Levi Ackerman serves as the captain of the Special Operations Squad within the Survey Corps and is widely recognized as humanity's strongest soldier. He was born and raised in the underground city, a squalid and violent district beneath the capital. His mother, Kuchel Ackerman, was a prostitute who died from illness when he was very young. After her death, his maternal uncle Kenny Ackerman took him in for a time, teaching him survival skills, knife fighting, and close-quarters combat before abandoning him. Levi then lived as a thief and leader of a small criminal group in the underground, alongside his companions Furlan Church and Isabel Magnolia. Their activities caught the attention of Commander Erwin Smith, who offered them amnesty in exchange for joining the Survey Corps. During their first expedition, both Furlan and Isabel were killed by Titans, an event that shattered Levi but also led him to commit himself to Erwin's cause. He carried out the mission of the Survey Corps from that point forward, driven by a desire to give meaning to the sacrifices of those who fell around him.

Levi's personality is defined by a cold, disciplined, and perfectionist demeanor. He maintains strict standards of order and cleanliness, an obsessive tendency that stems from his traumatic upbringing in filth and chaos. This need for control extends to his leadership style: he demands absolute excellence from his subordinates, tolerates no insubordination or sloppiness, and makes decisions with cold rationality. Despite his abrasive exterior, he possesses a deeply buried sense of empathy and loyalty. He rarely expresses emotion openly, but his actions are consistently motivated by a commitment to protecting his comrades and honoring promises made to the dead. His most significant driving force is his promise to Erwin Smith to kill the Beast Titan, Zeke Yeager, which he ultimately fulfills after years of perseverance.

Within the story, Levi begins as a feared and respected captain assigned to guard and potentially execute Eren Yeager if the boy loses control of his Titan powers. He leads his elite squad through numerous high-risk missions, including the retaking of Wall Maria, the battle against the Female Titan, and the confrontation with the Beast Titan. His tactical acumen and unmatched combat prowess make him a pivotal figure in nearly every major turning point of the narrative. After Erwin's death, Levi carries the weight of command under Hange Zoë, and later, despite sustaining severe injuries from Zeke's explosion, he remains active in the final battle against Eren, ultimately killing Zeke and ensuring the end of the Titan curse.

Key relationships shape Levi's character arc. His bond with Erwin Smith is the foundation of his loyalty; he never questions Erwin's orders, even when they require sacrificing soldiers, because he trusts Erwin's vision. His relationship with his uncle Kenny is fraught with bitterness and understanding; Levi eventually confronts Kenny and learns the truth about the Ackerman bloodline, which grants its members enhanced physical abilities and a predisposition to protect specific individuals. Levi shares this bloodline with Mikasa Ackerman, and while he treats her with his usual sternness, he acknowledges her strength and potential. His interactions with Eren grow increasingly tense as Eren's path diverges from the Survey Corps' mission, and Levi eventually sides against Eren and his allies. He also develops a grudging respect for certain enemies, such as Pieck Finger, for their intelligence and capability.

Levi's abilities are extraordinary even by the standards of elite soldiers. He is an unparalleled master of the omni-directional mobility gear, able to perform maneuvers that seem physically impossible. His speed, precision, and lethal efficiency allow him to single-handedly take down multiple Titans in seconds. He is also highly skilled in hand-to-hand combat, a result of his upbringing and Kenny's training. His strategic mind enables him to read battlefields instantly and make split-second decisions that often turn the tide. The Ackerman bloodline grants him heightened strength, reflexes, and instincts, which he honed into an almost supernatural level of combat effectiveness. Despite his small stature, he uses his size to his advantage, moving with remarkable agility.

Throughout the series, Levi undergoes a subtle but meaningful development. He begins as a cynical survivor focused solely on his immediate missions, but over time he becomes a symbol of resilience and hope for the soldiers around him. The losses he endures—especially the death of his original squad, the sacrifice of Erwin, and the betrayal of Eren—deepen his resolve rather than break it. After being permanently crippled by Zeke's explosion, he accepts his new limitations and continues to support his allies in a non-combat role. His final act is to fulfill his promise to Erwin, after which he retires to a quiet life, haunted but at peace. His legacy is that of a soldier who never wavered, who carried the memories of his fallen comrades, and who fought until the very end to uphold the ideals of freedom and humanity.