Theories abound as to the potential effects of all the reality-shifting activities that occurred throughout Avengers: Infinity War and Endgame.
Ever since Disney acquired the movie assets of 21st Century Fox, speculation has surrounded the studio’s plans for the X-Men and Fantastic Four, the Marvel superhero teams that were previously under the Fox banner.
A fan theory suggests that Marvel might have found a convenient way to introduce one of the Fantastic Four’s greatest foes via Endgame — and by association, primed audiences for the Fantastic Four to enter the MCU, too.
As Reddit user UpwardSpiral00 explains it, Thanos was too smart not to have a “backup plan” for reducing the population of the universe — after all, even after he snapped the population in half, it would eventually return to the prior levels.
Steve Rogers’ decision to travel back in time during Endgame and live out the rest of his life in the past with Peggy Carter opened up all kinds of speculative doors when it comes to Captain America and the MCU timeline.
One popular theory was seemingly confirmed by the film’s writing team, with Endgame co-writer Christopher Markus indicating that yes, Steve’s decision did indeed result in two versions of Captain America existing simultaneously in the MCU: The Captain America from Endgame that traveled back, and the Captain America from all of the prior films.