Another mini-template, or do we think this is distinct enough for a separate monster? The peculiarity of it as well as the HD suggest separate monster to me.
Did Dark Sun ever get defiling rules in 3.X?
Definitely a new monster.
There are 3E defiling rules in both Dragon magazine and on athas.org, both of which have WotC's blessing (at least to some extent).
We might as well settle on the basics of the monster first, though.
Medium Undead, obviously.
Their 4+4 HD suggests 4 Hit Dice plus Unholy Toughness to give it its Cha bonus as a per-HD hp bonus.
Ability-wise, I was thinking a Ghoul or Ghast would make a good foundation.
Ghast - Str 17, Dex 17, Con -, Int 13, Wis 14, Cha 16
Ghoul - Str 13, Dex 15, Com -, Int 13, Wis 14, Cha 12
Keep the physical scores and drop the mental ones, these are mindless so are Int 0. Drop the other two mental abilities by 2 apiece?
That would make it:
Ghastly Defiler - Str 17, Dex 17, Con -, Int -, Wis 12, Cha 14
Ghoulish Defiler - Str 13, Dex 15, Con -, Int -, Wis 12, Cha 10
Averaging the two would work out to something like:
Defiling Skeleton - Str 15, Dex 16, Con -, Int -, Wis 12, Cha 12
I bumped the Charisma up a point so it has 2 odd abilities and 2 even ones. It doesn't make any difference to it bonus-wise.
If we give them a standard Medium Skeleton's +2 natural armour they'd have AC15 with that Dex. I think I'll cut a point off its Dexterity so (a) they're AC isn't a point higher than a direct conversion of the original's AC6 and (b) most of their stats are +2 higher than a standard human Skeleton.
Defiling Skeleton - Str 15, Dex 15, Con -, Int -, Wis 12, Cha 12
Since these are "Undead Soldiers", should they be proficient in armour? Slapping leather armour on top of their current defences would give them AC 16, which I think is reasonable for a creature of their probably CR.
What weapons do you fancy for them - I was thinking of 2-handed weapons like Spears or Morningstars. As "Soldiers" they might be proficient in martial weapons, so we could give them Greatswords, Scythes or Heavy Flails. I don't fancy Falchions, since we've been using that weapon quite a bit recently.
EDIT: Upon reflection, I would like masterwork greatswords for their main weapon.
I'm presuming they'll have two 1d6+2 claw attacks, so a Greatsword at +1 to hit and 2d6+3/19-20 damage will be a near-equivalent. There's little point in them carrying a weaker weapon than their claws, except for ranged attacks.
Hmm... ranged attacks.
Should we give them a missile weapon too?