Vorpal Immunity
Costs 1 XP/tier
You are not instantly killed by decapitation. If you have multiple heads, all must be decapitated for you to die of decapitation.
If you have only one head, you still hear, see, and speak through your severed head but remain alive after decapitation and can operate your body through a telepathic link. Damage and conditions dealt to either the head or body affects your normal hit point pool shared between them. Your head can be re-attached as a standard action.
Tier 2: You cannot be decapitated by any effect at all to begin with, though you may still have a vestigial head that can be decapitated, doing so does not inconvenience you.