Can an invisible stalker circumvent anti-divination magic?

Question

The Invisible Stalker is a monster that can be summoned with an upcast Conjure Elemental spell. According to that spell, "It obeys any verbal commands that you issue to it (no action required by you)." The stalker has a trait called Faultless Tracker:

The stalker is given a quarry by its summoner. The stalker knows the direction and distance to its quarry as long as the two of them are on the same plane of existence. The stalker also knows the location of its summoner.

This is not a spell, it is a natural feature of the stalker. Would this overcome magical protection against discovery such as Nondetection, Sequester, or Private Sanctum?

The stalker understands auran, but does not speak it. Does this mean a summoner can summon a stalker, ask it to allow a spell being cast on it, cast telepathic bond on it to be able to communicate with it without requiring language, give it a quarry, and then telepathically ask it where that quarry is to learn their whereabouts?

(Note: I am aware the DM can decide to have an air elemental appear instead of an Invisible Stalker. For this question, assume that either the DM provides the desired stalker or has an NPC summon such a stalker to overcome the PCs precautions against detection.)

Answer 1

Yes.

The text of Nondetections says (emphases mine):

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.

While Sequester's description says (emphasis mine):

When you cast the spell and touch the target, it becomes invisible and can't be targeted by divination spells or perceived through scrying sensors created by divination spells.

And for Private Sanctum we have (emphasis mine):

Sensors created by divination spells can't appear inside the protected area or pass through the barrier at its perimeter.

Since the Invisible Stalker's ability does not rely on spells, on divination magic or on magical sensors (by description), it can circumvent the protection given by those spells.

Answer 2

RAW, an Invisible Stalker's Faultless Tracker overcomes any protection against divination spells, and may overcome other protections depending on the DM's decision as to whether that monster ability is magic, divination magic, or whathaveyou.

That's kinda dumb though.

Several anti-divination spells specifying they protect against spells is likely an oversight rather than an intentional design choice, as monster abilities that detect or scry on things at long distances but are not themselves spells are rather rare and definitely not something you would immediately think of when writing an anti-divination spell or anti-divination component of a spell. It makes little sense that powerful spells designed to make it harder to find someone would work flawlessly vs powerful divinations but are ignored by a creature summoned with spells that are of a similar level.

That is a nice story element at times - backtracking into your own footsteps being foiled by bloodhounds, etc. However, being the blanket situation that always occurs is weird and unnecessary.

If there's some macguffiny way to penetrate a wizard's abjuration spells, whether that's the Spear of Orythiel, summoning a weird planar creature, or calling together the Circle of Forty to straight up punch through them with sheer magical might, that should be up to the DM. Ergo, as a default, I would suggest houseruling monster abilities that locate a creature without a physical means (aka 'magical person finding' vs 'sense of smell') be treated as Divination spells for the purposes of spells which block or alter divination spells.

Answer 3

Sequester and Private Sanctum will not protect against a Stalker.

Nondetection requires a DM ruling.

Sequester's description says (emphasis mine):

When you cast the spell and touch the target, it becomes invisible and can't be targeted by divination spells or perceived through scrying sensors created by divination spells.

Private Sanctum says (emphasis mine):

Sensors created by divination spells can't appear inside the protected area or pass through the barrier at its perimeter.

Since the invisible stalker ability does not rely on spells or on magical sensors, it can circumvent the protection given by those spells.

Nondetection, however, says (emphases mine):

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.

Faultless Tracker says:

The stalker knows the direction and distance to its quarry as long as the two of them are on the same plane of existence.

The ability does not explain how the stalker knows the direction and distance to its quarry. In the case of a quarry protected by nondection, then, the DM will have to decide whether the stalker's knowledge is in fact based on some kind of non-spell 'divination magic' or not. If it is, then nondetection will provide protection. If it is not based on 'magic', or if it is based on magic but not divination magic, then nondetection will not provide protection either.

Answer 4

I think that ultimately it’s up to the DM.

I don’t think I know of any RAW which says this isn’t possible.

It’s a good idea. However, my personal take on this is that it wouldn’t work as the stalker is using magical means of tracking (even though this isn’t a spell, as you pointed out).

My rational for this decision is that it is a magical creature (especially as you’ve summoned it) so most of its abilities are inherently magical. As the entire purpose of those anti-divination spells are to prevent magical tracking I would say they work on these abilities too.

Further, each of these spells doesn’t state that they only block other spells. Rather that they block divination magic, so for me a magical ability would still count.

I’m sure I would make a “rule of cool” allowance for the right situation though.