Anastasia is a 550 years old vampire and the mistress of the Bloodcurse Mansion. She is a vampire who is kind in the heart, but also serious when she is after someone's blood in a hunt. Her reputation from the residents of the mansion is to be a good and fair mistress with a lot of dark powers who knows how to use it. Her best friend is also her personal composer Musica and calls her sometimes even as Musi. She loves to listen to the music from Musica. Beloved by the maids and head maid, even if all the maids are humans. And also watching to her gatekeeper Cecilia Joker and her librarian, scientist and astronomer and astrologer Roberta Helios. Anastasia's ability is to see someone's future as long the person in front of her knows the right information. Rumors are telling that the Bloodcurse family clan are best friends and loyal allies of the Scarlet family clan. She also knew Remilia as little child and Flandre as baby.
The mistress of the Bloodcurse mansion who is quite often busy in her own room, but also strengthen the bound with the other residents of the mansion, especially with Musi her best friend. The Bloodcurse Mansion is in a kind of second Gensokyo that was once a part of the other Gensokyo.