Annie Leonhardt (アニ・レオンハート Ani Reonhāto?) is a member of the 104th Trainees Squad who enters the Military Police.
Along with Bertoldt and Reiner, she is a person that possesses the ability to transform into a Titan and serves an as-yet unrevealed group. She comes from a mysterious homeland outside the Walls, and was on a mission to infiltrate the military in search of something referred to as the "Coordinate". Her efforts to kidnap Eren reveal the existence of enemy agents within the military, and leads to her eventual capture.
Annie is considered to be isolated, exclusionary type and friendships don't come to her easily. She is apathetic and somnolent with little desire to put in any effort into meaningless disciplines or activities, and instead focuses exclusively on making it into the Military Police to obtain an easy life. Yet, somehow she does seem to hold some strange fascination and even feelings of respect towards people that hold a deep sense of duty and righteousness -- in those people who do care and who can devote their lives and even die for causes they believe in.
Annie genuinely smiles as she expresses her interest in teaching Eren her techniquesDespite Annie's usual cold and calm demeanor, she has been shown to emote her feelings in various ways. She was clearly angered when Reiner teased her about her constant avoidance in hand-to-hand combat training. She has shown genuine surprise on various occasions, especially if one considers her expressions during her rampage as the Female Titan in the 57th Expedition of the Scouting Legion. Despite her seeming callousness, she has expressed a level of guilt and shock, most notably when apologizing to a certain corpse after the battle of Trost. Annie is also known to be very dedicated in her mission as a Titan Shifter, to the point that she shed tears when she failed to capture Eren. Though she is seemingly indifferent towards her capability as a competent hand-to-hand combat fighter, she remains proud of her skills and even seems to enjoy the very notion of fighting as deduced by Eren. The only time that she is seen as genuinely smiling in a caring manner is when she expressed a curious interest in teaching Eren how to fight in her unique fighting style.