How to test HD at low levels?

[Story]

Suppose a Wizard wants to find out people's HD. Assume they're cooperative and will accept touch spells, fail saves, etc. What's the best way to do it at low levels?

For example Polymorph lets you exactly pin down HD. If someone can turn into a Six-Headed Hydra but the spell fails when you try to turn them into a Seven-Headed Hydra, then you know they have exactly 6HD. But Polymorph is a 4th level spell, and I'm not sure how to do it at lower levels. Color Spray tells you whether they're 1-2, 3-4, or 5+HD, but it can't tell you the exact HD.

[Flickerdart]

Oriental Adventures has a use for the Sense Motive skill that allows you to find out someone's BAB, which should help when combined with other methods. You can also use a succession of dudes with known Knowledge modifiers taking 10 to see when someone knows something about the intended target.

[QuickLyRaiNbow]

Hm. Fell Drain + metamagic reduction + tapping them with acid splash until they die?

[Venger]

Oriental Adventures has a use for the Sense Motive skill that allows you to find out someone's BAB, which should help when combined with other methods. You can also use a succession of dudes with known Knowledge modifiers taking 10 to see when someone knows something about the intended target.

was it changed in the 3.5 update? I'm looking at my copy, and it says you can also find out his level, but it only gives "total attack bonus" with his weapon, not just BA, so you'd need to factor out strength and other bonuse.

[Flickerdart]

was it changed in the 3.5 update? I'm looking at my copy, and it says you can also find out his level, but it only gives "total attack bonus" with his weapon, not just BA, so you'd need to factor out strength and other bonuse.
Hm, it's entirely possible that I'm remembering incorrectly.

Anyhow, you can always take his weapon away and then damage him to STR 0 using chill touch or poisons.

[Jack_Simth]

Suppose a Wizard wants to find out people's HD. Assume they're cooperative and will accept touch spells, fail saves, etc. What's the best way to do it at low levels?

For example Polymorph lets you exactly pin down HD. If someone can turn into a Six-Headed Hydra but the spell fails when you try to turn them into a Seven-Headed Hydra, then you know they have exactly 6HD. But Polymorph is a 4th level spell, and I'm not sure how to do it at lower levels. Color Spray tells you whether they're 1-2, 3-4, or 5+HD, but it can't tell you the exact HD.

It doesn't take magic to get in-game numbers (although magic helps). Just lots of logical thinking and statistics.

You can measure strength directly by way of a lifting competition (carrying capacity is based strictly on Strength).
You can sort a large number of people by BAB+Str with a long improvised heavy melee weapon competition (BAB + Strength).
You can measure BAB + Dex by way of an improvised weapon throwing competition (there's dice involved, so statistics are needed here, but it is knowable).
You can measure Con scores by way of a series of breath-holding competitions (there's a check involved towards the end, so statistics are needed here, but it is knowable).
You can measure hit points with a forced march at a hustle (fixed rate of nonlethal damage with time).

Strength you can get directly.
The melee competition results, adjusted for strength, yields BAB.
Adjusting for BAB from the throwing competition results gives you Dex.
Constitution you can get directly.
With BAB, hit points, and Constitution... well, you can use those to solve for hit dice, which is what you wanted. So I've got some extraneous steps in there, but meh.

[QuickLyRaiNbow]

It doesn't take magic to get in-game numbers (although magic helps). Just lots of logical thinking and statistics.

You can measure strength directly by way of a lifting competition (carrying capacity is based strictly on Strength).
You can sort a large number of people by BAB+Str with a long improvised heavy melee weapon competition (BAB + Strength).
You can measure BAB + Dex by way of an improvised weapon throwing competition (there's dice involved, so statistics are needed here, but it is knowable).
You can measure Con scores by way of a series of breath-holding competitions (there's a check involved towards the end, so statistics are needed here, but it is knowable).
You can measure hit points with a forced march at a hustle (fixed rate of nonlethal damage with time).

Strength you can get directly.
The melee competition results, adjusted for strength, yields BAB.
Adjusting for BAB from the throwing competition results gives you Dex.
Constitution you can get directly.
With BAB, hit points, and Constitution... well, you can use those to solve for hit dice, which is what you wanted. So I've got some extraneous steps in there, but meh.

Can you solve for hit dice? I don't know, but...


https://www.youtube.com/watch?v=gENVB6tjq_M

[A_S]

With BAB, hit points, and Constitution... well, you can use those to solve for hit dice, which is what you wanted.
I don't think you can, really.
HP/hit die varies randomly. Many DM's use max or average hit points, but this is a house rule.
Even if such a house rule is in place, you'd need to know the size(s) of their hit dice, which you can't derive directly from BAB (many classes have the same BAB but different-sized hit dice). Characters may have in-universe knowledge about their classes, but that's hardly a given. A Cleric might know that he's only ever trained as a doctrinaire member of the Church Militant, but a Fighter/Rogue who the DM is using to represent a soldier who's learned a little about how to fight dirty might not know that he's a Fighter/Rogue. Depends on how mutable class fluff is being treated in a given game.
Even if you can determine a character's class split, your calculations will still be messed up by anything else that has an effect on HP independent of hit dice (e.g., the Toughness feat).
-----

A Cleric with Imbued Healing and the Healing domain can cast Cure Light Wounds on a target, which will give them 1 temporary HP per hit die of the target, then hit them with something that always deals 1 damage (say, the unarmed strike of somebody with a really low Str score), and count the number of additional strikes required to knock them out. Still doesn't help our OP's low-level Wizard, though.

