@JeremyECrawford Does Nondetection plus Invisibility beat True Seeing?
— Nathaniel Kreiman (@NKreim) October 13, 2016
The nondetection spell hides you from divination magic. True seeing is a divination spell. #DnD https://t.co/9uxWEh66AE
— Jeremy Crawford (@JeremyECrawford) October 13, 2016
This likely hasty answer is sadly incorrect when time is put towards reading the wording or considering the implications. Greater Invisibility and non-detection would beat many GODS that didn’t have true-seeing inherently or some form of
AoE to wipe the map, as many melee based Gods, not to mention giants and others, do not. This was a well known exploit in 2e and something Mike Mearls fixed in 5e.
True-Seeing does not “target” the invisible creature and therefore by wording does not get stopped by non-detection. True-seeing targets a creature (not the invisible one) that gains an ability which allows them to see invisible creatures. Seeing a creature is not the same as targeting it!
Interestingly, Non-detection does prevent a creature from being buffed by True-seeing.
This is why you don’t listen to Jeremy Crawford. He is all over the place with his rulings. Use his tweets as guidance, but the DM is God at his table.
I tend to agree with Mark’s take on how True Seeing works
Nonderection says targeted division and true seeing does not target
The Amulet states
You are hidden from Divination magic. You can’t be targeted by such magic or perceived through magical Scrying sensors.
The spell states
For the duration, you hide a target that you touch from divination magic. The target can be a willing creature or a place or an object no larger than 10 feet in any dimension. The target can’t be targeted by any divination magic or perceived through magical scrying sensors.
Notice the period after magic in both instances. You are hidden from Divination magic. That is separate, and then a new sentence. You can’t be targeted by such magic or be perceived through magical scrying sensors.
You are Hidden from Divination magic. That is the very first sentence and it answers it 100% If it is Divination magic then it does not matter if it targets you or not. The second sentence is just to add more and clarify something else. Also true seeing basically turns your eyes into magical sensors so again, it would not work IMO.
The spell does not “turn your eyes into magical sensors.” It grants truesight, which has its own rules — and those rules include seeing invisible creatures. Nondetection has no bearing on a creature’s truesight, temporary or not. Jeremy’s just plain wrong on this one.
I can understand not wanting a 3rd level spell to completely block a 6th level spell … but if true seeing doesn’t get blocked by nondetection because “it’s a divination spell that targets you not the invisible person” … then 2nd level see invisibility is also not affected by nondetection for the same reason.
I can see the balance issues on both sides. If it were my table, I would rule that nondetection will block you from being seen by divination spells (no matter who is targeted by the spell) so long as the nondetection spell was cast at a spell level equal to or more than the divination spell being cast. That way you aren’t hiding from any gods, and while you could hide from a true seeing spell, you’d also have to sacrifice a 6th level spell or better to do so.
Let’s put this one to bed. Obviously your DM is going to make rulings based upon the stuff you are finding as well as the skills in play or the thick of the ommiomenmt.
In AD&D, good ole’ first edition, Non-Detection was an illusionist spell. It was third level. I believe this was the first version of the spell, it’s certainly the earliest I recall hearing about it. It was a personal spell, so only Illusionists could receive it. It only lasted one term per level, but it did ahave an area of effect, 5 feet around the caster. The spell had specific limitations–It made the illusionist invisible to the spells clairaudience, clairvoyance, detect good, detect evil, detect magic, detect lie, detect snares and pits (strange spell, huh), Detect Thoughts (called ESP then), and Detect Invisibility, as well as magic items duplicating these effects (but not psionics). Let that be your guide here.
Now the current version says that the target is hidden from divination spells. It goes on to say that the target of the Nondetection spell, an abjuration, cannot be targeted by divination spells or perceived thru scrying sensors. Keep in mind that Nondetection is a ward, and as such it should not be used offensively and it won’t work in ways not intended.
Pardon my editorial comment here, but I’d sure like to have a spell that prevents one or two of the other schools from functioning at all on my characters besides Mind Blank. An anti-evocation ward would be pretty darn awesome (nut note that energy immunity did not make it into this edition). Likewise, it is almost reasonable that an anti-Necromancy.spell could exist, but instead there are spells that prevent or protect against specific spells and not the entire freakin’ school of magic. .
The new language seems exceptionally generous, let me illustrate why.
The spell definitely impacts any spell that produces a scrying sensor by making the target un-targetable (so you can’t use them as the focal point of the spell) and making the scrying sensor blind and deaf with regards to them. The spells that involve scrying sensors are Arcane Eye, Clairvoyance, and Scrying.
The obvious rule as intended here is that the target be hidden from magic that seeks to reveal information. Abjuration spells create exceptions in their design, so it is reasonable to permit Nondetection to block some Divination effects but not others. In pursuit of the ROI and the nature of warding magic, I think the following spells would be foiled by a creature that took the time in advance to cast a spell that keeps them hidden: Comprehend Languages, Detect Evil and Good, Detect Magic, Detect Poison and Disease, Detect Thoughts, Find Traps, Foresight*, Hunter’s Mark, Identify, Locate Animals or Plants, Locate Object, Locate Person, Rary’s Telepathic Bond, and yes, See Invisibility.
I oppose including True Seeing to this list because it is a specific foil to invisibility, which is an effect that makes you blind with regards to a target. That’s the same mechanic used by non-detection, and True Seeing is several levels higher. It is also one of the pinnacles of the diviner’s art, and to let abjuration trump it at 3rd level is outright ridiculous.
The other pinnacle of Divination is the Foresight spell. But Foresight is not a foil for invisibility. And to be perfectly blunt, I think that spell needs a legitimate foil, which is why I put it on that list. I would let the Nondetection spell grant the power to ignore the advantage and disadvantage mechanics of Foresight.
I violently oppose the use of the spell as a foil for spells that have nothing to do with things that are hidden. Specifically Mind Spike and True Strike.
Also, any Divination that goes about gathering the information indirectly should have no problem working thru the nondetection spell. These are spells that contact intelligences beyond our understanding. The list includes: Commune, Commune with Nature, Contact Other Plane, Divination, Find the Path, Legend Lore.
Note that, as written, having a Nondetection spell on you would also block the use of the following spells by yourself, as you could not target yourself with Divination magic and these spells all have ranges of 0 or touch, or some personal effect on the recipient created by Divination magic. Augury, Beast Bond, Beast Sense, Commune, Commune with Nature, Comprehend Languages, Contact Other Plane, Detect Evil and Good, Detect Magic, Detect Poison and Disease, Detect Thoughts, Divination, Find the Path, Foresight, Fortune’s Favor, GIft of Alacrity, Guidance, Legend Lore, Locate Animals or Pllants. Locate Creature, Locate Object, Scrying, See Invisibility, Speak with Animals, Telepahtic Bond, Tongues, and True Seeing, This interpretation is pretty much ridiculous. The spell description should strike that line
Just my opinion, though.
Good Luck!