Riko is the only child of the legendary cave raider Raiza "The Annihilator." When Riko was two, her mother went missing during a quest to the bottom of the Abyss, since then Riko lived in Beruchoro Orphanage, studying to become a cave raider herself.

By the age of twelve she's attained the rank of an apprentice which gives her rights to wear a red whistle and explore the shallowest levels of the Abyss. She dreams of attaining the white whistle rank (the highest among cave raiders) and following her mother to the bottom of the Abyss.

Riko is a good-natured and energetic child. She has a quick and inquisitive mind and tries to gather and properly organize all the information available on the subjects that interest her. Riko is resilient and stubborn and although, due to the slight build, she's not much of a brawler, her ability to keep a cool head under pressure and make rational decisions in the heat of battle allows her to successfully tackle most dangers the Abyss has to offer. She's also very good at cooking.