FOLLOW @legionfx; 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 is 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 …