What is Maryann?

As season 2 goes on you learn that Maryann is not human or vampire. She is a maenad. A maenad is a creature that requires offerings from other supernatural creatures who serve alcohol. If they’re not properly honored they tend to get angry and cause madness in people or even kill them. She also cannot be killed. She begins to cause kaos in this small town taking over peoples mind and having them do terrible things.