Annie Leonhart, born to an adoptive father in Liberio's internment zone following a blood test confirming her Eldian blood, endured harsh combat training from childhood. Her father aimed to secure their status by molding her into a Warrior for Marley, forging her into an emotionally detached individual indifferent to life and death. In retribution, she attacked him, leaving him permanently crippled, then departed for Warrior training. Excelling in combat, Annie inherited the Female Titan and joined Warriors Reiner Braun, Bertolt Hoover, and Marcel Galliard in devastating Marleyan military campaigns. Deployed to Paradis Island in 845 to retrieve the Founding Titan, she used her Titan form during Shiganshina's fall to lure Titans toward the wall, causing mass civilian deaths—including Eren Yeager’s mother. Posing as a refugee, she enrolled in the 104th Training Corps, ranking fourth. Her martial prowess and tactical skill stood out, yet she maintained an aloof demeanor to avoid compromising her mission. Though rarely emotive, she showed fleeting interest in teaching Eren her fighting style. Despite efforts to isolate herself, she spared Armin Arlert during expeditions and expressed visible remorse after Marco Bott’s death. As the Female Titan, Annie wielded heightened agility, speed, skin-hardening abilities, and a scream to attract Titans. During the 57th Expedition, she systematically slaughtered Survey Corps members to capture Eren. Exposed, she crystallized herself into an indestructible shell to evade interrogation, remaining comatose and guarded underground for four years. Awakening during a clash between the Survey Corps, Yeagerists, and Marleyan forces, Annie escaped. Her demeanor shifted: she allied with former enemies like Armin and the Survey Corps to halt Eren Yeager’s genocidal Rumbling. She confessed her unforgivable actions to allies such as Hitch Dreyse and thanked Armin for his visits during her confinement. Though joining the alliance, she saw herself as a monster, driven chiefly to reunite with her father—a goal achieved when she rescued him from Liberio amid the Rumbling. The OVA *Lost Girls: Wall Sina, Goodbye* delves into her moral conflict before her Female Titan reveal. Tasked with investigating a nobleman’s missing daughter, she confronts collateral damage from her actions, mirroring her internal struggle between duty and humanity.