Although we've been promised numerous times that the upcoming Dark Phoenix is adapting The Dark Phoenix Saga more faithfully than X-Men: The Last Stand did in 2006, as with most comic book movies, this new version is taking various creative liberties. This becomes especially evident after watching the first Dark Phoenix trailer, during which time we see Jessica Chastain's unnamed, villainous alien character. Working off the little information that has been revealed about who Chastain is playing, some fans have speculated that the actress is playing an altered version of Mastermind, who manipulated Jean Grey in The Dark Phoenix Saga. Director Simon Kinberg has debunked this idea, but he did note that Chastain's character does share some similarities to Mastermind, saying:
I will say that Jessica's character is not Mastermind but there are elements of the way Mastermind manipulates Jean that Jessica's character does employ. For me, as you'll see, that Jessica's character has elements of a few different characters from the comics.
So while we won't see Jessica Chastain as a female version of Mastermind casting illusions, some of the tactics she employs in Dark Phoenix will be reminiscent of what Mastermind used in the comics. For those unfamiliar with Mastermind, real name Jason Wyngarde, he started out in the comics as a member of Magneto's Brotherhood of Evil Mutants, but later on he became a member of the Hellfire Club. During this time in the organization in The Dark Phoenix Saga, he used his illusions and a mind-tap device created by Emma Frost to convince Jean Grey that she was living a life as a Victorian aristocrat who was married to Mastermind and serving on the Hellfire Club as the Black Queen, thus turning her against the other X-Men. Unfortunately for Mastermind and the rest of the Club, Jean, who by now had turned into Phoenix, eventually broke free from Mastermind's control and made him experience godhood for a brief moment in his mind, which left him catatonic.
We won't see any of this in Dark Phoenix, although since Jessica Chastain's character has been described as an "otherworldly shapeshifter," she presumably will be altering her form in front of Jean Grey. Although unwilling to get too specific, Sophie Turner also elaborated a little to IGN bit on Jean Grey's relationship with Chastain's character. As the actress stated:
It's an interesting one and I don't want to spill too much about it but basically Jessica's character is very interested in this power that I've kind of acquired and this cosmic force that I have and she kind of wants that force to use it for her own -- she has her own intentions with it and she kind of wants to use that. And she nurtures me in a way to make me kind of trust her.
Whatever Jessica Chastain's character has in store for Jean Grey, it will be up to the X-Men, Magneto and all the other mutant players involved to stop Jean/Phoenix from causing widespread destruction and from being used by these mysterious aliens who want to rule the galaxy.
Dark Phoenix opens in theaters on February 14, 2019. Don't forget to also look through our X-Men movies guide to learn what other mutant-centric projects are in development.