this one. When we did crack them, what we realized was they had far more potential in the movie coming next year, just in terms of how their character would be tested by the story. I'm not telling you what the story is. I will say there is less Steve Rogers and Natasha (Scarlett Johansson) than you might expect in this movie [Infinity War]. Because they are such hard-bitten people, when a threat comes, they stand there and they take the threat. They don't crack. They don't whimper. They don't start talking about all their failed opportunities. So, there isn't that much to explore, especially when you don't have a lot of time. But there's a lot later.

McFeely: We cracked them both [Infinity War and Avengers 4] together, so we had to give ourselves permission to say that some people are going to get more in the next movie.

People are very interested in Hawkeye and Ant-Man's whereabouts during Infinity War. Why didn't they appear?

McFeely: When we get to this time next year, all will become clear. Ant-Man clearly had a specific requirement, which is he had an entire movie [July's Ant-Man and The Wasp] that is going to come between these two movies. Same thing with Captain Marvel, by the way. We looked at that as an opportunity, not as some sort of backbend we had to do.

Markus: Also, Ant-Man the franchise is very light-hearted. It's fun. It maybe even skews younger. If we were to put Ant-Man in this extremely heavy movie, and then have to say to the guys who are making the Ant-Man movie, "Yeah, he went through hell, but now go ahead and have your little romp and we'll pick it up afterwards," that's why we have to really sort of manage your interconnections and go, "Let's go and hold off so you can enjoy that without feeling a bad taste in your mouth."

Director Scott Derrickson did a great job introducing Doctor Strange in his solo movie, and you were able to take the ball and run with it. I was pleasantly surprised by how much Strange was in this. Was he a challenge to get right?

McFeely: We were surprised he popped so much. You always worry when you put somebody next to Robert Downey Jr., they are going to be the straight man, right? To a degree that's OK, but we wanted him to get his licks in. But also, he ends up being in a movie with such peril, he ends up being the reasonable adult in the room. I think a lot of audience members look to him and go, "Oh, it's going to be OK, Doctor Strange is here. He's got a handle on this."

Markus: He's got the widest perspective available, so it's like, "Thank God, somebody gets it." His place in all of this solidified when we got to the line, "If it comes down to the Time Stone, you [Tony Stark] or the kid [Spider-Man], I won't hesitate to let either one of you die." This is a person with responsibilities so far beyond heroism even that he becomes a fascinating addition.

There's a flashback with Gamora as a kid. That's the scene where I understand Thanos and his compassion. How did you craft that?

McFeely: In many ways, this is Thanos' hero's journey. So, we wanted him to be a rich character. He's basically the protagonist of the movie. We've been saying that, and when people see it, they will realize that's actually legit. Part of that is the things that means the most to him. We wanted to show that. It wasn't just power; it wasn't just an ideal; it was people.

While the Thanos stuff is emotional, the Peter Parker death is maybe the most emotional scene. What was the key to that?

McFeely: It was Tom Holland. He crushes that.

For more from Markus and McFeely, check out part one of our interview here, where they discuss working with Guardians of the Galaxy director James Gunn on tone, and tease why Avengers 4 is "bigger" and "better" than Infinity War.