When do HD matter for Controlling with Rebuke?

[Brennan1612]

If I am trying to control an undead with 10 HD

I have a rod of Defiance, reducing the effective level of it by 4 (Effective 6 HD while still having 10)

Then I give it 6 Holy arrows, giving it 6 negative levels (effective 0 HD while still having 4)

If I rebuke it to control it, how many HD would it use of my controllable limit, and when is it calculated?

[JediJuliet]

If I am trying to control an undead with 10 HD

I have a rod of Defiance, reducing the effective level of it by 4 (Effective 6 HD while still having 10)

As far as I'm aware this is just the effective level for the purpose of turning/rebuking/bolstering, it doesn't have any impact on other mechanics of their HD (including control limit), so it would still be 10 HD for commanding.

Then I give it 6 Holy arrows, giving it 6 negative levels (effective 0 HD while still having 4)

If I rebuke it to control it, how many HD would it use of my controllable limit, and when is it calculated?

Assuming this counted as wielding ("in hand" for d20 makes me wonder) it'd be a full negative level and then count as having 4 HD (since I don't think Rod of Defiance counts here, genuinely lowering something to 0 HD is supposed to kill it).

[Silva Stormrage]

I am pretty sure Undead are immune to negative levels and wouldn't be affected by the negative levels from Holy Weapons.

Regardless I would say that the temporary HD reduction from Rods of Defiance would help you rebuke and command an undead but wouldn't reduce the HD for the amount of undead commanded.

Thus a level 8 HD undead with rod of defiance would be able to be commanded by a level 10 cleric (It would be treated as a 4 HD undead) but it would still take up 8 HD in their command HD pool.

[Brennan1612]

I am pretty sure Undead are immune to negative levels and wouldn't be affected by the negative levels from Holy Weapons.

Undead are immune to energy drain, not specifically negative levels, though negative levels are generally from energy drain, holy arrows are one exception to that

[Silva Stormrage]

Undead are immune to energy drain, not specifically negative levels, though negative levels are generally from energy drain, holy arrows are one exception to that

That is a stretch, the link to Energy Drain on the undead type literally links to the description of negative levels and the holy weapon negative level links to the same description on the SRD. It might be technically true RAW (I would disagree but I can at least see the argument) but RAI that seems massively unintended.

It doesn't matter too much as I mentioned above Spark of Life would allow it to work even if you side on my interpretation that energy drain immunity = negative level immunity.

[Saintheart]

That is a stretch, the link to Energy Drain on the undead type literally links to the description of negative levels and the holy weapon negative level links to the same description on the SRD. It might be technically true RAW (I would disagree but I can at least see the argument) but RAI that seems massively unintended.

It doesn't matter too much as I mentioned above Spark of Life would allow it to work even if you side on my interpretation that energy drain immunity = negative level immunity.

There's actually four issues here:
(1) Nothing says whether undead are immune to negative levels;
(2) Nothing says whether undead can have negative levels bestowed on them even if they're unaffected by them;
(3) Nothing says uniformly that undead are healed by negative energy effects; and
(4) Nothing says negative levels are a negative energy effect.

The problem is that the original writers wanted mages to bestow negative levels (via Enervation) as well as have monsters that could suck levels off people (thus the Energy Drain (Su) ability, which bestows negative levels and heals the monster at about 5 hitpoints per negative level bestowed). I think they created the concept of negative levels to do that: a freestanding debuff that doesn't depend on Energy Drain (Su) for its interpretation or existence.

Second problem was that they didn't declare negative levels explicitly to be a negative energy effect. There's corroborating evidence that this was the RAI: the Negative Energy Plane bestows negative levels on unprotected visitors, at about once per round, and nerfs the snot out of the Fort saves required to remove them; Enervation (which imposes negative levels and is a Necromancy spell, and speaks of a ray of crackling negative energy in its description) gives temporary hitppoints to undead targets.

My guess for why they didn't make it explicit was because negative energy originally was a damage type, while negative levels are a penalty to hitpoints, saves, skill checks, and attack rolls. It would've confused the two concepts.

Like I said, it doesn't help that while the Undead type says the undead can be healed by negative energy effects, it doesn't say this happens in all cases. Instead, most (but not all) of the time, when something in a spell or class ability hits an undead target with a negative level, it calls out specifically that the undead is healed by it or gets temporary hitpoints. The problem is that it doesn't do so uniformly.