[momothefiddler]

Are we allowing other individuals of known HD? Or other individuals at all? I think the answer lies in the spells that affect a certain total number of HD. For instance, take four peasants. Confirm that they're 1HD each by having them bunch up and fail a save vs Sleep, then see how many of them you can have in the same area as your target while still successfully putting your target to sleep. For instance, if your target has 2+ HD, then three peasants will be enough to make them immune to Sleep, and so on.

That gets you up to 4HD with a 1st-level spell. If you're willing to throw a statistically relevant number of Hypnotisms at varying piles of peasants and your target you can get pretty good probabilities up to 8HD but that feels inelegant.

If they're immune to Sleep but not Cause Fear, they're 5HD. That's as far as we can get with 1st-level spells, at least from the PHB.

Immunity to Cause Fear but not Daze Monster means 6HD. 2nd level spell.

If you know your own level (a reasonable assumption, I feel), you can use Hypnotic Pattern statistically, like Hypnotism, but with a slightly higher cap. Meh.

Deep Slumber + 9 peasants measures up to 10HD. 3rd level spell.

Rainbow Pattern gets you up to 24HD. 4th level spell.

...And that seems sufficient for low levels, tbh.

(I wasn't able to confirm that peasants are in fact minimum 1HD. If they are not, or we don't get to assume they are, start with Sleep on a clustered group of as many as possible, then proceed in increments of 1/4 of whoever failed).

[Firest Kathon]

Color Spray tells you whether they're 1-2, 3-4, or 5+HD, but it can't tell you the exact HD.

(I wasn't able to confirm that peasants are in fact minimum 1HD. If they are not, or we don't get to assume they are, start with Sleep on a clustered group of as many as possible, then proceed in increments of 1/4 of whoever failed).

If you combine these methods you can easily confirm the 1HD: If Color Spray confirms 1-2, and four of them can be affected by Sleep, then they are 1HD each (either human with no class, or 1 level of any class).

[momothefiddler]

If you combine these methods you can easily confirm the 1HD: If Color Spray confirms 1-2, and four of them can be affected by Sleep, then they are 1HD each (either human with no class, or 1 level of any class).

No, because Color Spray isn't technically 1-2, it's <=2. I'm just not certain if it's possible for a peasant to be <1, is the issue. I know a rat can because that's in the Sleep example; I'd previously just been assuming 1 was the minimum.

[Uncle Pine]

Suppose a Wizard wants to find out people's HD. Assume they're cooperative and will accept touch spells, fail saves, etc. What's the best way to do it at low levels?

Sense Motive can be used broadly determine the HD/level of an opponent (Rules Compendium 68).
Power Sight is an istantaneous, no save, no SR spell with a range of close that tells you how much HD the target creature has (Masters of the Wild 92, not updated).

A custom item of Power Sight would be pretty cheap and efficient.

[Jack_Simth]

Can you solve for hit dice? I don't know, but...


https://www.youtube.com/watch?v=gENVB6tjq_M
Well, if you really want to be sure, you can measure HP and Con, adjust Con by a known amount (apply Greenblood oil to the target, or add a +2 Con amulet), and re-measure HP.

[Story]

Great idea about using Hustle to measure hp. Of course, it's a bit granular, so you'd need to combine it with some other effects to narrow things down. For example, if you hustle for 6 hours before falling unconscious, that just means you have 16-31 HP.

[Firest Kathon]

No, because Color Spray isn't technically 1-2, it's <=2. I'm just not certain if it's possible for a peasant to be <1, is the issue. I know a rat can because that's in the Sleep example; I'd previously just been assuming 1 was the minimum.

I was about to write that humans have 1HD, making this a safe assumption, but upon trying to check it i found that there is actually no Monster entry (on the SRD) for Humans which would define its classless hit dice. You could use dwarves instead, because they do have an entry (http://www.d20srd.org/srd/monsters/dwarf.htm). It shows them as a Warrior 1, but the following tells us that they have exactly 1 HD (from the description of the Humanoid (http://www.d20srd.org/srd/typesSubtypes.htm#humanoidType) creature type):

Humanoids with 1 Hit Die [...] are presented as 1st-level warriors

Edited to add: Alternatively, make sure they have at least one class level by testing one of the 1st-level abilities (and I just noticed that a formerly classless humanoid loses proficiency with all simple weapons except one if he gains the first level of commoner...).

[Jormengand]

Truespeak ranks and the Lesser utterance of the Evolving Mind feat. Utter at them and see how hard it is.

[Curmudgeon]

You can measure hit points with a forced march at a hustle (fixed rate of nonlethal damage with time).
How do you know if it's a hustle? If their base speed is high enough it could just be a walk for them.

