Importance of High Priestess Viviane

High Priestess Viviane was the original leader of the Nine who passed away before the opening of the novel. While she was the lover of Morgan Le Fay, Viviane was supposedly heartbroken when the Sorceresses chose to fight the druids, even leaving Morgan’s body in a coffin rather than burying her which would allow her soul to be reborn. However, it is later revealed that Viviane was proficient in some level of death magic and became a revenant after her death. Caitriona and Tamsin kill this version of Viviane, freeing her once again. However, it is later revealed that Viviane knew Lord Death wanted to trick the Priestesses into casting the spell to set him free and that the revenant was born from that desire.