The Marvel Cinematic Universe has used the multiverse as a storytelling device since before the Multiverse Saga even began, highlighted by Captain America and the events of Avengers: Endgame. With the upcoming release of The Fantastic Four impending, narrative questions have reasonably arisen about the impacts of multiversal time travel. While time travel in the MCU has not immediately created various branching timelines like in DC’s The Flash, Captain America’s return to the main MCU timeline has raised questions of continuity that continue unanswered to this day.

In the Marvel Cinematic Universe, the butterfly effect does not appear to exist in every scenario. Still, Marvel has worked hard to retain stakes within a changing, branching universe, telling character-centric stories that hop between dimensions in Doctor Strange: In The Multiverse Of Madness and Spider-Man: No Way Home. Fortunately, the MCU has a good handle on picking and choosing the elements of multiverse and time travel that best impact the stories that they wish to tell. However, this inevitably raises concerns about narrative consistency, and everything we know about The Fantastic Four and its 1960s setting complicates things.