Brigitte acts as fairy companion to Kakka Arthur, a wielder of a grimoire-form Excalibur variant. She provides dedicated support to her assigned Arthur. Her personality buzzes with energetic informality, often addressing him casually—a stark contrast to Kakka Arthur's haughty, intellectually driven demeanor.

She exhibits an enthusiastic, almost overeager approach, reminiscent of an eager junior. Despite Kakka Arthur's outwardly condescending and hyper-logical nature, Brigitte stands among the few individuals before whom he lowers his guard. She perceives him as possessing childlike, unreliable tendencies yet remains deeply invested in seeing him mature. Their dynamic involves her providing grounding support, counterbalancing his lack of practical battlefield experience.

Visually, Brigitte is defined by waist-length blue hair and green eyes. She operates within the narrative focused on multiple Arthurs hunting aberrant Excaliburs that distort history.