So I've just got one quick question... does energy drain function on any natural attack, or is it just slams?
For example... say a vampire took a couple levels of monk and decided to use his fists or his claws. Would each hit cause energy drain?
Points at PRD link to the left...
Energy Drain (Su): A creature hit by a vampire's slam (or other natural weapon) gains two negative levels. This ability only triggers once per round, regardless of the number of attacks a vampire makes.
A monk's unarmed strike is treated as both a manufactured weapon and a natural weapon for the purpose of spells and effects that enhance or improve either manufactured weapons or natural weapons.