Robert Kirkman Creator Cory Walker Creator Ryan Ottley Creator Steven Yeun Mark Grayson Voice J.K. Simmons Omni-Man Voice Sandra Oh Debbie Grayson Voice Seth Rogen Allen the Alien Voice Mark Hamill Art Rosebaum Voice Walton Goggins Cecil Stedman Voice Jason Mantzoukas Rex Sloan, Rex Splode Voice Mae Whitman Fightmaster & Dropkick Voice Zazie Beetz Amber Bennett Voice Max Burkholder Oliver Grayson Voice Chris Diamantopoulos Doc Seismic, Donald Ferguson Voice Michael Dorn Battle Beast Voice Grey DeLisle Amanda, Shrinking Ray Voice Gillian Jacobs Samantha Eve Wilkins, Atom Eye Voice Melise Kate Cha, Dupli-Kate Voice Khary Payton Black Samson Voice Zachary Quinto Rudy Conners, Robot Voice Andrew Rannells William Clockwell Voice Kevin Michael Richardson Mauler Twins, Monster Girl Voice