Levi Ackerman often formally referred to as Captain Levi , is the squad captain of the Special Operations Squad within the Survey Corps and is widely known as humanity's strongest soldier. He is usually either frowning or expressionless; that, plus his extremely calm demeanor, often makes it difficult for others to guess what he is thinking. Levi Ackerman is a fictional character from Hajime Isayama's manga series Attack on Titan.