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.)
Best Answer
Yes.
The text of Nondetections says (emphases mine):
While Sequester's description says (emphasis mine):
And for Private Sanctum we have (emphasis mine):
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.