Mimi Joyman is a human student at the girls' college attended by Tiara during her undercover mission on Earth. She forms part of a close-knit trio of classmates with Apolline Faria and Susanna White, the group that befriends Tiara soon after her arrival. Known throughout the school by the nickname "Beautiful Rose," Mimi carries a reputation for sharp sarcasm. She projects an aura of vanity and arrogance, consistently displaying eagerness and self-importance in her interactions. Her distinctive features include dark brown hair and striking violet eyes.

Entirely ordinary and possessing no magical abilities, Mimi remains oblivious to Tiara's true identity as a Guardian World agent and the mission concerning the Throne of Yord. Her existence is firmly rooted in the mundane reality of school life, serving as a counterpoint to the supernatural events surrounding Tiara. Mimi experiences no significant background development, character evolution, or involvement in the central plot across the OVA episodes or related media.