[momothefiddler]

Well, if you really want to be sure, you can measure HP and Con, adjust Con by a known amount (apply Greenblood oil to the target, or add a +2 Con amulet), and re-measure HP.
Ooh, nice one. You don't even need to know the prior Con.


I was about to write that humans have 1HD, making this a safe assumption, but upon trying to check it i found that there is actually no Monster entry (on the SRD) for Humans which would define its classless hit dice. You could use dwarves instead, because they do have an entry (http://www.d20srd.org/srd/monsters/dwarf.htm). It shows them as a Warrior 1, but the following tells us that they have exactly 1 HD (from the description of the Humanoid (http://www.d20srd.org/srd/typesSubtypes.htm#humanoidType) creature type)
Aha! Using dwarves then saves us from the step of putting arbitrarily many peasants into a finite space and (and I missed this part originally) making sure they're all the same HD as each other. I think that works, then - Sleep next to dwarves.


How do you know if it's a hustle? If their base speed is high enough it could just be a walk for them.
Wait, no, that's fine. Jack_Simth's Con modification idea means you can use a single 2nd-level spell (Summon Swarm - bats), wait until the target is disabled, increase their Con by 2, and count the rounds until they're disabled again. However many rounds that is is their HD. You don't even have to know their max HP!

[Andezzar]

Truespeak ranks and the Lesser utterance of the Evolving Mind feat. Utter at them and see how hard it is.I knew Truenamers were good for something.

[Jack_Simth]

How do you know if it's a hustle? If their base speed is high enough it could just be a walk for them.
I'm assuming that you know what race they are, but regardless, having them run flat-out for a particular amount of time gives you a pretty good idea what their base land speed is (run distance is x4 base, or x5 with the Run feat; a base move of 5 gets 20 or 25 feet a round; a base move of 10 gets 40 or 50; a base move of 15 60 or 75; a base move of 20 80 or 100; a base move of 25 100 or 125; and so on - even if you don't know whether or not they have the run feat, there's no ambiguity if they are actually running).


Great idea about using Hustle to measure hp. Of course, it's a bit granular, so you'd need to combine it with some other effects to narrow things down. For example, if you hustle for 6 hours before falling unconscious, that just means you have 16-31 HP.
Ah, but it's nonlethal damage! (http://www.d20srd.org/srd/combat/injuryandDeath.htm#nonlethalDamage) That recovers at a fixed rate based on your HD (1 per level per hour). The hustle tells you exactly how much they took, and you can time how long they take to fully recover (I'm assuming you can tell if they're fatigued or not). Regeneration or fast healing will fuzz your results, as will immunity or resistance to nonlethal or fatigue, but little else will.

Let's see....
2 hours hustling: 1 nonlethal.
3 hours hustling: 1+2=3 nonlethal.
4 hours hustling: 1+2+4=7 nonlethal.
5 hours hustling: 1+2+4+8=15 nonlethal.
6 hours hustling: 1+2+4+8+16=31 nonlethal.
7 hours hustling: 1+2+4+8+16+32=63 nonlethal.
8 hours hustling: 1+2+4+8+16+32+64=127 nonlethal.
9 hours hustling: 1+2+4+8+16+32+64+128=255 nonlethal.

If they hustle for two hours before collapsing, they've either got some severe HP problems (there's a few things that can get your HP down to less than 1 per HD, but they're rare) or they've got 1 HD or less.
If they hustle for 3 hours, and recover fully in 3, then they've got 1 hit die. If it takes 2 hours, then they've got 2 hit dice. If it takes 1 hour, then they've got 3 or more hit dice (and have severe HP problems).
If they hustle for 4 hours, and recover fully in 7, then they've got 1 hit die. If they recover in 4 hours, then they've got 2 hit dice. If they recover in 3 hours, then they have 3 hit dice. If they recover in 2 hours, then they have 4-6 hit dice (and more tests will be needed; put on the amulet of +2 Con and re-test), if they recover in 1 hour, then they have 7+ hit dice (and severe HP problems).
And so on.

[Story]

Wait, no, that's fine. Jack_Simth's Con modification idea means you can use a single 2nd-level spell (Summon Swarm - bats), wait until the target is disabled, increase their Con by 2, and count the rounds until they're disabled again. However many rounds that is is their HD. You don't even have to know their max HP!

I think that's the best idea yet. If you use Bear's Endurance for the Con boost, then it can be done entirely by a standard level 3 Wizard, and it's even core only. Of course, healing them up afterwards so they don't die is more difficult.

[Jack_Simth]

I think that's the best idea yet. If you use Bear's Endurance for the Con boost, then it can be done entirely by a standard level 3 Wizard, and it's even core only. Of course, healing them up afterwards so they don't die is more difficult.Cross-class UMD and a few wands of Cure Light Wounds?

[momothefiddler]

If you use Bear's Endurance for the Con boost, then it can be done entirely by a standard level 3 Wizard, and it's even core only.

Beautiful!

[StreamOfTheSky]

The use of Sense Motive that people are talking about is the one described in C.Adventurer, I think. Though I thought that was in terms of CR relative to you, not HD. It's not reliably accurate on its own, but with the Combat Intuition feat it becomes pretty good.