Gruach

 was the wife of Macbeth of Scotland. She encountered the Ninth Doctor after praying to ward of dark spirits who rescued her from the Fuath. She thought that he was a blue man. She did not like her husband. She explained the situation of the changelings to the Doctor and that she wanted him to sort out the problem. She wanted to care for them. Her mothering instinct stopped the Fuath. (AUDIO: The Curse of Lady Macbeth)