Your soul is spiteful against those that would seek to cause you suffering or send you into the afterlife. You know how to make those that would end your life suffer one last stroke of vengeance in the hopes that they would perish for their transgression.
Benefit: You may prepare any spell as your vengeful death spell. Once prepared, the vengeful death spell is “held in reserve” and you cannot regain or refill that spell slot. Spontaneous spell casters may still designate a spell to be a Vengeful Death spell, essentially losing a spell of that level. The Vengeful Death spell is tied to your life force (or intellect in the case of undead casters). If you are ever taken to -10 hit points or below (or 0 hit points in the case of undead), the Vengeful Death spell immediately triggers. It is centered or targeted upon the creature that struck the killing blow. The target is entitled to the normal saving throw for the spell (if any) but suffers a -2 penalty on the save as the spell is augmented by the energy of your death.
Undefeatable: The Collected Feats Sourcebook, Copyright 2009 – 2010, Louis Porter Jr. Design, Inc. Undefeated, Copyright 2011, Louis Porter Jr. Design, Inc.