Is Robert Downey Jr. the One True Iron Man?

In a recent interview with Forbes, the co-director of Captain America: Civil War hinted that when Robert Downey Jr. no longer wants to play Tony Stark/Iron Man, the character "might disappear for a while" because Downey would be "almost impossible to replace."

Joe Russo suggested that the only way Downey could be replaced in the role is if a new actor from a younger generation came along to pick up the Iron Man suit after the world has had a long time to forget Downey's performance.

"That would allow another actor to at least have a chance to redefine that character without the enormous spectre of Robert hanging over it," he said.

Tying a superhero character to a single actor over the course of a generation or more would be unusual, if not entirely unprecedented. Spider-Man, who will share the screen with Downey in Captain America: Civil War, has been played by three different actors just since 2002. In the DC universe, the role of Batman has gone to five different actors between Michael Keaton's 1989 version and Ben Affleck's 2016 turn in Batman v Superman: Dawn of Justice. Superman himself has been played by three different actors between 1978 and 2016.

All of these characters, however, had been played by someone else, on TV or in earlier films, before their contemporary incarnations. Iron Man, by contrast, had never appeared in live action film or TV before the character's 2008 feature-film debut, so no one other than Downey has ever played the role. It may just be familiarity that makes Downey seem irreplaceable. It's hard to say if Downey is the best Iron Man when he's the only one who's ever had the chance to be Iron Man.