Annie Leonhart, born in Marley, faced deportation to Liberio's internment zone after a blood test exposed her Eldian heritage. Adopted by Mr. Leonhart, she endured brutal combat training from early childhood to become a Warrior and secure her adoptive father's privileged status. This training culminated in Annie attacking him and leaving him permanently crippled—an act that paradoxically filled him with pride, leaving her emotionally detached and unable to value life or death. As a Marleyan Warrior candidate, Annie excelled in combat and inherited the Female Titan. Alongside Reiner Braun, Bertolt Hoover, and Marcel Galliard, she participated in military operations, including the destruction of a nation to demonstrate the Warriors' effectiveness. Selected for the Paradis Island mission to retrieve the Founding Titan, Annie infiltrated the island with her comrades. When Marcel died saving Reiner from a Pure Titan, Annie blamed Reiner's cowardice and advocated abandoning the mission. Reiner convinced her to continue under threat of Marleyan retribution. Annie transported the group to Wall Maria in her Titan form, attracting Titans that contributed to the district's fall. Posing as refugees from Wall Maria's destruction, Annie, Reiner, and Bertolt enrolled in the 104th Training Corps. Annie ranked 4th, noted for exceptional swordsmanship and unmatched Muay Thai-inspired hand-to-hand combat skills. Her aloof, apathetic demeanor and lone-wolf tendencies masked a pragmatic worldview; she openly criticized military systems and Marleyan propaganda. Despite isolation, she showed rare respect for individuals driven by duty like Marlowe Freudenberg. Unexpected moments of connection surfaced, notably her offer to teach Eren Jaeger her fighting style—one of her few genuine smiles. During the Battle of Trost, Annie assisted in reclaiming headquarters and witnessed Eren's emergence from his Titan. She later expressed guilt handling corpses, hinting at unresolved conflict. As the Female Titan, she conducted espionage, including killing captured Titans Sonny and Bean to hinder research. Her covert activities culminated in the 57th Expedition, where she transformed to capture Eren. She killed numerous soldiers and civilians but spared Armin Arlert twice, later admitting this tactical error stemmed from lingering fondness. Cornered in Stohess District, she fought Eren's Titan form and crystallized herself to avoid capture, entering a comatose state. Confined underground for four years, Annie remained crystallized until the Yeagerist uprising created chaos, enabling her escape. Post-awakening, her priorities shifted: she openly acknowledged her "irredeemable sins" to Hitch Dreyse and allied with former enemies—including Armin and the Survey Corps—to stop Eren Yeager's Rumbling, driven solely by reuniting with her father. She expressed gratitude to Armin for his visits during confinement, though she still viewed herself as a monster. Her combat skills remained integral to the alliance, utilizing the Female Titan's speed, agility, and selective hardening against Yeagerists and Pure Titans. The Female Titan's capabilities included attracting nearby Titans via screams—a double-edged tactic risking attacks on herself. She hardened specific body parts for offense or defense, demonstrated when creating crystalline structures for climbing or self-preservation. Her Titan form mirrored her human physique, featuring exposed musculature and enhanced flexibility, distinguished by human-like teeth and lips.