Tony Stark revealing his true identity at the end of the first Iron Man movie is really what kicked off the Marvel Cinematic Universe. The icing on the cake was the inclusion of legendary heavy metal band Black Sabbath's "Iron Man." Now, one clever MCU fan has brought things full circle with an Avengers: Endgame edit utilizing the classic song and it is almost too perfect. The MCU knows how to use their music and they choose it wisely, but it seems they missed an opportunity here.
The fan edited Endgame scene in question comes towards the conclusion of the movie, right before Tony Stark tricks Thanos and gives him a snap of his own. Thanos says, "I am inevitable," which is when the iconic kick drum and bent guitar notes from Black Sabbath's "Iron Man" start playing. Robert Downey Jr.'s Tony Stark then responds by delivering the now-classic line, "I am Iron Man," before dusting the Mad Titan and his whole army with his own Infinity Gauntlet. By this time, the song has kicked in and all is right in the universe for a brief moment.
Tony Stark sacrificed his life to save the universe in Endgame, which was not really a surprise for MCU fans. However, that doesn't mean they were any less bummed out by the situation. In fact, fans are still sad about the decision to kill off one of the most beloved superheroes of all time. Joe Russo was recently falsely quoted about killing of Stark and made a joke pertaining to the situation on social media. While it was obviously a joke, fans in the social media thread were still pretty broken up about the fact that Iron Man is now dead.
As for the "I am Iron Man" line, that was something that came along late into the creative process. The Russo Brothers were editing the epic movie when the line was suggested and they immediately called Robert Downey Jr. to get him down to the studio to deliver the line. It's a defining point in the movie and the MCU as a whole. Tony Stark isn't going to be there to help get everybody out of a bind from here on out, but he has left behind some pretty amazing technology.
Using Black Sabbath's Iron Man would have taken away from the emotional death of Tony Stark at the conclusion of Endgame, so it's probably a good idea that they didn't include the song, no matter how cool it would have been on the screen. With that being said, Endgame delivers surprises and, for the most part, stays away from the obvious. Using the "Iron Man" song might have been obvious in the context of the movie's storyline, but it sure is epic in the latest fan-made clip. The clip in question originated over at Reddit.