The X-men comics have always been one big mutant soap opera, and that's been reflected in the movies as well. The first trilogy centered on the love triangle between Cyclops, Jean Grey, and Wolverine, and the romantic entanglements haven't gone away as the focus shifted to the young core of students. X-men: First Class and X-men: Days of Future Past had the relationship between Xavier (James McAvoy), Mystique (Jennifer Lawrence), and Magneto (Michael Fassbender) at their core, and now we're seeing it from another angle in 2016's X-men: Apocalypse.
In an extensive piece of Lawrence's career, THR notes that X-men: Apocalypse will highlight the romance between Mystique and Magneto. Sorry, all of you hoping Mystique and Hank "Beast" McCoy (Nicholas Hoult) would finally hook up, butt hat doesn't seem to be happening. Then again, screenwriter Simon Kinberg has previously stated how he finds the Mystique/Beast friendship potentially interesting, with a hope of exploring it more in 'Apocalypse'.
The point of this seems to be that Mystique is going to get her moment to shine. The first film was largely about Magneto, the second was about Xavier, so it make sense she would be at the center of the next. Plus, Lawrence and Fassbender are much bigger stars now than they were a few years ago.
Bryan Singer will return to direct X-men: Apocalypse for May 27th 2016.
