Ysandre was a stunningly beautiful and extremely promiscuous vampire who came to Morganville with Bishop. She had the ability to manipulate the thoughts of both humans and vampires, particularly those of men, and force them to do and feel what she wanted. She was very interested in Shane, in that she wanted him as her pet, and sent him an invitation demanding that he accompany her to Bishop's welcome feast, at which she forced him to wear nothing but leather pants, a dog collar and a leash that she held.
Ysandre wanted to be Oliver's second-in-command when he briefly took control of Morganville from Amelie, but Oliver made it clear to her that he wanted Amelie as his second-in-command. This angered her so much that she tried to kill Amelie, saying that she just needed to get rid of the competition for him to notice her worth. She failed, however, and Oliver ordered her to be executed, judging her to be too dangerous to be kept alive.