After Avengers: Endgame gave Tony Stark a noble end by selflessly sacrificing himself—definitively closing the book on Robert Downey Jr. in the MCU—fans thought it was over. Marvel President Kevin Feige, however, backtracked on plans to phase RDJ out at San Diego Comic-Con 2024, revealing the former Iron Man actor would return to play Victor Von Doom. His new contract isn't available to the public, although Feige confirmed Downey Jr. would be in both Avengers: Secret Wars and Doomsday. He'll probably have roles in a few other movies, potentially the fourth Spider-Man movie, which coincidentally premieres two months after Avengers: Doomsday.
As for the actor's new role, Victor Von Doom differs quite a bit from Tony Stark. For one, he's an all-around bad guy. There's no possibility that he has the hero's goodwill at heart. Doctor Doom's origin made him a villain, and it's easy to see why. His mother died as a result of a botched deal with Mephisto, always came in as a close second to Reed Richards, and got visibly scarred by a machine intended to contact his dead mother. We've seen villains motivated by less, so Doom's direction in life makes sense.
Secondly, the character isn't a resurrected Tony Stark. General audiences might be confused by an actor playing multiple roles in the same movie universe, and these are two distinct individuals. It's not a doppelganger situation or a sci-fi resurrection—the way Phil Coulson (Clark Gregg) returned in Marvel's Agents of SHIELD. Doctor Doom is a completely different person.
Mind you, Feige and the writers over at Marvel may take creative liberties with the character. Practically every MCU project, while true to the source material, has taken some liberties with the narrative. The Infinity Saga is a perfect example since most pivotal scenes came directly from the comics. It differed slightly but close enough that the comics lay out a blueprint for future movies.
Another key point about Doom coming to the MCU is it may happen earlier than anticipated. RDJ's only confirmed roles are in Avengers: Doomsday and Secret Wars, although this year's Fantastic Four: First Steps movie could include a surprise appearance. Doctor Doom is notoriously known as a villain of the Fantastic Four, which means a cameo is plausible. And Marvel's predisposition to tease major characters with post-credits sequences points to a scene reintroducing Victor Von Doom. Galactus and the Silver Surfer are the antagonists in First Steps, but that doesn't rule out a cameo.
One concern that's a complete unknown is where Victor Von Doom has been this entire time. So many cataclysmic events have happened in the MCU, yet Doom has kept to himself. Perhaps it's due to never hearing about Latveria despite its existence. An embassy flag in 2008's The Incredible Hulk confirmed that the country exists in some form.
Whatever the reason, Doom's first appearance will probably allude to his past. Maybe he's in prison, still on his quest for revenge against Mephisto, or perhaps Victor is from another universe. The last explanation is the most plausible since two characters sharing identical faces would be too much of a coincidence. He must be a variant. Said trait doesn't take anything away from the character; it just provides a logical explanation for how Marvel is introducing a new character with the same face as another.
Audiences understand how an actor can be dual-cast in separate projects, but the people within the MCU—on the Sacred Timeline—will ask questions when Doom shows up with Tony Stark's face. Having him be a variant sorts out the finite issues while simultaneously creating talking points. Consider Peter Parker's reaction when he sees Doctor Doom up on an LED board, announcing his desire to rule the world. And Parker is one of many characters who will react to him and Tony Stark sharing a face.
Avengers: Doomsday premieres on May 1, 2026. Avengers: Secret Wars premiers on May 7, 2027. And the Untitled Spider-Man 4 premieres on July 24, 2026.