New footage shown at San Diego Comic-Con's Marvel Hall H panel has fuelled speculation that Doctor Doom's motivations in Avengers: Doomsday will mirror Tony Stark's greatest fear from Avengers: Endgame. Both characters are played by Robert Downey Jr., and the leaked clips suggest Doom's villainous plan stems from personal loss caused, directly or indirectly, by the Avengers' actions, echoing Stark's own fear of losing his daughter Morgan.

In the footage, Sue Storm describes Victor Von Doom as once kind and caring before "everything he loved was taken from him", while Doom himself accuses the heroes of having "stolen lives" that must now be returned. The prevailing theory links this to Steve Rogers' time-travel choices at the end of Endgame, which may have inadvertently caused a multiversal catastrophe that killed Doom's wife and/or daughter. This would parallel a deleted Endgame scene in which Stark confesses to a teenage Morgan that he feared the Avengers' time heist could have erased her from existence, suggesting Doom could be viewed as a dark mirror of Stark. Avengers: Doomsday is set for release on 18 December 2026.