Moriyama Koudai is Sunao's father, and is a folklorist. He has a childish personality and likes to play around constantly, which causes his son to not take him seriously in any situation. Koudai is almost always away on travel, something Sunao resents him for. Often, Koudai is beaten by Sunao for his immature behavior. He refers to Potemayo as "Mochi-Mochi."