Margot Castile was the queen consort of King Cassius Stirling II and the mother of his three children: Letholdus III, Stephen, and Odette.
Born in Zantium, she was betrothed to the king of Apicarta as part of an alliance between the countries. Though she was purportedly descended from Peredur, she had no magical abilities and none of her descendants have manifested such powers.
She lived to see the deaths of her two youngest, most likely at the hands of her eldest. She is often called "the mourning queen" or "the banshee queen" and is a popular figure in legend, appearing as a wailing, weeping ghost lamenting the deaths of her offspring.