David Haller's worst nightmare just became very, very real.

Wonder Woman actor Said Taghmaoui has been cast to play the role of Amahl Farouk on Legion, the comic book drama from FX and Fargo creator Noah Hawley, based on an obscure but vibrant corner of Marvel's X-Men universe. The news was announced Thursday at the show's official San Diego Comic-Con panel.

FX describes Farouk as a "villain with a thousand faces. In his real form, he is always nattily dressed. Dapper with a thin Clark Gable-style mustache. His eyes forever hidden behind a pair of ornate sunglasses. He was hip long before there was such an idea. He can seductively hold court on any topic and in any language, but his true passion lies in the singular timeless notion of power and amassing as much of it as possible.

"It is rumored he is the spawn of the first nightmare, which is fitting because fear is his weapon of choice in exposing weakness in others. To Farouk, fear equals weakness and he fears nothing. Which is why he takes such delight in seeing others squirm — a reminder he is more powerful than them."

Although Taghmaoui is new to Legion, Farouk is very much a known quantity. He has already appeared numerous times on the show, albeit with different names (like "Lenny") and faces (like "Aubrey Plaza"). He's alternately known as the Shadow King, one of the most powerful foes in the X-Men comics, and certainly one of the more elaborate villains from Marvel's mutant stable ever adapted for live-action.

Throughout the first season, Farouk haunted and terrorized virtually everybody in the Legion cast, most memorably David (Dan Stevens), the career mental patient who discovers he might not be insane, just an insanely powerful mutant. Frighteningly enough, Farouk rivals David's own telepathic abilities, which is why he spent so much of the young man's life living inside of his head.

As of the season two finale, David was finally free from Farouk, but at what cost? The long-lost mutant Oliver Bird (Jemaine Clement) was last seen hitting the open road as the new host of the Shadow King, with Plaza's Lenny riding shotgun. How does the inclusion of Taghmaoui as yet another face for Farouk impact both Clement and Plaza's work on the show? We'll have to wait for season two to find out.

For his part, Taghmaoui is already enjoying a strong year within the comic book genre, having appeared in Patty Jenkins' Wonder Woman as Sameer, one of the hero's key allies in World War I. The actor's many credits include roles in Three Kings, The Kite Runner, G.I. Joe: The Rise of Cobra and TV's Lost. He is repped by APA, Three Six Zero Group and Markham Frogatt & Irwin.

FX's Legion is expected to return for season two sometime in 2018.

Follow THR.com/Legion for more news, interviews and theories about the series.