Marvel Studios President Kevin Feige chimed in on what's arguably the biggest surprise of WandaVision and possibly the Marvel Cinematic Universe in the return and reveal of a character long thought to be dead. During Disney's presentation for the Television Critics Association, he talked about the surprise casting of Evan Peters, who played the FOX incarnation of Quicksilver for their X-Men Cinematic Universe despite the MCU's own version of the character that already existed as played by Aaron Taylor-Johnson. As Wanda's (Elizabeth Olsen) twin brother, Pietro died during the events of 2015's Avengers: The Age of Ultron. With Peters' appearance on the Disney+ series, Darcy Lewis (Kat Dennings) describe the surprise as a "recasting" when he showed up at Wanda's door.
Feige said it was "relatively early on in the development process" when it was decided that Peters will join the series and that "there are discussions on everything, at one point or another" when it came to debating which version of Quicksilver would show up. In episode 7 "Breaking the Fourth Wall". Agatha (Kathryn Hahn) was revealed to be the mastermind of manipulating Wanda to create the world within Westview, New Jersey, and manipulating the townsfolk to be the revolving sitcom characters. It still doesn't explain what Fox Pietro's role and origins will be as we come to the final two episodes of the season as Marvel continues to tease the multiverse.
Now that the Fox can of worms has been opened, will we see anymore X-Men cast members into the fold in the remaining episodes? Obviously, with Spider-Man: Far From Home (2019) first breaching the subject, continuing it in the sequel No Way Home, and Olsen's upcoming appearance in Doctor Strange and the Multiverse of Madness, we'll start to see more of the expanded sandbox come into play. New episodes of WandaVision stream Fridays on Disney+.