Bethi is the favorite Asheth Temple Cat of Millie in her role as incarnated Goddess Asheth. When we first meet Millie, she tells Christopher that Bethi is expecting kittens. Later, Millie is already beginning to suspect that bad things are in store for her, since the Goddess' incarnations are always young girls, and she is growing older than feels safe. She asks Christopher for advice in handling her worries, and he tells her to ask Asheth to give her some kind of sign or portent. Millie does so, and is told by the Goddess to wait several hours for her to manage the portent. After the wait, Millie discovers that Bethi's kittens have been born, but Bethi has died in the process, which convinces her that her future is to be killed so that the next young girl can become the incarnation.
One of Bethi's kittens, Proudfoot, is brought by Millie to Chrestomanci Castle when she flees there to live in Christopher's world.