Available as a ritual.

This spell is taught to the minions of a powerful overlord (such as a Dracolich) who is looking to harvest soul/life essence energy in order to aid in some great ritual.

Casting this spell kills the sacrifice and contributes a soul to the creation of a Soul Jar.  After a hundred victims have been harvested the soul jar is sealed and ready for transport.  Incomplete soul jars may be consumed and bonuses are rolled for record keeping purposes but have no actual benefit for the character.  Completion of the spell takes the target to 0 hit points (if total under 10% of their base HP) and they automatically fail 1 death saving throw.  In addition they must make 1D10 x WIS saving throws against the caster's spell DC with each failed save creating a failed death saving throw.  

If the target is over 10% of their base hit points the spell does only 2D10 HP worth of damage (accordingly in preparation for the ritual targets tend to be beaten to near death to make them vulnerable to the experience).

A complete Soul Jar requires 100 points of life essence/souls.  To be eligible the sacrifice must be sentient (INT of 6 or higher).  Some creatures souls are worth more than others with a base value calculated at 4 x the CR.  The exception is true innocents (such as an infant or Good Cleric) whose souls are worth a minimum of 20 points in contributing towards the completion of a Soul Jar.

Creatures sacrificed in this way are not able to be resurrected by any normal means.  Only the destruction of the Soul Jar's master will free any souls harvested in their name.