Doctor Doom is expected to wear his familiar metal mask for much of the film, but the moment his face is shown, the resemblance to Stark would likely become an issue inside the story.
That would matter to characters who knew Tony closely, including Thor, Steve Rogers, and Doctor Strange.
Adding a clue inside Avengers: Endgame could make that resemblance feel less abrupt when Avengers: Doomsday arrives. It could also give the Russos and writers Michael Waldron and Stephen McFeely a firmer bridge between the Infinity Saga and the Multiverse Saga.
That bridge may be important because the Multiverse Saga has had a less direct path than the Infinity Saga. The next Avengers film now has to gather several major storylines and make them feel like one payoff.
Planting new material inside Endgame lets Marvel point back to one of its strongest films while reframing the road to Doomsday.
Marvel Can Use Its Returning Stars More Directly
Downey has already been involved with Avengers: Doomsday, which would make additional Stark material for the Endgame re-release easier to justify from a production standpoint.
The same logic applies to Evans, whose Steve Rogers may also receive new context after his final Infinity Stones mission.
Marvel has not confirmed that either actor appears in the added Endgame scenes. Still, with both names already back in the MCU conversation, the studio now has a practical way to use them without treating Avengers: Endgame as unfinished business.
Avengers: Doomsday is scheduled to hit theaters on December 18, 2026.
