Rumillion Shine, called Rumi, is an elf magician whose village was consumed by a vast forest fire. This tragedy separated her from family and friends, leaving her alone until Pastel's traveling party discovered her weeping beside the road to Evelyn. She joined their group to search for her lost kin, later reuniting with her mother during the journey.

Her path to adventuring began unexpectedly when Clay, mistaking her for an exam candidate, registered her alongside Pastel. Unlike Pastel, who failed both the written and practical adventurer exams, Rumi passed both on her initial attempt. Her written test success came by chance, correctly selecting one of two answers to score above the passing mark.

Rumi possesses fluffy silver-blonde hair and large blue eyes, giving her an angelic appearance. She exhibits an innocent personality and a childlike manner of speaking, notably referring to Pastel as "Paaru," whom she regards as an older sister figure within the group. A defining trait is her gluttony, frequently expressed through her catchphrase, "I'm starving."