adopted by Kipo. Lio Oak (voiced by Sterling K. Brown) – Kipo's father, a scientist, and teacher of their underground community. He and Song were originally working for Dr. Emilia to turn mutes back into normal animals so humanity could reclaim the surface. Hugo "Scarlemagne" Oak (voiced by Dan Stevens) – A deranged, flamboyant, power-hungry mandrill and Kipo's adoptive older brother. He seeks to create a mute-only utopia and rule Las Vistas with an army of enslaved humans. Due to human experimentation, the pheromones in his sweat can control primate minds. Song Oak (voiced by Jee Young Han) – Kipo's mother and Lio's wife who originally worked with him to revert mutes back into normal animals before they changed their minds; thought to be deceased, she is later revealed to be alive. Dr. Emilia (voiced by Amy Landecker) – A cold-hearted, manipulative, remorseless human scientist who wants to end the mutes' existence. Supporting Molly Yarnchopper (voiced by Lea Delaria) – A Timbercat and Yumyan Hammerpaw's second-in-command. Yumyan Hammerpaw (voiced by Steve Blum) – Axe Lord of the Timbercats. His name is a parody of the tall tale character Paul Bunyan. Cotton (voiced by Grey Griffin) – Rocker leader of the Umlaut Snakes from Cactus Town. Good Billions and Bad Billions (voiced by John Hodgman and GZA/Guy Lockard) – Astronomer co-leaders of the Newton Wolves. Jamack (voiced by Jake Green) – A Mod Frog and enemy of Kipo after she caused him to be banished from his pack, but later becomes an ally. Tad Mulholland (voiced by Michael-Leon Wooley) – A sentient colony of tardigrades who traps others in dream worlds. Hoag (voiced by Jeff Bennett) – A member of Kipo's underground community and Doag's father. Troy Sandoval (voiced by Giullian Yao Gioiello) – A boy from Kipo's underground community and Benson's boyfriend. Asher and Dahlia Berdacs (voiced by River Butcher and Fryda Wolff) – Twin siblings from Kipo's underground community. Asher is non-binary while Dahlia is female. Amy and Brad (voiced by Avrielle Corti and Ace Gibson) – A pair of rats who manage an amusement park called Ratland. Zane and Greta (voiced by Carlos Alazraqui and Anna Vocino) – Dr. Emilia's assistants. Roberto Sandoval (voiced by Antonio Alvarez) – Troy's father. Fun Gus (voiced by Jack Stanton) – A sentient mold with a child-like personality. Label (voiced by Betsy Sodaro) – A Fitness Raccoon. Mrs. Sartori (voiced by Grey