Planet Kinniku (キン肉星, Kinniku-sei) is a planet from Kinnikuman and Kinnikuman Nisei, and is the homeworld of the Kinniku Clan. From a very young age, many clans wear masks that look so realistic that it could be mistaken for their face, in fact the face underneath is more human in appearance (i.e. Mantaro's large lips are part of the mask, his actual face has a normal mouth). The head fin shared among the planets inhabitants is part of this mask. The mask can never be removed—to lose one's mask is punishable by death.