Question: Nystul's Magic Aura-Mask?

[Arial Black]

Nystul's Magic Aura can be cast in either of two ways:-

1.) False Aura: You change the way a creature or object appears to effects that detect magical auras, such as with the spell detect magic (Obviously).

2.) You change the way a creature appears to effects that detect creature types*, such as a paladin's Divine Sense or the trigger of a symbol spell. You choose a creature type and other spells and magical effects treat the target as if it were a creature of that type or of that alignment.

* like, dragon, giant, beast, humanoid, etc.

For example, a magic mouth may be set to speak its message when the enspelled object is handled by a humanoid. If a humanoid (human, elf, drow, dwarf, whatever) handles the magic mouthed item, the spell triggers and the pre-set message is spoken, but if a (say) giant handled the item then magic mouth would not be triggered.

So far, so good.

So I, a high-elf bladesinger, am a humanoid. I cast Nystul's magic aura on myself, the 'mask' version, so that "spells and other magical effects treat (me) as if (I) were a...." celestial. Or dragon. Or whatever I chose when I cast the spell.

Cool.

Later, a baddy casts hold person on me. This spell says, "Choose a humanoid you can see within range".

But spells treat me as if I were a celestial. Don't they?

So the question is: am I affected by hold person while I'm 'masked' as a (not humanoid) by Nystul's magic aura, RAW.

And, by extension, do ALL spells which only target certain creature types treat me as if I were my mask. NMA seems to indicate so.

So which is it? Why or why not, according to RAW?

 

[jgsugden]

While there is some room to debate - No. This masking does not protect you from Dominate person or Hold person.

The spell changes the way that the target appears to spells and magical effects that detect creature types. However, these spells do not detect creature types directly. They just fail to work unless the creature is of the appropriate type.

Look at hold person. You, not the spell, target a humanoid. The spell does not detect whether the target is a humanoid.... it just fails to work if the target is not a humanoid.

This is similar to throwing a towel on a pool or water and another towel on a pool of sand. The towels are not determining if the sand and water are liquid... they just fail to or succeed in absorbing materials based upon the characteristics of the material they touch.

To me, the spell would need to explicitly make a determination of the creature type in order for it to be fooled.

 

[Mort]

But spells treat me as if I were a celestial. Don't they?

It could certainly be worded better, but, no, I don't think so. The relevant part of the spell:

Mask: You change the way the target appears to spells and magical effects that detect creature types. You choose a creature type and other spells and magical effects treat the target as if it were a creature of that type or of that alignment.

The bolded part pretty clearly says that the spell only applies to spells that detect creature types, so the second sentence only applies for that purpose.

Keep in mind that if your rule in the other direction, then additional shenanigans can ensue. Namely, why waste a 5th leve Hold monster slot on a non-humanoid (or, more likely, you don't have 5th level slots)? Just cast Nystul's magic aura on them (it doesn't even say they get a save per RAW, and the word willing does not seem to appear!) and then cast a hold person.

 

[Gwarok]

This is an awesome question. There is no purely correct answer RAW, and I think assuming that the phrase "Detects creature types" can be read a few ways. Does sunlight "Detect" a vampire and upon doing so unleash it's effects upon them? Does a Forbiddance spell do so? Can it be tricked? Is the effect something held back by a trigger to only work on certain targets but unrestrained would affect all? Does that phrase imply some sort of divination component to the spell, is that what they meant by detect?

Keep in mind this is an illusion spell not a transmutation, I think that helps.