Kate is a young girl in the Shadow family, a noble family. Her "Living Doll" is Emilico. Like the rest of the Shadow family, Kate is a shadow. Her whole body including her hair is black. She wears a red dress with a white frill underneath. She is a very calm and intelligent young girl.

Season One Spoiler
At the beginning of the story she is very distant with Emilico although she cares about her. She apparently suffers a lot because of a shadow and her emotions are not easy to understand. But with the help of Emilico, she opens up more socially, though is still quite distant with the other master shadows. Kate is also against the illustrious Grandfather and is organizing a revolution against him.