Since she was announced to be a cast member of the upcoming X-Men: Dark Phoenix, fans have been speculating on the identity of Jessica Chaistain's mystery character. Her influence and role in the newest adaptation of Uncanny X-Men's classic "Dark Phoenix Saga" storyline seems to be riffing off the role formerly held by Mastermind in the original story, but she doesn't seem to be playing that character.
Although fans have considered the possibility of her character being a Skrull, Cassandra Nova or even Lilandra of the Shi'Ar, aone theory suggests they may not have been going big enough -- what if Chastain is an avatar of the Phoenix Force itself as it communicates with Jean? The newest trailer provides the most compelling argument to date for this possibility.
The Usual Suspects
Early speculation hinted that Chastain would be playing a version of the Shi'Ar Empress, Lilandra. Despite the character, or even the concept of aliens, never being formally introduced into the X-Men film universe, it seemed bolstered by the original synopsis of the film. The synopsis included the line "Now, with this family falling apart, they must find a way to unite -- not only to save Jean's soul, but to save our very planet from aliens who wish to weaponize this force and rule the galaxy."
This helped foster much of the speculation that Chastain would be playing Lilandra, and for good reason. Lilandra had a major role in the both the original "Phoenix Saga" and "The Dark Phoenix" in the comics, so the film introducing her would make sense as it introduces the cosmic concept of the Phoenix. However, that line was later dropped from the film's synopsis, replaced with a very different statement. "The film is the most intense and emotional X-Men movie ever made," the new version reads. "It is the culmination of 20 years of X-Men movies, as the family of mutants that we've come to know and love must face their most devastating enemy yet -- one of their own."
This text shifts the focus away from alien forces that could be trying to manipulate the Phoenix Force and more towards the "devastating" effect the Force has on the X-Men. Lilandra likely wouldn't have that kind of full effect on Jean, especially if she's never appeared before, but someone else could corrupt her and turning her dark with near ease.
In the original comic, this role was given to Jason Wyngarde, otherwise known as Mastermind. Formerly of the Brotherhood of Evil Mutants, Mastermind joined the Hellfire Club and began trying to manipulate Jean with his illusion powers shortly after she gained the powers of the Phoenix. He eventually succeeded in twisting the hero into briefly joining the Hellfire Club as its Black Queen, but when she broke free of his conditioning, she turned on him and opened up his mind to the totality of the cosmos, driving him mad.
Some fans have noted how Chastain's character communicates with Jean, often conjuring brilliant stars out of seemingly nothing. It provides a nice visual backdrop for the characters to talk against, but it may also suggest what kind of powers the character has. It's clearly an illusion of some kind, indicating the possibility that Chaistain may be playing Mastermind -- but we don't think this is the case. In the X-Men films, the Hellfire Club was practically wiped out by the end of X-Men: First Class. And though a character named Jason with similar illusion abilities was introduced in X2: X-Men United, that character was revealed to be the son of William Stryker.
Even more directly, the film's writer and director, Simon Kinberg, actually shot down this theory in an interview last year, but suggested that some of his manipulative tactics have been given to Chastain's unnamed character.
It's more likely that those display of powers are part of a psychic conversation between Jean and the Phoenix Force itself, represented on screen by Chastain. It would explain why these moments are often so cosmic in nature, taking the pair through the stars themselves; a fitting setting for an otherworldly and eternal force that comes from space. It would also explain why, in the most recent trailer for the film, no one other than Jean seems to acknowledge Chastain's character's presence, even though she's obviously someone who knows more about the Phoenix Force than anyone, given her knowing comment about the Phoenix power destroying everything it touches except Jean.
If none of the other X-Men knew of her influence on Jean, then they would ascribe all of the Dark Phoenix's crimes to Jean alone. There's no Jessica Chaistain for the team to stop; they just know they have to contend with their friend, her ever-expanding powers and degrading mental stability. Earlier trailers have even included lines like "the mind is a fragile thing. It only takes the slightest tap to tip it in the wrong direction" and Jean tearfully asking someone "why did you make me do that?" This suggests Jean is being somewhat controlled and pushed, and giving in to the Phoenix Force would be a good explanation of that.
The Phoenix Force is typically depicted as a corrupting influence. Having its influence on Jean be the primary antagonist of the film is a compelling idea, and one we think the trailers have been hinting at all along. But we'll find out for sure when the film comes out later this year.
Written and directed by Simon Kinberg, Dark Phoenix stars James McAvoy, Michael Fassbender, Jennifer Lawrence, Nicholas Hoult, Sophie Turner, Tye Sheridan, Alexandra Shipp, Kodi Smit-McPhee, Evan Peters and Jessica Chastain. The film is scheduled to be released on June 7.