Guest Stars Donna Kimball voices Aughra Jason Isaacs voices The Emperor Keegan-Michael Key voices The Ritual Master Mark Hamill voices The Scientist Gugu Mbatha-Raw voices Seladon Benedict Wong voices The General Caitríona Balfe voices Tavra Simon Pegg voices The Chamberlain Victor Yerrid voices Hup Neil Sterenberg voices The Scroll Keeper Awkwafina voices The Collector Kevin Clash voices Gruenak #1 Harvey Fierstein voices The Gourmand Warrick Brownlow-Pike voices Podling Servant #1 Warrick Brownlow-Pike voices Red-Haired Paladin Lena Headey voices Maudra Fara Ólafur Darri Ólafsson voices The Archer Neil Sterenberg voices Gruenak #2 Ralph Ineson voices The Hunter Alice Dinnean voices The Ornamentalist Andy Samberg voices The Heretic Bill Hader voices UrGoh the Wanderer James Dreyfus voices Lath'N Louise Gold voices Maudra Argot Charlie Condou voices Mitjan Beccy Henderson voices Bobb'N Theo Ogundipe voices The Sanctuary Tree