Beatrice, an artificial spirit forged by Echidna four centuries before her story unfolds, guarded the Forbidden Library under her creator’s command, enduring isolation while awaiting the prophesied arrival of "that person" destined to release her. Bound to a pocket dimension linked to Roswaal’s mansion via spatial magic, her solitary vigil concluded when Subaru Natsuki, a tenacious human, breached her emotional defenses, forging a contract that freed her from eternal duty. Resembling a petite girl of eleven or twelve, Beatrice boasts cream-colored twin drills with pink tips and sky-blue eyes marked by intricate pink butterfly motifs—subtle echoes of Echidna’s design. Her static form dons a frilly pink dress with white detailing, striped tights, and a diminutive crown, though her attire occasionally shifts. Aloof yet vulnerable, she masks solitude with third-person speech and a habit of ending phrases with "I suppose," projecting haughtiness while reluctantly aiding others. Initially dismissive, she repeatedly heals Subaru despite their clashes, her icy demeanor thawing until she abandons her post to become his contracted spirit, sustained by his mana. A shadow magic virtuoso, Beatrice manipulates space to warp the library’s structure, conjure endless corridors, and halt time. Her arsenal includes healing spells, sensory-deprivation techniques like Shamac, and curse-neutralizing skills vital to Subaru’s survival. Though her power once matched elite mages, post-contract limitations curb her prowess, offset by her ability to drain mana through touch. In crossover scenarios, she remains consistently sharp-tongued, rebuffing figures like Vooren Grantz during challenges and bristling at condescension. Her bond with Overlord’s Mare defies expectations, as she warms to him despite initial surprise at his identity. Evolving from centuries of solitude, her pact with Subaru catalyzes integration into wider conflicts and alliances. This arc traces her shift from rigid duty to embracing interdependence, balancing lingering pride with emergent tenderness—a testament to her growth from isolated guardian to connected ally.