Carmilla is a vampire and teacher of Dead Magic, a subject dedicated to education about forms of magic no longer widely practiced, mostly because those who did practice are dead. Carmilla is played by MewMewMudkip.
Anna's father was the leader of a tribe of Finfolk that were very good friends with a large group of Druids. However, in order to prevent both tribes from being killed, her father practically sold her to the king as a bride for the crown prince. This was okay for a while until Anna gave birth to a child and could not bear the thought of her being raised by humans. So she ran back home and was rejected by her tribe and the Druids refused to help her. Before her husband could find her, she hid in a church and told the priest about the village. She lived in the ocean as a selkie with only a small family of seals and her daughter as company. One spring, there was a mass of sealers larger than there had been before and she decided to take her daughter back to her father.
Once she met her husband, they fought constantly and because their daughter seemed so happy, she left her in his care to be raised as a princess.
Since then she has roamed the world learning all she can about all kinds of magic, including cultures she helped destroy so she could wield their power. Not long before she came to Spirit High to teach "Dead Magic" she became a vampire via conventional methods, and then killed the one who changed her and changed her name to Carmilla.