Is Robert Downey Jr. really Doctor Doom? Benedict Cumberbatch's confusing Doomsday comments fuel new theory

Robert Downey Jr. is coming back to the MCU. That part isn't in dispute. What fans can't agree on anymore is who is actually behind the mask.

The theory took off after eagle-eyed viewers picked apart the latest trailer footage and noticed the eyes glimpsed through Doom's mask read as blue-green rather than Downey's brown, and that his face is never fully shown. Combine that with the four minutes Marvel is adding back into the Endgame re-release next month, reportedly to seed Doomsday more directly, and a theory has caught fire: Downey's Doom might be a decoy, set up to die early, with the "real" Doom revealed later and Benedict Cumberbatch's Doctor Strange playing a far bigger role than anyone's been told.

Cumberbatch himself has spent over a year contradicting his own timeline on this. He initially let slip to Variety that Strange wouldn't appear in Doomsday at all, blurting out "Is that a spoiler?" He explained the character's absence came down to Strange not fitting this chapter of the story, following Marvel's decision to scrap Jonathan Majors' Kang as the saga's central villain, and instead teased a much bigger part for Strange in Avengers: Secret Wars, calling him "quite central to where things might go."

Then he reversed himself. Asked point-blank whether Marvel had corrected him, Cumberbatch admitted "I got that wrong, I am in the next one," before adding, only half-joking, not to believe anything he says. When Marvel finally dropped the full Doomsday cast list this spring, Cumberbatch's name was conspicuously missing, and he later joked to a Brazilian outlet that maybe there just weren't enough chairs.

That flip-flopping is exactly what's feeding the fan theory's more elaborate cousin: that Strange isn't a red herring for who Doom is, but a red herring for what role he'll play. One version, pulled from Marvel's Secret Wars comics, imagines Doom eventually restructuring the multiverse into a patchwork world called Battleworld, and installing Strange as its "Sheriff," a morally compromised enforcer rather than a hero fighting him. It would explain both the marketing silence around Cumberbatch and his repeated hints that Strange's real arc is being saved for Secret Wars in 2027.

Officially, Marvel still hasn't confirmed Cumberbatch's Doomsday involvement at all. Unofficially, reporting suggests his return is very much on the table, just not necessarily as the hero fans remember.

Avengers: Doomsday hits theaters December 18, 2026.