Nondetection + (Improved) Invisibility

[Shin Okada]

Would you please check if my rule interpretation is right (or reasonable) or not?

From SRD,

Nondetection
Abjuration
Level: Rgr 4, Sor/Wiz 3, Trickery 3
Components: V, S, M
Casting Time: 1 standard action
Range: Touch
Target: Creature or object touched
Duration: 1 hour/level
Saving Throw: Will negates (harmless, object)
Spell Resistance: Yes (harmless, object)
The warded creature or object becomes difficult to detect by divination spells such as clairaudience/clairvoyance, locate object, and detect spells. Nondetection also prevents location by such magic items as crystal balls. If a divination is attempted against the warded creature or item, the caster of the divination must succeed on a caster level check (1d20 + caster level) against a DC of 11 + the caster level of the spellcaster who cast nondetection. If you cast nondetection on yourself or on an item currently in your possession, the DC is 15 + your caster level.
If cast on a creature, nondetection wards the creature’s gear as well as the creature itself.
Material Component: A pinch of diamond dust worth 50 gp.

So, if someone casts both Nondetection and (Improved) Invisibility on him,

1. It will protect him against See Invisibility and True Seeing

As those two are divination spells to detect invisible/hidden creatures and things.

2. It will not protect him against Detect Magic/Arcane Sight/Greater Arcane Sight

While those are divination spells, those spells let the caster detect the magical auras of Nondetection and XX Invisibly spells, not the protected creature itself.

3. It will not protect him against Invisibility Purge

Because Invisibility Purge is an Evocation spell, not a Divination spell.

 

[NewJeffCT]

Would you please check if my rule interpretation is right (or reasonable) or not?

From SRD,



So, if someone casts both Nondetection and (Improved) Invisibility on him,

1. It will protect him against See Invisibility and True Seeing

As those two are divination spells to detect invisible/hidden creatures and things.

2. It will not protect him against Detect Magic/Arcane Sight/Greater Arcane Sight

While those are divination spells, those spells let the caster detect the magical auras of Nondetection and XX Invisibly spells, not the protected creature itself.

3. It will not protect him against Invisibility Purge

Because Invisibility Purge is an Evocation spell, not a Divination spell.

I think you're correct on #1 and #3. Not sure on #2, but I think they'd still have to make the caster level check to be able to detect nondetection.

 

[cheshire_grin]

I would rule that the "and detect spells" implies protection from Detect Magic/Arcane Sight/GAS, although the "if a divination is attempted against the warded creature or item" makes that less than crystal-clear.

I don't see any difference between #1 and #2 -- both are spells targeted on the caster, not spells targeted on the warded creature, so either both sets will work or both sets will be denied by the nondetection.

#3 is definitely correct; it won't protect against non-divinations.

 

[green slime]

I agree with you completely. Your point #2 will of course not detect the creature per se, but instead reveal the existance of something magical within the area.

 

[AuraSeer]

I think the rules are unclear, and I happen to have ruled the other way. IMC, nondetection does not stop see invisibility or true seeing. It seems to me that those effects are not designed to "detect" the creature per se. They merely let the caster see through the magical invisibility effect.

To put it another way, I rule that nondetection does not prevent the target from being sensed by ordinary sense organs, even if they are enhanced by magic. Spells like see invis grant the caster's eyes the ability to see through the covering illusion, but do not grant him a whole new sense that he otherwise lacked; his eyes can physically see the warded creature.

I could have gone either way with this ruling, but I decided this way because the combination of spells would seem too powerful otherwise. I consider invisibility balanced only because there are lots of ways to see through it. Giving impenetrable invisibility to a 5th-level character seems too strong to me.

(This came up again recently when somebody used the psionic darkvision power, which counts as divination. I had to figure out whether nondetection prevented him from seeing a creature 10' away in the darkness who would have been perfectly visible by torchlight. Weirdly, this isn't a concern with the darkvision spell, because that's a transmutation.)

 

[NewJeffCT]

I think the rules are unclear, and I happen to have ruled the other way. IMC, nondetection does not stop see invisibility or true seeing. It seems to me that those effects are not designed to "detect" the creature per se. They merely let the caster see through the magical invisibility effect.

To put it another way, I rule that nondetection does not prevent the target from being sensed by ordinary sense organs, even if they are enhanced by magic. Spells like see invis grant the caster's eyes the ability to see through the covering illusion, but do not grant him a whole new sense that he otherwise lacked; his eyes can physically see the warded creature.

I could have gone either way with this ruling, but I decided this way because the combination of spells would seem too powerful otherwise. I consider invisibility balanced only because there are lots of ways to see through it. Giving impenetrable invisibility to a 5th-level character seems too strong to me.

(This came up again recently when somebody used the psionic darkvision power, which counts as divination. I had to figure out whether nondetection prevented him from seeing a creature 10' away in the darkness who would have been perfectly visible by torchlight. Weirdly, this isn't a concern with the darkvision spell, because that's a transmutation.)

but, then you have True Seeing and its ability to beat any illusion - even level 9 ones. I think being able to cast 2 spells (Greater Invisibility, level 4, and Nondetection, level 3) to beat True Seeing is ok.

 

[AuraSeer]

Yes, true seeing beats all illusions, but that's a very specialized defense. I don't know of any way to use true seeing to hurt somebody, and it doesn't protect you against anything but illusion effects.

I consider invisibility different because it's a very strong non-specialized defense that works against almost everything. Since the target's square is concealed, it turns most attacks into guesswork. Those few attacks that aim at the right square suffer 50% miss chance. The normal way to bypass a miss chance, using targeted spells, is completely prevented.

If detect spells don't work, the only way to reliably attack the invisible target would be with area effects. That again has the problem of guessing the right spot to aim at. And area effects tend not to have much impact in this situation anyway, because the common users of invisibility are rogues with high Reflex saves and evasion.

On top of that, invisibility also has offensive effects. It grants at least a +2 to hit, and gives rogues a huge damage bonus. It is great for prepping strong abilities, like the assassin's death attack, which are supposed to be balanced by a long setup time.

Again, I think invis is fine as it exists, because there are so many ways to see through it. But if you remove those counters, I think it would become too strong. YMMV.

 

[NewJeffCT]

Yes, true seeing beats all illusions, but that's a very specialized defense. I don't know of any way to use true seeing to hurt somebody, and it doesn't protect you against anything but illusion effects.

True Seeing also beats both magical & regular darkness as well, functioning as a superior version of the spell Darkvision, as it has a range of 120 instead of 60 (in addition to foiling illusions). Darkness and Deeper Darkness, the spells, are evocations.

 

[ElectricDragon]

I look at it like this:

The spell says that a creature's items are also covered by the non-detection effect. I would extend that to the spell emanations also, so that detecting the spell effect would also be covered by the spell's effect thus preventing detection. Thus detect magic would have to make the caster level check, as would any spell labeled "detect" per the spell description. Arcane sight and greater arcane sight are just higher level improvements on the detect magic spell and would also need a CL check.

But, see invisibility and true seeing do not detect the creature, they affect the caster; improving his visual capabilities instead. I don't see that non-detection protects against non-detect spells that only change the caster's senses.

At least that would be my call.

Ciao,
Dave

 

[FEADIN]

Protects against all divinations and detect spells, detect magic is a detect spell and it would be absurd to let the non detection spell be detected.....the only point ruled differently by our DM's was the True seeing spell because it is not listed in the spell description but "all divination spells such as..."
We palyed this way for more than 20 years but you can always think otherwise.