No one combination of answers to these questions produces an entirely satisfactory result. If undead are immune to imposition of negative levels, then a Necropolitan Paladin with a Sacrificial Smiting weapon either has infinite smites per day (if they can be bestowed on him) or no use at all (if they simply can't be bestowed at all.) But conversely it also wouldn't be terribly consistent with the seeming intent of a Holy weapon that an evil undead creature takes no ill effects for carrying it while a living evil creature does.

[Jack_Simth]

That is a stretch, the link to Energy Drain on the undead type literally links to the description of negative levels and the holy weapon negative level links to the same description on the SRD. It might be technically true RAW (I would disagree but I can at least see the argument) but RAI that seems massively unintended.

It doesn't matter too much as I mentioned above Spark of Life would allow it to work even if you side on my interpretation that energy drain immunity = negative level immunity.

Warning: Links in the SRD are not original content from WotC (the original format used for distribution didn't support such). They were added by whoever reformatted the SRD for the site you're using.

[Darg]

If I am trying to control an undead with 10 HD

I have a rod of Defiance, reducing the effective level of it by 4 (Effective 6 HD while still having 10)

Then I give it 6 Holy arrows, giving it 6 negative levels (effective 0 HD while still having 4)

If I rebuke it to control it, how many HD would it use of my controllable limit, and when is it calculated?

Depends on your DM and how they interpret the rules. Commanding undead says, "At any one time, the cleric may command any number of undead whose total Hit Dice do not exceed his level." Common English means that at anytime you control more than HD undead you lose control. However, there is a RAW argument that turn undead is a magical effect that only calculates on activation. As you've figured out, this argument is usually made to create overpowered armies of undead at minimal cost at lower levels than any RAI would ever say is valid. Personally, the less crazy exploitable option is better for the game.

Though, I must warn either way that even an undead creature with effective 0 HD is slain.

[redking]

If I am trying to control an undead with 10 HD

I have a rod of Defiance, reducing the effective level of it by 4 (Effective 6 HD while still having 10)

Then I give it 6 Holy arrows, giving it 6 negative levels (effective 0 HD while still having 4)

If I rebuke it to control it, how many HD would it use of my controllable limit, and when is it calculated?

It only counts for your turning roll and turning damage. The SRD has it as follows:

Turning Check
su The first thing you do is roll a turning check to see how powerful an undead creature you can turn. This is a Charisma check (1d20 + your Charisma modifier). A cleric with 5 or more ranks in Knowledge (religion) gets a +2 bonus on turning checks against undead. Table: Turning Undead gives you the Hit Dice of the most powerful undead you can affect, relative to your level. On a given turning attempt, you can turn no undead creature whose Hit Dice exceed the result on this table.

Turning Damage
If your roll on Table: Turning Undead is high enough to let you turn at least some of the undead within 60 feet, roll 2d6 + your cleric level + your Charisma modifier for turning damage. That’s how many total Hit Dice of undead you can turn.

If your Charisma score is average or low, it’s possible to roll fewer Hit Dice of undead turned than indicated on Table: Turning Undead.

You may skip over already turned undead that are still within range, so that you do not waste your turning capacity on them

.

I am going to set aside the issue of the holy arrows for now because the principle will be the same regardless.

You roll for the maximum HD you can affect and then the maximum turning damage. In these calculations, add anything, like items, that increase your effective cleric level and anything that debuffs the undead creature. So your maximum HD affected and turning damage will all be affected by these modifiers.

At this point, depending on whether you are turning or rebuking, any turned creatures are routed (turned) or awed (rebuked). Now we must consider whether they are also destroyed or command (which will override turning and rebuking effects).

Now you just look at your total character level and the actual HD of the creature (do not calculate turn resistance as we have already passed this turning check phase). If the undead creature is half your total character level or less, it is destroyed or commanded. Let's call this phase 3.

I believe this is all there is to it, but there is some controversy.

Some claim that the Phylactery of Undead Turning and similar items should count as actual cleric levels in phase 3. If it does, the game quickly breaks at this point. I think the designers themselves were confused about what these items are supposed to do. Then there is the Improved Turning feat, which provides for "turn or rebuke creatures as if you were one level higher than you are in the class that grants you the ability". If this didn't count as an actual cleric level for destroying or commanding, it would be a sad feat indeed.