Possibly the biggest question amongst fans about the upcoming phase of the MCU is how the filmmakers plan to introduce the First Family of Marvel, the Fantastic Four, into the franchise. While traditionally the Four’s origin tale is unrelated to other heroes, given how interconnected the lives of the characters are shown to be in the movies, it could very well be a familiar face who has a hand in their arrival. In fact, one new theory even goes so far as to say that Scott Lang may be responsible for their debut.
The Quantum Realm introduced in Ant-Man and the Wasp is a largely unexplored micro-verse, and a convenient plot device that can be used to hand-wave away the most outrageous parts of the films, from magic to time travel to mutants. It wouldn’t be too much of a stretch then to have the Realm take the place of the cosmic event that granted the Fantastic Four their powers in the comics.
Here’s how the Redditor puts it:
The “Quantum city” we saw in Ant man & the wasp play key role in introduction of F4 and Kang.the city I believe is Chronopolis -city of Kang the conqueror. My theory is that Fantastic four were stuck in Quantum realm during 1960s, when they visited the realm for the fist time – they got superpowers in N zone (a more dangerous part of quantum realm ) and then they had to face Rulers of Negative zone (either Annihilus or Blastaar) but they got stuck there in the process.
I believe it wasn’t a accident but a planned act of Kang who wants Reed Richards for his own selfish reason since Reeds is great great grandfather of Nathaniel Richards aka Kang. I think at the end of Ant man 3 , Scott or Janet (who knows quantum city) visits the Chronopolis and free the members of Fantastic Four and bring them to real world.
With mentions of a mysterious city within the Quantum Realm already found in the MCU, it’s almost a guarantee that inhabitants of the city will have an impact on the future of the cinematic universe, whether they turn out to be the Fantastic Four or something more sinister, like Kang, the lord of time.
If this proposed fan theory does turn out to be true tough, it’d mean that the Fantastic Four origin movie would be similar to Captain Marvel’s, where the heroes start out living in the past before getting trapped in the Quantum Realm and then emerging into the present day to join forces with the current Avengers. And once the Fantastic Four enter the mix, you know it’s only a matter of time until they’re challenged by some of the most iconic villains in Marvel history, like Galactus, the Eater of Worlds and Doctor Victor Von Doom.