Stevens will play David Haller – aka Legion, and the son of Charles Xavier in the original comics (as yet there’s no indication whether that link will be maintained for the series). According to Deadline, “Since he was a teenager, David has struggled with mental illness. Diagnosed as schizophrenic, he has been in and out of psychiatric hospitals for years. A haunted man, David is getting tired of finding his way back to sanity and is about to give up when he meets the girl of his dreams, a fellow patient. After the strange encounter, he’s confronted with the possibility that the voices he hears and the visions he sees might be real.”
Stevens will be joined by Aubrey Plaza as David’s friend Lenny, “who despite a life of drugs and alcohol abuse, knows that any day now her life is gonna turn around, which gives her the likeable energy of the impossible optimist despite her rough demeanour” while Jean Smart will play Melanie, “a nurturing, demanding therapist with a sharp mind and unconventional methods.” Rachel Keller was already cast as streetwise Syd.