Shinobibe Genryūsai is a human cursed into the form of a monkey by Doakutara, the mountain's ruler. Defeating this entity offers the only known path to breaking the curse and restoring his human body. He is the biological father of Himiko Shinobibe, who holds him in deep respect and explicitly acknowledges his mastery of ninjutsu. Genryūsai wears traditional shinobi armor complemented by a distinctive Kabuto-style paper hat. His speech is marked by the unique habit of ending sentences with the suffix "-yay".