Rurio is a male pheasant who served as one of Momotarō's animal companions during their legendary exploits in life. Following their defeat by Hoozuki, Rurio, along with Shiro the dog and Kakisuke the monkey, now serves in the Animal Hell division of the Japanese afterlife. They administer punishments to sinners condemned for animal cruelty, embodying ironic justice where tormentors of animals are tormented by them.

Rurio exhibits a serious demeanor, contrasting with his companions' more lighthearted or guilt-ridden traits. His personality includes a notable short temper, particularly when provoked. This is demonstrated when he violently headbutts the goddess Amanojaku after she intentionally irritates him during an interaction in Amanojaku's Den, a section of Hell dedicated to punishing contrary individuals. This incident occurs under the context of Amenosagume (Amanojaku) feeling a kinship with Rurio due to their shared connection to divine pheasants and the tragic fate of Urikohime, with Rurio's reaction underscoring his low tolerance for annoyance.