Legion is an American cable television series created for FX by Noah Hawley, based on the Marvel Comics character David Haller. It is connected to the X-Men film series, the first television series to do so, and is produced by FX Productions in association with Marvel Television, The Donners' Company, Bad Hat Harry Productions, Kinberg Genre, and 26 Keys Productions. Hawley serves as showrunner on the series.
"The Legion pilot introduces the story of David Haller, a man who may be more than human and who has struggled with mental illness since his teenage years. Diagnosed as schizophrenic, David has been in and out of psychiatric hospitals for years. But after a strange encounter with a fellow patient, he is confronted with the possibility that the voices he hears and the visions he sees might be real. In the comics, David is the son of X-Men founder Charles Xavier (aka Professor X) and Israeli Holocaust survivor Gabrielle Haller. The character first appeared in New Mutants No. 25 in March 1985."  The series will not take place in the X-Men cinematic universe.
- Dan Stevens as David Haller / Legion
- Rachel Keller as Syd, the female lead
- Aubrey Plaza as Lenny, Haller's best friend
- Jean Smart as Melanie, Haller's therapist