Anthea Tesdinic is Conrad's older sister. She has left home a few years before the story begins. She has dark hair, is considered by the adults around Conrad to be quite good-looking, and she has good academic skills, since she is able to be accepted and financially supported at University based on an examination she studied for and took.
At University, on the first day of magic class, she meets a young man who is going to be very important in her life. Like Conrad, she has had to deal with a father who died in her childhood, an absent-minded, neglectful mother, Franconia Grant, the feminist writer, and an uncle who is lazy, manipulative, secretive, and basically a scoundrel. In order to escape the servitude he presses her into, she is forced to finagle her way into the scholarship and then leave before her uncle can do anything to stop her.
Although she is gone from Conrad's home above the bookshop, she reappears later in the novel Conrad's Fate , and it is a very positive thing for both of them that she does so.