Demon Knights Vol. 2: The Avalon Trap — Paul Cornell

On the road to Alba Sarum, the Demon Knights learn the tale of Madame Xanadu and Etrigan, and the twisted love they share. But even more twists abound as the Knights arrive to an assassinated Merlin! Now they must travel to fabled land of Avalon in search of a way to revive their legendary wizard. But what they find on the way is a threat more dangerous than they could have expected and a betrayal from one of their own!