Precia Testarossa was a preeminent scientist focused on mana theory, dimensional teleportation, and mass waste disposal, renowned for her exceptional ability to manipulate external mana sources. Her early life featured significant academic achievements, though marked by social awkwardness and intense research focus. She bore a biological daughter, Alicia Testarossa, whom she deeply loved. A catastrophic accident during a high-pressure research project killed Alicia, triggering Precia's descent into madness and an obsessive quest for resurrection. Consumed by guilt and grief, Precia launched the illegal "Project Fate," collaborating with scientist Jail Scaglietti on cloning and resurrection research. She created an artificial human clone of Alicia, implanted with Alicia's memories, naming her Fate Testarossa. Precia initially tried to accept Fate as her daughter but grew increasingly hostile and abusive when Fate failed to match her idealized image of Alicia. She assigned her familiar, Linith, to train Fate in combat magic and provided the Intelligent Device Bardiche. After dismissing Linith, Precia subjected Fate to physical and emotional torture, demanding absolute obedience. Residing within the interdimensional fortress "Garden of Time," Precia leveraged its potent mana reactor to amplify her magic, earning her a Conditional-SS mage rank from the Time-Space Administration Bureau (TSAB). Her ultimate goal required collecting 21 ancient artifacts, the Jewel Seeds, to power a dimensional jump to the mythical realm Al-Hazard. She believed lost technology there could fully resurrect Alicia. She commanded Fate to retrieve the Jewel Seeds from Earth, leading to conflicts with Nanoha Takamachi and the TSAB. As the TSAB closed in, Precia revealed Fate's origin as a failed clone, declared her hatred, and dismissed Fate as a mere tool. Activating nine Jewel Seeds, she attempted the jump to Al-Hazard, causing a dimensional collapse that destroyed the Garden of Time. Refusing rescue, she chose to perish alongside Alicia's preserved body, vanishing into interdimensional space. Her fate is officially listed as Missing in Action. Her legacy endures through Fate's struggles with identity and artificial origins, influencing Fate's interactions with other artificial beings like the Wolkenritter and Erio Mondial. In the *A's* season, a hallucination of a kind, nurturing Precia appears in Fate's dream, symbolizing her unfulfilled desire for maternal love. The *StrikerS* manga further explores her impact through Fate's reflections on abuse and artificial life. In alternate continuities like *INNOCENT* and *Brave Duel*, Precia appears as a mentally stable, doting mother to both Alicia and Fate, co-managing a hobby shop with Lindy Harlaown. This version lacks the trauma of Alicia's death, showcasing a cheerful and supportive personality. The *Gears of Destiny* video game features a non-canon "Dark Fragment" incarnation based on Fate's memories. Precia wielded purple-hued Midchildan magic, specializing in lightning-based attacks like "Photon Bullet," "Photon Burst," and area-of-effect spells such as "Thunder Rage." Her defenses included "X Defender" barriers. She utilized an unnamed Device, often in staff form, to channel spells and maintain clairvoyance to monitor Fate. Her unique ability to harness the Garden of Time's reactor enabled large-scale feats like cross-dimensional assaults and simultaneous activation of multiple Jewel Seeds without physical corruption.