2 levels, 1 point per level
The character loses twice as many HP as normal from a particular attack form. It might be something with appropriate mystic resonance, such as wooden stakes for vampires or silver for werewolves. It could also reflect the character's nature, such as a fire elemental taking extra damage from water, or a faerie's vulnerability to cold iron. The GM must approve any vulnerabilities to prevent abuse of the system. A character may be vulnerable to either a common or rare attack form. Examples of common attack forms are fire, metal weapons, wooden weapons, and special attacks. Examples of rare attack forms include a particular kind of attack (such as lightning or wind), silver weapons, and a weapon blessed by a religious leader. For every GM-approved vulnerability after the first one, add 1 point.
Level One: The attack form is rare.
Level Two: The attack form is common.