Roberta Xerth is the head of the Office of Special Services. She is possibly the first werewolf to hold such a high-ranking government position. Xerth favors a rather brutal policy. She instructs her agents to kill any Dark wizards without question. Xerth is rather sensitive about the fact that she is a Muggle-born, and has taken steps to conceal her blood purity. She has also managed to keep the fact that she is a werewolf a total secret, even from her lover. Xerth has been having an affair with the much younger Raymond Frisk, the head of the Office of Secrecy, since 1989.