Vampirism

Vampirism presumably determines whether the called actor is a vampire or not. 0 would be the default value, while 1 or greater would mean that the actor is a vampire.

Vampirism is the actor value that determines how far you've progressed as a vampire. A value of 0 means that you're not a vampire. The Default is 0. The vampire abilities modify this stat to be 25 (just fed), 50 (1 day without feeding), 75 (2 days without feeding), and 100 (3 or more days without feeding). This stat, in conjunction with the PCVampire global variable, lets the VampireScript keep track of your vampire's abilities.