Annie Leonhart is a key character in the anime series Shingeki no Kyojin, also known as Attack on Titan. She is a member of the Military Police Brigade and is later revealed to be the Female Titan, one of the Titans with the ability to transform from human to Titan form. Annie is known for her exceptional combat skills and stoic demeanor. Her role in the series is pivotal as she serves as an antagonist during the first season, creating significant conflict and tension among the protagonists while also providing insight into the mysterious nature of the Titans.