Template Help: Evolved Undead template, does fast healing stack?

[Belzbet]

I have been looking over templates in Libris Mortis and I came acrossed the evolved undead template... The thing is that the template leaves it open for us to apply it to undead multiple times... In general I would say fast healing from two different templates DOES NOT stack (although I could be wrong about this); but since they designed this template with the thought of applying it mutiple times do you think they intended for the fast healing 3 to stack with each application of the template (i know this could get crazy though like fast healing 30 with 10 applications of the template to an undead so maybe I have my answer but what do you think) ?

Also do you guys think that I would need to raise the CR adjustment if I added to the template an increase in HD by one (so for each application of the template the undead would get a d12 and the corresponding increases such as BA and save increases; if I added the increase in HD i think I would have to say that the fast healing only raises by 1 for each extra application after the first if it is raised at all)?

By the why sorry for all the undead questions I am planning a big excursion into the negative energy plane where a castle located on a doldrum (a place that is minor negative dominant or having no adverse planar traits at all in some points) harbors a group of Nerull worshipers that are causing all kinds of destruction on a town where they have succeeded in creating a portal too... So I am creating all kinds of undead NPC and some questions have came up...

 

[Ahnehnois]

The answer appears to be yes, the fast healing stacks.

The closest thing I could find to an official answer at forst glance was this article that mentions an undead with the template and scales the fast healing up with everything else ("fast healing 18").

If you applied the template a large number of times, the fast healing would get ridiculous, but many aspects of the creature wouldn't be improved, potentially creating an unkillable monster with weak saves that can't hit anything. I would suggest using discretion with this template.

Also do you guys think that I would need to raise the CR adjustment if I added to the template an increase in HD by one (so for each application of the template the undead would get a d12 and the corresponding increases such as BA and save increases; if I added the increase in HD i think I would have to say that the fast healing only raises by 1 for each extra application after the first if it is raised at all)?

...
Generally, templates don't add HD like that. Since most undead have existing advancement by hit dice (or are unintelligent) I don't see any reason to do this. Just advance the undead to the HD level you like (under the existing CR rules), then add the template.
If you just want an excuse to replace the fast healing, I'd replace it with something else.

 

[Empirate]

In my opinion, fast healing of any numerical value is vastly overrated. It's extremely useful to PCs, in that they consume much less resources for healing if the fast heal. But monsters will most likely just get a round or two extra out of fast healing. Even at fast healing 30 (applying the template 10 times, so increasing CR by a very large amount) is only 30 HP/round. At the level of play you can introduce such a monster, your party warrior(s) will most likely be striking for that much and more per attack instead of per round.

Don't be afraid of fast healing monsters. They will instill a certain degree of terror in your PCs (which is as it should be), and they will reinforce the already sound tactics of "kill one thing completely before engaging a second". That's all.

 

[Ahnehnois]

In my opinion, fast healing of any numerical value is vastly overrated.

I kind of agree, but the other issue here is the tactical options fast healing grants. As long as you can survive a round or two of combat, you can dish out some damage, take a few hits, and then run. This tactic is especially effective if you can dive into the ground, and undead are often incorporeal. It allows you to fight a very effective war of attrition.

That said, FH is not a game-changer most of the time. +3 to AC or attacks changes a monster's difficulty more than 3 fast healing.

 

[Empirate]

Agreed, incorporeal fast healers are the stuff of nightmares. Especially if your party doesn't have the combat power or special abilities to set up either a one-shot kill, or a successful disabling of its powers. Evolved Undead Dread Wraiths are just no fun at all. The only thing you can do is get a fly speed greater than they have, and get far away from all solid surfaces...

But even then, it's not how many points of fast healing the creature possesses, but whether it has any fast healing at all.