<p>The Fantastic Four would come up as scientists that travel to another dimension, maybe through Hank Pym's experimental Pym Particles, and get mutated with weird elements. The result would make all of them develop powers,</p><p>
</p><p>Also, one thing. Did anyone realized that each Fantastic Four members has powers that match those of the four elements? The Thing is Earth, Human Torch is Fire, Sue Storm is Air (she is invisible like air), and Mr.Fantastic is Water (flexibe and elastic like water). I realized this a little time ago by myself, not a big deal, but a funny thought.</p>

<p>Honestly, I don’t like the idea of the F4 or even the X-Men for that matter coming from alternate dimensions. They should originate from the Prime MCU Reality Earth-19999 (or 616 according to FFH).</p><p>
</p><p>Well of course, the heroes can originate from being exposed to extradimensional energy or something like that, but Reed Richards needs to be a human from Prime MCU Reality, not someone who came to the MCU through a hole in spacetime.</p><p>
</p>

<p>@SonOfAres1 On Earth-311 the Fantastic Four got their powers by being exposed to some strange green light in the Sargasso Sea. I wouldn't mind seeing something like that in the MCU, maybe with the Bermuda Triangle instead of the Sargasso Sea.</p>

<p>They don't need to do anything special to introduce the Fantastic Four. Same as always, space travel, cosmic rays, that'll do it. It's the X-Men that'll be the hard one, because mutants aren't a thing in the MCU (If they were, it would've been mentioned at some point in Agents of SHIELD at least.), so they'll have to come up with some new explanation as to how they got their powers.</p>

<p>@BlackWidower My ideal method of introducing mutants would be through the radiation emitted by the Infinity Stones. When Thanos snapped his fingers, he unleashed a massive wave of cosmic radiation across the Earth, and then Hulk snapped, and then Iron Man snapped...</p><p>
</p><p>This radiation would have been powerful, but thinly distributed across the Earth. And the massive worldwide wave of mutants could originate from random people developing the X-Gene.</p><p>
</p><p>To explain mutants who came before this massive wave of radiation, you could look to other sources of cosmic radiation or to contact with the Infinity Stones.</p><p>
</p><p>For instance, my ideal method of introducing Magneto to the MCU would be this: Max Eisenhardt was an 11 year old boy in Sokovia when HYDRA took over. He and his family were placed in concentration camps / mass prisons designed to control the population. The Mind Stone on site emitted radiation and, combined with the trauma experienced, gave him his mutation.</p><p>
</p><p>Just a concept.</p>

<p>The FF’s first movie takes place in the 60s, and them getting powers. (unknowingly at this point, it was as a result of silver surfer) The movie ends with them going into the negative zone, and them come out nearly 70 years later in the 2020s, post endgame. That way the FF retain their aesthetic and “style”. Like Cap, they have to find themselves in this new world, although each one will find it differently. (Ex. Reed can be fascinated so much by the new technology and science, he becomes more and more reserved in his work and becomes oblivious to what’s around him)</p><p>
</p><p>The MCU can introduce mutants like this: </p><p>
</p><p>(When mutants inevitably show themselves, they’re going to be discriminated not because they have powers, but because they can’t control them/a lot of powers are uncontrollable.)</p><p>
</p><p>Prof. X erased the minds mutants from humans after a large mutant accident 20-30 years ago. The accident wasn’t caused by the X Men, but it looks like it. Any and all mutants that Xavier can convince retreat to a island called Utopia. He occasionally sends out search parties to bring in new mutants and help/save them. Xavier knows what’s going on in the outside world, but many on the island don’t. After the Avengers undo the snap, Xavier now knows it’s time to return to the world, and also bring back the X Men. </p>