OVA
Description
Born in Liberio's internment zone to Eldian mother Karina Braun and a forbidden Marleyan father he never met, Reiner Braun pursued Warrior candidacy driven by his mother's belief it would earn them honorary Marleyan status and reunite the family. He struggled physically and academically in training, overshadowed by peers Annie Leonhart in combat and Bertholdt Hoover in marksmanship, yet persisted out of loyalty to Marley and a desperate desire for his father's acceptance – a hope shattered when his father rejected them as "Eldian devils." Reiner inherited the Armored Titan at ten after Marcel Galliard manipulated the selection over his own brother, Porco.

In 845, Reiner infiltrated Paradis Island alongside Bertholdt, Annie, and Marcel to reclaim the Founding Titan. Marcel's sacrifice to save him from a titan attack traumatized Reiner and fueled intense guilt. Assuming leadership, he compelled Annie and Bertholdt to continue the mission, breaching Wall Maria and causing mass casualties, including the death of Eren Yeager's mother. Joining the 104th Cadet Corps, Reiner graduated second in his class. To cope with betraying Paradis, he adopted a dissociative "soldier" persona modeled after Marcel, becoming a protective, dependable figure to cadets like Eren, who saw him as an older brother. This fractured after witnessing Marco Bodt's murder, plunging Reiner into severe dissociative identity disorder, swinging between Warrior and soldier identities.

Reiner's instability peaked during the Shiganshina clash, where he revealed his identity as the Armored Titan to Eren. Following Bertholdt's death and Annie's capture, he returned alone to Marley. By 854, serving as Vice Captain of the Warrior Unit, Reiner battled depression, PTSD, and suicidal ideation stemming from his actions on Paradis. Physically gaunt with a goatee and longer hair, he prioritized protecting his family and younger Warriors like Falco Grice and Gabi Braun despite profound self-loathing. His tactical acumen remained, evident when he deciphered Zeke Yeager's covert warnings about Marleyan surveillance. Confronting Eren during the battle for Liberio, Reiner failed to stop the Rumbling, reinforcing his own sense of failure.

Reiner possesses blond hair, hazel eyes, a tall stature, and broad shoulders; post-timeskip weight loss rendered his features more defined. His 15-meter Armored Titan form is covered in hardened plates except for exposed muscles behind joints and cheeks, exhibiting high agility despite its weight and the ability to harden extremities into claws for climbing. His personality shifted from a meek child to a guilt-ridden adult, marked by conflict between loyalty to Marley and empathy for Paradis citizens he once deemed "devils." Bonding with cadets revealed their humanity, yet he continued his mission out of duty to family. His later actions aimed to prevent suffering for younger generations, though he remained haunted by his role in Eren's mother's death.