Fox and Disney are nearing a deal that could bring the X-Men and Fantastic Four franchises into the Marvel Cinematic Universe, and as a result, fans are freaking out about the possibilities that come with a truly complete Marvel Comics universe on the big screen.
However, before we get to that promised land of seeing Wolverine, Hulk, and Spider-Man all trading quips, blows, and handshakes, there's still the major looming question of how the X-Men and Fantastic Four's entrance into the MCU gets explained. Up until now, the MCU has only known the Inhumans as a race of superpowered genetic anomalies that are to be hated and feared, so how could the concept of mutants have gone so unnoticed? And what would it mean that they suddenly come into the picture?
The same question applies to a team that's as well-known and public as the Fantastic Four. Thanks to Marvel Comics lore, there may already be a clear and easy answer.
We just got done breaking down the theory that the next X-Men movie, Dark Phoenix, could feature a battle between Jean Grey's Dark Phoenix and the Professor X/Magneto hybrid entity, Onslaught. As stated in that article, this is a development that could be a perfect entryway for Fox's Marvel properties to join the MCU. Both Dark Phoenix and Onslaught are characters who have been responsible, respectively, for changing the entire nature of reality in the Marvel Universe. In fact, the Onslaught crossover event in Marvel Comics served as a lead intoa major shift in the company in the form of "Heroes Reborn" launching.
"Heroes Reborn" occurred after the Avengers and Fantastic Four apparently died while battling Onslaught. Instead of dying, these characters were transported into a pocket universe created by Fantastic Four couple Reed Richards and Sue Storm's son, Franklin. In this pocket reality, the Avengers and Fantastic Four lived very different lives, as imagined by creators like Jim Lee and Rob Liefeld, until they were re-incorporated into the main Marvel Universe.
In order to bring the X-Men into the MCU, "Heroes Reborn" could be flipped around the other way: If a battle between Phoenix and Onslaught tears apart the reality of the X-Men movies, Fox's entire Marvel franchise could be revealed to be a pocket reality with the Phoenix/Onslaught battle ripping open that pocket dimension, allowing the X-Men and Fantastic Four to be "reborn" into the actual reality of the MCU. The delay in acknowledging mutants in the MCU could be explained by the same Marvel multiverse theory Agents of SHIELD just introduced, while the messy turns of the X-Men and Fantastic Four movie franchises since the 2000s could be viewed as something akin to a bad dream, before Marvel Studios establishes the "real" versions of these characters. With Avengers: Infinity War introducing the reality altering power of the Infinity Gauntlet, the Avengers-verse is also primed to explain outlandish developments like a whole pocket dimension existing within the main MCU.
Avengers: Infinity War opens in theaters on May 4, 2018. Thor: Ragnarok is now playing in theaters. Other upcoming Marvel Cinematic Universe movies include Black Panther on February 16, 2018, Ant-Man and the Wasp on July 6, 2018, Captain Marvel on March 8, 2019, the fourth Avengers movie on May 3, 2019, the sequel to Spider-Man: Homecoming on July 5, 2019, and Guardians of the Galaxy Vol. 3 in 2020.
The X-Men film universe continues with The New Mutants on April 13th; Untitled Deadpool Sequel on June 1st; and X-Men: Dark Phoenix on November 2nd.