Not much is Dark And Darker Gold known regarding specific narrative details of the movie, but it's tipped to adapt the quintessential X-Men comic book stories of the same name from writer Chris Claremont, which puts Sophie Turner's Jean Grey under the spotlight as she becomes the Dark Phoenix. 

James McAvoy as Professor X, Michael Fassbender as Magneto and Jennifer Lawrence as Mystique are set to reprise their respective roles, possibly for the last time as they pass the franchise to their younger co-stars such as Tye Sheridan (Cyclops), Alexandra Shipp (Storm), Turner and Peters among others.

Sitting down with Collider primarily to promote his newest project, American Animals, Peters was asked about what fans can expect from Dark Phoenix. I think it’s gonna be darker than we’re used to. It’s gonna be a change, but it’s gonna be fun for everybody.

Obviously, the star couldn't talk about anything plot-related about the film but he teased of the tone of the next X-Men film and how it compares to other installments from the franchise.

I think it’s the classic X-Men: First Class tone, where there’s a bit of humor thrown in there, but it’s much darker than the previous one, Apocalypse. Apocalypse was the ‘80s, so there was a lot of room for goofy stuff in there. 

This one is a much more serious film about the internal struggle of Phoenix and Jean, so it’s a dramatic film. There’s nothing very comedic about it, other than the few moments that are in there. I think it’s gonna be a powerful one. It’s Dark Phoenix.

Peter's comments can be buy Dark And Darker Gold interpreted in several ways, but it's interesting that he'd compare Dark Phoenix's tone to First Class which had the most relaxed vibe among all three installments from the X-Men rebooted timeline.