Vampirism
This actor value controls the vampire 'morphing' of a character's face, in a scale of 1 to 100. Higher values translate into a more gaunt face with hollower cheeks and more prominent eyebrows. It also triggers other hardcoded features pertaining vampires, namely the GetVampire function will return 1 for any character with any amount of Vampirism, and the player will receive the popup messagebox when activating sleeping NPCs offering to trigger the blood drinking animation and sounds (which in turn set the HasVampireFed function to 1)
It is used by the VAMP magic effect, and should be applied through abilities with it, like in the vanilla VampireScript. Note that the vanilla implementation uses it in steps of 25 points, but any magnitude is possible and each increment of 1 point is applied to the morphing, albeit the difference between values of (x) and (x+1) is almost unnoticeable.