Kinley MacGregor: Sword Of Darkness [2008] paperback

Welcome to the dark side of Camelot …

King Arthur is dead and his arch enemy, Morgen le Fey, has placed the ruthless Kerrigan on the throne of Camelot. Kerrigan, a Lord of Darkness, is feared throughout the land, and will stop at nothing to claim the powerful Round Table of legend. From the refuge of Avalon, the remaining Knights of the Round Table have only one hope for the future. Seren, a young apprentice weaver, dreams of breaking free from her life of drudgery, and becoming her own woman. But destiny has chosen Seren for a higher purpose…