Fie Claussell is a member of Class VII, and a major character in the Cold Steel arc. Fie Claussell grew up not knowing her parents, and ended up wandering by herself, usually battlefields. She was picked up by a Jaeger group, and grew up there with the Jaeger King, the leader of the Jaeger group, and the other members. One day, the Jaeger King died in a battle against the leader of a rival Jaeger group, and the group disbanded. Fie wandered by herself for a while, not knowing what to do, when Instructor Sara found her and took her in, giving her the chance to be at Thors Military Academy. Fie starts out as a very reserved girl, not saying more than what needs to be said. However, over the course of the game, she opens up more, having a more playful sense, and it usually ends up as her poking fun at the others, and says too much information at times, possibly knowing full well the effect it could have.

Fie has a higher pitched voice, having a bored tone with her voice in most cases, and a more condenscending/mocking tone the rest of the time. She isn't a very loud character, and her non-battle lines consist of emotions involving content, surprise, and natural.