Lyonesse Trilogy

The Lyonesse Trilogy is a group of three fantasy novels by Jack Vance, set in the European Dark Ages, in the mythical Elder Isles west of France and southwest of Britain, a generation or two before the birth of King Arthur.

King Casmir of Lyonesse arranges the marriage of his daughter Suldrun to Faude Carfilhiot, Duke of Vale Evander.

Faude Carfilhiot, wanting to be a powerful magician but lacking the patience to learn the necessary skills, schemes with his lover Tamurello.

During an unauthorized outing into a forest, Princess Madouc is separated from her bodyguard and discovers her mother, the fairy Twisk, and learns the truth.

Shimrod the wizard, at Murgen's request, investigates mysterious demonic apparitions in Ys, which appear to involve Melancthe.

Desmei's physical form is destroyed, and Tamurello tries to free Joald with the help of Torqual simply to spite Murgen.

Joald manages to partially wrench free, and his presence in the Atlantic causes a massive tsunami that wipes out Ys instantly and the majority of Vale Evander soon thereafter.

The Green Pearl is revealed to be a corrupting magical force and an element of a much larger inter-dimensional war, which Murgen has been trying to keep from reaching Earth.