I randomly found this on Reddit
"Book 3: Mavra is in a position to destroy one of the holy swords, but doesn't.
Book 6: Ebenezar is tasked with keeping Mavra's magic shut down. She uses a veil to take pictures of Murphy without Harry noticing, and then makes an illusion of herself getting killed. Eb doesn't mention failing at his task. Possible explanation: Eb and Mavra are allies?
Book 7: Mavra hires Harry to get the Word of Kemmler. Gets it. Has 8 books to use it and become an evil demigoddess, doesn't.
Book 12: 12 members of the Grey Council show up for Harry. We know Odin and Eb. Word of Jim is 6 others who showed up are characters we've met."
Fast forward to BG... Mavra could have killed Harry, and didn't. She tells the others that he's being saved for Drakul, but the others didn't seem to care about that at all.... Either Mavra is more loyal to Drakul than the other vamps or..... she was saving Harry...