Robert Downey Jr.’s Doctor Doom role could temporarily bring back his original Iron Man variant in Avengers: Doomsday. Throughout eleven MCU movies, Robert Downey Jr. built a comprehensive Iron Man arc that brought Tony Stark from a selfish warmonger to a universe-saving hero respected by the TVA itself. Avengers: Endgame gave Iron Man a well-deserved and definitive farewell, but Robert Downey Jr. will return six years afterward as Doctor Doom, Avengers: Doomsday‘s main villain. Doctor Doom’s origin, backstory, and the reason why he’s played by the same actor are unknown.

As Avengers: Doomsday‘s cast announcement suggests, Avengers: Doomsday will introduce a new set of X-Men variants played by Fox’s original X-Men cast. Due to the Phase 6 movie’s multiversal nature, it’s technically possible for any Marvel character to return. However, characters such as Robert Downey Jr.’s Iron Man and Chris Evans’ Captain America are unlikely to return, as it would undo their Avengers: Endgame ending. Instead, a couple dozen other heroes will team up to fight Doctor Doom.

Avengers: Doomsday Makes It Possible For Robert Downey Jr. To Return As Iron Man Through Flashbacks

Marvel Studios Might Make The Most Out Of Robert Downey Jr.’s MCU Return

Iron Man’s ultimate sacrifice in Avengers: Endgame marked the definitive ending of his MCU arc and the final appearance of Robert Downey Jr. in his career-defining Marvel role. While the MCU has had plenty of opportunities to bring back Downey as Iron Man, either through the multiverse or through flashbacks, any cameo or guest appearance risks diminishing the dramatic impact of Tony Stark’s death. Loki, What If…?, Doctor Strange in the Multiverse of Madness, and ᴅᴇᴀᴅpool & Wolverine skipped Iron Man cameos for this reason.

Watching new Iron Man footage on the big screen may sound like an impossible scenario at this point, but Robert Downey Jr.’s return opens up the opportunity to film more scenes with Downey in his original MCU role. While most of Downey’s Avengers: Doomsday screentime will go to his Doctor Doom scenes, Avengers: Doomsday could also feature brand-new Iron Man scenes from before Tony Stark’s Avengers: Endgame death. Iron Man flashbacks could cover moments that tie into Avengers: Doomsday‘s plot in some way or flashbacks that show important interactions between Tony Stark and other characters.

What Iron Man Moments The MCU Can Revisit In Avengers: Doomsday

The Infinity Saga Skipped Long Periods Of Tony Stark’s Life

Iron Man may have been the Infinity Saga’s protagonist, but the MCU didn’t cover the entirety of his Iron Man journey, let alone his pre-Iron Man days. Tony Stark’s hard days coping with The Avengers‘ Battle of New York were acknowledged but not shown by Iron Man 3, Avengers: Age of Ultron glossed over the Avengers’ few battles together, and Avengers: Infinity War didn’t address how Iron Man dealt with the Avengers’ disbandment. The five years between Avengers: Infinity War and Avengers: Endgame also remain completely unexplored to this day.

Robert Downey Jr.’s hypothetical return as Iron Man in Avengers: Doomsday flashbacks could tie directly into Avengers: Doosmday‘s main conflict. WandaVision showed how a Stark Industries missile killed Wanda and Pietro Maximoff’s parents through flashbacks, and Captain America: Civil War established that Baron Zemo wanted to avenge Sokovia’s destruction after Iron Man and the Avengers’ catastrophic battle with Ultron in Avengers: Age of Ultron. Likewise, Avengers: Doomsday could reveal that Tony Stark was onto something related to Doctor Doom at some point before Avengers: Endgame.

Iron Man’s Brief Return In Doomsday Could Explain Why Doctor Doom Looks Like Tony Stark

Iron Man Might Still Be Relevant To The MCU In Phase 6

Naturally, the reason why Robert Downey Jr. was cast as Doctor Doom only a few years after retiring his Iron Man portrayal is a big question surrounding Avengers: Doomsday and Avengers: Secret Wars, leading to creative speculation about possible in-universe explanations. If Avengers: Doomsday and Avengers: Secret Wars show Doctor Doom’s unmasked face, the villain’s familiar appearance could be explained with the help of Tony Stark flashbacks. Avengers: Doomsday could reveal that Tony Stark’s discovery of time travel linked him to an alternate-universe Doctor Doom in some way, or that Stark had a connection to Earth-616’s Latveria and its ruler prior to his death.

The explanation for Doctor Doom’s resemblance to Tony Stark might require new Iron Man footage. If Robert Downey Jr.’s original Iron Man wasn’t aware of Doctor Doom before his death, then Doctor Doom could have a connection to an alternate-universe variant of Tony Stark. In that case, Avengers: Doomsday could introduce a new Iron Man variant played by Robert Downey Jr. — one who becomes Doctor Doom or whose appearance gets stolen by Doom.

Upcoming MCU Movies

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  Thunderbolts*

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  May 2, 2025
  

  
  
  
  

  
  

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  The Fantastic Four: First Steps

  Release Date

  
  July 25, 2025
  

  
  
  
  

  
  

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  Avengers: Doomsday (2026)

  
  
  
  
  

  
  

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  Spider-Man: Brand New Day

  Release Date

  
  July 31, 2026
  

  
  
  
  

  
  

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  Avengers: Secret Wars

  Release Date

  
  May 7, 2027
  

  
  
  
  

  
  

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