Russo Brothers Say Jon Favreau Argued Against Killing Iron Man in Avengers: Endgame

"I am Iron Man." Those are the last words of Tony Stark (Robert Downey Jr.) in Iron Man and Avengers: Endgame, and as told by four-time Marvel directors Anthony and Joe Russo, "You do not want to f— up Tony Stark's last line." A snap of Iron Man's armored fingers follows those four words, the cosmic power of the Infinity Stones erasing the "inevitable" Thanos (Josh Brolin) and saving the universe — at the cost of Stark's life. But executive producer Jon Favreau, who helmed the first two Iron Man movies and helped launch the Marvel Cinematic Universe, weighed whether killing off Iron Man would "devastate" moviegoers. 

"It's probably the most pressure we've ever had in trying to come up with a line with [screenwriters Christopher] Markus and [Stephen] McFeely on any of these movies," Joe Russo told Vanity Fair. "You do not want to f—up Tony Stark's last line." 

Added Anthony, "Part of the pressure came from Jon Favreau, who called us up after he read the script and said to us, 'Are you guys really going to kill Iron Man?'" 

Joe recalled "pacing on the corner of a stage on the phone with Favreau trying to talk him off a ledge." 

"He's like, 'You can't do this, it's gonna devastate people. You don't want them walking out of the theater and into traffic,'" he said. "We did it anyway." 

"We did it anyway, and to Jon's credit, he hadn't stepped through the process in the way that we had," Anthony noted, saying the brothers "would have had the same reaction" if they hadn't directed the back-to-back Avengers movies. 

After the disassembled Avengers failed to stop Thanos from wielding the six Infinity Stones and snapping half of all life in the universe out of existence, Joe said, "We felt that we had earned the arc that would feel redemptive and emotional and uplifting and hopeful, even though [Stark] had sacrificed his life."

Downey improvised "super-smartass" alternate lines, including an "Oh, snap," and an F-bomb lobbed at Thanos.   

"We tried some alternate versions of it, and they were sort of more in the snarky, Tony Stark vein," Joe said. "He wasn't playing it with enough pain of the power of the [Infinity] Stones surging through his body." 

The brothers landed on a version "where he said nothing," Anthony recalled of Stark's final moments, before editor Jeff Ford suggested the callback to 2008's Iron Man

"Our editor, Jeff Ford, who is one of the most amazing filmmakers we've ever collaborated with, edited the first Iron Man movie. So he had been on the journey with the character since the original Jon Favreau-directed Iron Man," Anthony said. Joe added, "He hit play, and Thanos says, 'I am inevitable.' Beat, beat, beat. And Jeff went, 'I am Iron Man.' We were like, 'Stop! What did you just say?!'"

He added: "We called Downey and said, 'You gotta put the suit back on.'" 

Avengers: Endgame is now available to stream on Disney+.