Actually it fits with a theory I've had and wrote and debated about some time ago. That Justine was infested or possessed by Nemesis at least as far back as White Night, but very possibly before.. Not saying she and Thomas didn't love one another, I have to do some rereading of Grave Peril, but I seem to remember that Lord Raith set her up as food for Thomas, and it just so happened that with her he was able to control himself and not kill her, and the feeding seemed to control her insanity? Or in Blood Rights when he was dying, he fed upon her to the point of her death and then stopped, and both survived? All a beautiful love story, but maybe a little too perfect.. Maybe she was possessed by Nemesis all along and this was a why she survived the feedings, maybe she was actually controlling Thomas from the first. Then in Peace Talks after she successfully manipulated him into murder for her sake triggering a war, she discarded him.