Armin Arlert hails from Shiganshina District in Wall Maria, orphaned young when his parents died exploring beyond the walls and raised by his grandfather. A forbidden book from his grandfather about the outside world ignited his intense curiosity and dreams of witnessing oceans and deserts, leading other children to bully him as a heretic. His frail build and timid nature forced reliance on childhood friends Eren Yeager and Mikasa Ackermann for protection, breeding lasting shame and inadequacy. He enlisted in the 104th Training Corps, graduating with unremarkable combat skills and physical stamina, ranking outside the top 10, yet showcasing exceptional strategic intellect. Physically slight at 163 centimeters tall—later 169—he had blonde hair in a bob or undercut, piercing blue eyes, and distinctive expressive eyebrows, consistently clad in standard military gear, including the Survey Corps’ green cape and brown boots during expeditions. Despite perceiving himself as weak, Armin repeatedly proved indispensable through tactical brilliance. He engineered the reclamation of Trost District’s supply depot, orchestrated the Female Titan’s capture, sealed Wall Rose’s breach, and masterminded the defeat of Bertholdt Hoover’s Colossus Titan at Shiganshina. The latter plan involved a near-fatal diversion that left him scorched by steam. With Commander Erwin Smith dying and only one Titan serum available, Captain Levi selected Armin—influenced by Eren’s pleas. Armin transformed into a Pure Titan, consumed Bertholdt, inherited the Colossus Titan, and reverted to human form. This act triggered profound psychological shifts. Haunted by guilt over Bertholdt’s death, Armin saw himself as both victim and perpetrator, later rationalizing morally ambiguous choices as inevitable. Inheriting the Titan’s destructive power and succeeding Hange Zoë as the 15th Survey Corps Commander thrust him into leadership, exacerbating his anxiety and self-doubt. As commander, he critically participated in the Raid on Liberio, where his Colossus Titan form annihilated the Marleyan fleet and city sections. During Eren’s global Rumbling, he confronted his friend, opposed the genocide, yet acknowledged shared responsibility for its 80% human toll, bearing the burden collectively while coordinating the alliance against Eren. Armin embodies complex dualities: kind-hearted and empathetic—visibly anguished after taking lives—yet hardened by experience and admiration for figures like Erwin Smith, believing major change demands sacrificing one’s humanity. He rejects absolute morality, viewing good and evil as relative, which enables ruthless strategies that unsettle peers. Eren and Mikasa consistently anticipated this capacity. His loyalty drives him to protect comrades like Jean Kirstein at great personal cost. His bond with Annie Leonhart evolved from mutual respect to romance, sustained by visits during her crystalline hibernation and their collaboration for peace. His Colossus Titan form mirrors Bertholdt’s: skinless, towering, with elongated limbs, exposed ribs, and a skeletal face, distinguished by defined lips, sunken muscular eyes, and a prominent windpipe. His earlier Pure Titan form displayed blond hair, a gaunt frame, and visible ribs.