Destruction Retribution

 
Prerequisite(s): Corpsecrafter
 
Benefit: Each undead you raise or create with any necromancy spell releases a burst of negative energy upon its destruction, dealing 1d6 points of damage plus an additional 1d6 points per 2 Hit Dice to every creature within a 10-foot spread (Refl ex DC 15 half). This damage comes from negative energy, and it therefore heals undead creatures.
 
Source: Libris Mortis