Death Devotion

 
Prerequisite(s): Access to the Death Domain
 
Benefit: Once per day as a swift action, you can cause one of your melee weapons to radiate negative energy for 1 minute. When you make a successful attack with this weapon, the target must succeed on a Fortitude save (DC 10 +1/2 your character level + your Cha modifier) or gain a negative level. You can bestow only one negative level per target for every four character levels you possess (minimum one, maximum five negative levels at 20th level).
 
Special: You can select this feat multiple times, gaining one additional daily use each time you take it.|||If you have the ability to turn or rebuke undead, you gain one additional daily use of this feat for each three daily turn or rebuke uses you expend.
 
Source: Complete Champion