Three Nanba prison guards who serve under Head Warden Momoko Hyakushiki - Kiji Mitsuba, Kenshirou Yozakura and Samon Gokuu - are named from a Japanese folktale about Momotaro, a folk hero born from a peach ("Momo" in the Head Warden's name), who befriended a pheasant, a dog and a monkey (respectively "kiji", "ken" and "samon" in their names). Each has decorations on their uniform referencing a bird, a dog, and a monkey.