BEGIN SLIDESHOW Legion Season 2 promo reminds you that you’re delusional FX Networks has released a new promo for the upcoming second season of Legion which you can check out in the player below! The all-new episodes premiere on Tuesday, April 3. Based on the Marvel Comics by Chris Claremont and Bill Sienkiewicz, Legion is the story of “David Haller” (Dan Stevens), a man who believed himself to be schizophrenic only to discover that he may actually be the most powerful mutant the world has ever seen. From childhood, David shuffled from one psychiatric institution to the next until, in his early 30s, he met and fell in love with a beautiful and troubled fellow patient named “Syd” (Rachel Keller).