Pendleton Ward Lumpy Space Princess Creator, Voice Jeremy Shada Finn Voice John DiMaggio Jake Voice Hynden Walch Princess Bubblegum Voice Tom Kenny The Ice King Voice Olivia Olson Marceline Voice Jackie Buscarino Susan Strong, Kara Guest Voice Niki Yang BMO Guest Voice Sharon Horgan Minerva Guest Voice Stephen Root Martin Guest Voice Laraine Newman Widow Guest Voice Kent Osborne Guest Voice, Writer Lennon Parham Guest Voice Fred Seibert Executive Producer Kelly Crews Producer Sam Alden Writer