Gwyn ap Nudd has two identities in The Merlin Conspiracy. One is that of the main character Arianrhod Hyde's grandfather, a Welsh preacher who lives in a dark old rectory house in the Welsh hills, and who seldom sees his granddaughter.
The other is that of a powerful magical individual, whose identity is based in Welsh mythology.
Lord of the UnderworldEdit
As Gwyn ap Nudd the enchanter, he leads the Wild Hunt -- a crowd of ghostly mounted figures who ride through walls and spirit souls away from life. In the book, Gwyn is subjected to the will of the magical leaders of the Islands of Blest, and forced to obey their orders three times before he can regain his freedom to take his own part in the conflict that is pulling the world apart.
Gatekeeper to the Flower WomanEdit
At the same time, Gwyn calls Arianrhod away from her life at court, which involves being one of the schoolchildren among the courtiers who are following the King's Progress as it wanders all over around the Kingdom.
Taken by car to her grandfather Gwyn's rectory, Arianrhod finds that her grandfather is the first adult who actually believes her story about the conspiracy that is undermining the kingdom. He tells her that he has been controlled, and can do nothing directly, but that if she is willing, he can direct her to a place where she will gain power that will enable her to help stand against the threat. She agrees to do so, and follows his instructions to a place where she is inhabited by the knowledge of a long-dead sorceress who has been searching the future for someone similar enough to master the encyclopedic knowledge of magic based on flowers. For the remainder of the novel, Arianrhod struggles to get to a place where she can figure out how to make use of this knowledge to do battle against the conspirators, and save the lives of all the people she most cares about.