The feat Death Devotion says
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). (Complete Campaign 57)
Unlike, for example, the feat Fell Drain (Libris Mortis 27), the negative levels bestowed unto a foe by the melee weapon affected by the feat Death Devotion appear to remain, possibly causing permanent level loss, much like the effect of special ability energy drain. Does a creature possessing the feat Death Devotion (or the foe suffering from negative levels because of the feat) gain the other effects of what is, virtually, energy drain?
- Does a foe that has all of its levels replaced by negative levels bestowed by the effects of the feat Death Devotion rise (immediately? the next night?) as a wight?
- If the foe fails the saving throw, does the creature that's activated the feat Death Devotion bestow unto his foe up to his weapon's critical multiplier in negative levels (if the creature possessing the feat is of sufficient level) if the attack is a critical hit?
- Does the creature that bestowed the negative level gain 5 temporary hit points (10 on a critical hit) for each negative level bestowed? (This last I'm pretty sure is a No because domain feats' benefits are specifically spell-like abilities.)
"Who cares? Nobody's taking the feat Death Devotion anyway"
A human Clr1 with Cha 16, the feat Death Devotion, and the feat Extra Turning (PH 94) can potentially create several packs of wights each day. Such a cleric couldn't do anything with them, though, instead having to convince the wights (Int 11, Cha 15, Diplomacy +2) that he should be allowed to live. (On second thought, maybe only a few gangs of wights per day would be better, skipping the feat Extra Turning and taking instead the feat Undead Empathy (ECS 61)?) While this is for a potential villain, a protagonist who can command (or, at least, negotiate with and, if not, redirect the wrath of) wights early in his career is also an interesting prospect.
Also, while this question comes close, my specific questions remain unanswered.