Thief, a female character with brown hair, belongs to an adventuring quartet led by Hero and including White Mage and Archer. This group relentlessly pursues the dragon Letty during his quest for a home, materializing without warning wherever he attempts to settle. Acting as comical antagonists, the quartet operates from a self-righteous sense of justice that ignores others' situations. Though routinely defeated or repelled in confrontations, they persistently return to mount new attacks against Letty.

Thief's narrative function remains strictly tied to this group dynamic. Official materials—spanning the anime, manga, and related media—document no individual backstory, character evolution, or personal motivations for her. She maintains a static role without dedicated background exploration or development arcs, solely contributing to the party's recurring comedic disruptions.

Thief's relevance extends no further than these collective pursuits. Neither spin-off media nor supplementary materials expand her role, confining her involvement entirely to the quartet's endeavors against Letty.