Comic-Con: Watch the Trailer for FX's 'X-Men' Drama 'Legion'

The erstwhile Matthew Crawley is a long way away from Downton Abbey.

FX threw its hat into the superhero ring Saturday at San Diego Comic-Con when the network unveiled the first footage of its forthcoming X-Men drama series Legion. The footage was shown during a Marvel panel with chief creative officer Joe Quesada and was well received. 

Legion marks the latest Marvel TV series and first on basic cable. It joins ABC's Agents of SHIELD and Netflix's Luke Cage, Daredevil, Jessica Jones, Iron Fist, The Defenders and Punisher.

Dan Stevens, best known for his starring role on the first three seasons of Downton Abbey, will return to TV screens in Legion, based on the Marvel Comics character of the same name. Stevens plays David Haller, a man who is diagnosed with schizophrenia and learns that the visions and voices in his head might be more real than he once realized.

The Marvel character, created by legendary X-Men writer Chris Claremont and artist Bill Sienkiewicz, stands out as an improbable figure to build an entire show around. But the creative mind behind Legion knows a thing or two about improbable series: Noah Hawley, head writer and producer behind FX's award-winning Fargo, mashing the Coen Brothers' true-crime elements with some of the auteur filmmakers' more mystical interests (see: alien space-crafts hovering over the American Midwest in the middle of a gunfight). 

Expect that extraterrestrial event to only skim the surface of Hawley's whacked-out wheelhouse, based on the Legion footage released Friday.

In addition to Stevens, Legion features an all-star cast, including Fargo veterans Rachel Keller and Jean Smart as well as Parks & Recreation favorite Aubrey Plaza.

Stay tuned to for more coverage from San Diego.