Pendleton Ward Shelby Creator, Guest Voice Jeremy Shada Finn Voice John DiMaggio Jake Voice Hynden Walch Princess Bubblegum Voice Tom Kenny The Ice King Voice M. Emmet Walsh Cosmic Owl Guest Voice Kumail Nanjiani Prismo Guest Voice Ron Perlman The Lich Guest Voice Miguel Ferrer Grod, Death Guest Voice Cole Sanchez Party God, Cloud People Guest Voice, Writer Steve Little Peppermint Butler Guest Voice Tom Herpich Clock Face, Void Caster Guest Voice, Writer Polly Lou Livingston Tree Trunks Guest Voice Stephen Root Martin Guest Voice Ethan Maher Sweet P Guest Voice Fred Seibert Executive Producer Kelly Crews Producer Andy Ristaino Writer Steve Wolfhard Writer