Avengers Endgame truly reached the peak of the MCU fandom with many iconic scenes. One of the most touching scenes in the film comes towards its climax when Tony Stark aka Iron Man snaps his fingers and eradicates Thanos. In doing so Robert Downey Jr says, "I am Iron Man." This one line immediately resonated with many fans. However Avengers Endgame co-writers have now revealed that the original script of the film did not even contain the I am Iron Man line.
Writer Christopher Markus revealed saying, "Because Robert, to his credit – and it’s why Tony Stark has become so iconic – loves to undercut the drama sometimes with a non-sequitur or something. So we tried a few of those and it was like, ‘Really? We’re building up to that?’ That’s why the more serious ‘I am Iron Man’ was a reshoot, because we had a lot of zags. A creative person’s natural instinct is to not give you what you want. To go, ‘Eh, we’re going to do [something else].’ And it takes a while to get to the simpler version of, ‘No, you should do exactly what you think you’re going to do there.’ That’s what hits.”
Avengers Endgame editor Jeff Ford also spoke about the many improvs that Robert Downey Jr did. Ford said, "Robert did a ton of improvs, some of them were funny, some of them were silly, some of them were goofy. But that’s his process to find it. We knew that we were never going to use a silly one, but he goes through that to find rhythms, and as an actor, he’s brilliant at exploring that. The Russos gave him a camera and let it run on him, and let him do a bunch of different things. So we did that and we tried a few of them. Some of them were obscene."
While no one knows the future of Iron Man in the upcoming future MCU films one thing is for clear, Robert Downey Jr has made a forever mark in Marvel films.