OVA
Description
Armin Arlelt, a member of the 104th Cadet Corps, grew up in Shiganshina District alongside childhood friends Eren Jaeger and Mikasa Ackermann. His grandfather's forbidden book about the outside world sparked Armin's intense fascination with life beyond the Walls, a passion shared with Eren that drew bullying from other children who branded him a heretic. Physically frail and timid, he frequently relied on Eren and Mikasa for protection, fostering persistent self-doubt and feelings of being a burden.

During cadet training, Armin viewed himself as weaker than peers but honed exceptional strategic thinking and analytical abilities. He devised creative, underhanded tactics to expose Reiner Braun and Bertholdt Hoover as Titans, manipulated Annie Leonhart into revealing her Female Titan identity, and formulated critical diversionary plans. Despite growing competence, he remained self-critical and anxious in leadership roles.

Armin displayed fierce loyalty and selflessness, volunteering for sacrifice during a mission where he, Jean Kirschtein, and Reiner decided who would be stranded without a horse. He later sustained fatal burns creating a diversion against Bertholdt's Colossal Titan at Shiganshina. Captain Levi chose to revive him with Titan serum over Commander Erwin Smith, leading Armin to inherit the Colossal Titan by consuming Bertholdt—an act that intensified his survivor's guilt and internal conflict over brutality.

In the OVA "A Sudden Visitor: The Torturous Curse of Adolescence," Armin joined a mock defense drill in Trost District. He assisted Jean Kirstein in a cook-off challenge against Sasha Braus, orchestrated by Commander Dot Pyxis, and hunted a colossal boar with Jean and Annie Leonhart, attempting to lure Sasha with potatoes. His physical limitations surfaced when he injured his legs fleeing Jean's meat-stealing scheme, preventing further participation. Throughout, he acted as a voice of reason, cautioning against excessive training and showing aversion to morally questionable actions.

Post-Shiganshina, Armin became the 15th Commander of the Survey Corps after Hange Zoë's death. His inherited Colossal Titan form differed from Bertholdt's, appearing skinless with exposed ribs, elongated arms, a visible windpipe, lips, and a somber expression. During the final conflict against Eren's Rumbling, an Okapi Titan devoured Armin, sending him to the Paths dimension. There, he convinced Zeke Yeager to halt the Rumbling and coordinated past Titan shifters to stop Eren. After Eren's defeat, Armin served as a peace ambassador between Paradis Island and the outside world.

Armin embraced moral relativity, rejecting absolute good or evil. He believed overcoming monstrous threats required sacrificing humanity, admiring leaders like Erwin Smith and Dot Pyxis for such resolve. Yet his empathy and guilt over killing to protect comrades highlighted a constant struggle between pragmatism and compassion, defining his leadership and evolution.