Avengers: Endgame | Behind-The-Scenes Preparation for a film adaptation of Jim Starlin’s 1991 The Infinity Gauntlet comic book began with Marvel Studios’ early films, which introduced the Infinity Stones as plot devicesand teased a future storyline with Thanos as the villain. Downey Jr. signed on in June 2013 to reprise his role as Tony Stark / Iron Man, Brolin was cast as Thanos the next May, and many other actors were confirmed to be appearing in the following years. The films were officially