March 20, 2019... a day that will live in infamy for Marvel fans. This date saw the official end of the Disney/Fox merger, thus ushering in a pantheon of Marvel's most beloved characters and villains such as the X-Men, Fantastic-Four and Dr. Doom to name but a few. The burning question since that time for both Kevin Feige and Disney is how mutants will be introduced to the Marvel Cinematic Universe. This is no small order, and each possibility has its own implications and difficulties to immersing a literal encyclopedia of characters into an MCU that has spanned over a decade and has already established a multitude of beloved characters such as the Avengers. Below are the most plausible scenarios that we can expect to see from Marvel and Kevin Feige so let us get into it.
The Scarlet Witch creates mutants in the MCU
It has been widely discussed that Marvel's current Wandavision series is being loosely adapted from the 'House of M' storyline, an 8-issue run in 2005 wherein Wanda Maximoff ends most mutants by simply uttering the words, "no more mutants." In the aftermath of this storyline, Cerebro estimated that 91.4% of all mutants were eliminated at that time, that's a number in the millions.
However, since no mutants technically exist in the current 616 timeline, Wanda cannot simply eliminate mutants. But, since the "House of M" adaptation is only partial, Marvel could use Wanda's reality-warping ability to do the opposite which is to create mutants. We have already seen hints that whatever Wanda creates within her sitcom world, also continues to exist outside of the 'Westview anomaly' so this is not outside the scope of her powers or possibility.
This would be a quick and easy way for Marvel to create mutants and bring them into the MCU.
Mutants already exist in the MCU
Within the universe he was creating, Kevin Feige gave us a hint that mutants existed as far back as the 2008 Iron Man movie. Check out this deleted post-credit scene from the original Iron Man.
This clip shows us that mutants existed within the Marvel continuity at that time, although in "assorted" numbers which is to say, not many. It is also clear that the only barrier to this reveal was a business one in that legal issues prevented Disney from using mutants because Fox had ownership rights over that word and the characters themselves. Despite this, it appeared as though Kevin Feige was interested in promoting the idea that the x-gene existed and had begun to reach a non-dormant state within the population.
Additionally, excerpts from the Wakanda Files give us another peek into the possibility that the dormant x-gene currently exists and that both Wanda and Pietro Maximoff are mutants themselves. This in-universe book was written by Shuri of Wakanda while researching Hydra and in it she notes that Hydra found 'genetic oddities' among the inhabitants of Sokovia which made them ideal candidates for their Mind Stone experiments. In these notes, it was further explained that their exposure to the energy of the Mind Stone unlocked their latent powers. Further, there is a separate passage that mentions that the twins', 'abhorrence for Tony Stark' also played a figural role in the development of their powers that the other Sokovians did not exhibit.
This is interesting because we know from comic book lore that anger, rage, or some form of emotional trauma often unlocked and triggered the mutant genes within individuals.
Mutants will be introduced to the MCU via the Multiverse storylines
If these options are plausible and mutants already existed, one question that fans have been asking for years is, where have they been? Why didn't they help in the battle of New York or during Endgame? There may indeed be some logical explanations for this but let us just take these as they are and admit that these are questions that Marvel is now needing to answer.
Enter the multiverse. As Wandavision kicks off phase 4, it became quite clear that Marvel is heading in some bold new directions. Events will transpire in this series that will have significant implications into several properties and will impact Spider-Man 3, Doctor Strange in the Multiverse of Madness and even the Loki Disney+ series and all have multiverse implications.
The idea of bringing mutants through a rupture in the multiverse would be quite simple and could also explain the glaring absence of mutants as well as give us another clean beginning to mutant kind. Afterall, it is clear from production information on the set of the Spider-man threequel that multiple villains will be joining the 616 timeline from alternate timelines, if even for a short time.
Having various X-men characters, assorted mutants or other super-powered beings spill over into our continuity (or be available in other continuities) would solve a lot of problems and would also provide some intriguing possibilities for future projects.
Thanos' Snap introduced mutants to the MCU
At the beginning of Avengers: Endgame, when speaking to the group, Rocket said, "when Thanos snapped his fingers, earth became ground-zero for a power surge of ridiculously cosmic proportions..."
If we build on the prior theory that the mutant x-gene already exists in its dormant state, then the power unleashed by Thanos, multiplied significantly from what Wanda and Pietro experienced via the Mind Stone, would likely trigger a similar, even larger, effect on anyone exhibiting the same genetic disposition.
To reiterate, Wanda and Pietro shared a genetic anomaly that likely exists in others although perhaps not to the measurable density as seen in Sokovia. Nonetheless, their powers were unlocked by exposure to the Mind Stone. Thanos' snap was performed on earth but with the power of all six of the Infinity Stones. And let us not forget, the earth has been 'ground zero' for no less than three snaps.
The idea that the energy released from the power of the Infinity Stones fueled the evolution of the x-gene is not far-fetched.
A hybrid theory brings mutants to the MCU
Now, let's use a bit of logic and quickly parse out these theories to determine which is the most probable theory of how Marvel will bring mutants into the MCU. As with many things in life, the truth is usually somewhere in the middle of conflicting theories and I think this holds true here.
Basically, mutants already exist in the MCU although they are likely not yet so prolific. What Nick Fury said at the end of Iron Man is true. The dormant x-gene has likely begun to emerge in random individuals over many years as they become exposed to a variety of stimuli. More so, Thanos' snap likely exacerbated the mutation and evolution of the x-gene, like how Wanda and Pietro's powers were also triggered by the Mind Stone due to their own exposure to the cosmic energy the stones give off.
The multiverse or "House of M" theories do not work for a simple reason. They are far too simplistic. Kevin Feige has never shown any inclination that he would treat something so complex and important to the future of the MCU with anything so basic an idea and so full of plot holes and absurdities. This 'way out' would bely all the hints and easter eggs we have had so far through over a decade of storytelling. To put another way, it would cheapen the Marvel brand in my opinion. Everything we have seen up to now has shown us that Marvel does not take the quick and easy way out.
No doubt, Marvel has an answer to this problem and have already begun to implement it so one thing is for sure, we will see mutants in the MCU very soon!