Kate is a young girl in the Shadow family, a noble family. She is the main protagonist along with her "Living Doll", Emilico.
Kate is a very calm and intelligent young girl. At the beginning of the story she is very distant with Emilico although she cares about her. From the beginning of the story, we see that Kate suffers a lot because she is a shadow and her emotions cannot be easily understood. But with the help of Emilico, she becomes a little more open even if still a little distant with the other master shadows.
(Source: Shadows House Wiki)