The Chrestomanci Quartet (Charmed Life, Witch Week, The Magicians of Caprona, The Lives of Christopher Chant)

Gwendolen Chant and her brother Cat find the Chrestomancie Castle family's magic powers difficult to counter with the inferior powers of the Coven Street witches. After two centuries of feuding the powers of the two families of magicians in mythical Caprona are too weak to stop an incipient war, but the younger members of the families find a way.