Who is Maude Clifford from The Reckoning and what is their importance?

Maude Clifford is Llewelyn Farr's granddaughter. She is the cousin of both Llewelyn ap Gruffydd and Ellen de Montfort. Widowed at a young age, Maude is kidnapped by John Giffard who wants to claim the lands of her dead husband. Cliffors rapes her and forces her into marriage.