Robert Downey Jr.'s casting as Doctor Doom is explained in a new MCU theory that connects with the confirmation that Tony Stark's death plays a role.

Avengers directors Joe and Anthony Russo are keeping schtum about the plot circumstances surrounding Robert Downey Jr's Doctor Doom role, but they have teased a one-of-a-kind performance from the one-time Iron Man actor.

Anthony Russo was recently asked how they will explain RDJ’s return and his answer was well, mysterious: “We can’t explain that as it’s part of the story,” he said with