This ethereal, three-hour biopic is the middle film in Hans-Jürgen Syberberg’s “German Trilogy” on the mythological foundations of the Third Reich. By fusing theater, music, and cinema, Syberberg conjures up Karl May (1842-1912), the immensely popular German author, who set many of his adventure novels in an idealized version of the American Wild West. His tales of the cowboy and the Ubermensch alike were beloved by many, including (Our) Hitler, who supposedly ordered his generals to read May works after defeats in the Russian campaign.