How does the Hide from Undead spell interact with the effect of an Invisibility Purge spell?

Question

Take a group of adventurers trying to get the drop on a lich or any other intelligent undead. They decide to use the spell hide from undead to get into position. What they don't know is that the undead is cautious and has something producing an invisibility purge effect, like a lantern of revealing.

The hide from undead spell description says:

Undead cannot see, hear, or smell creatures warded by this spell.

But it's not listed as being invisible, and the invisibility spell's school is actually illusion (glamer) whereas hide from undead's is abjuration.

Would hide from undead keep the adventurers from being seen? Or would the invisibility purge effect make them visible?

Answer 1

As written, invisibility purge does nothing against hide from undead. Nothing in hide from undead says anything about invisibility (and, indeed, its protections cover far more than invisibility does), and nothing in invisibility purge says anything about non-invisibility forms of hiding. Subjects of hide from undead may appear as if invisible to undead eyes, but that is not, apparently, how the spell works “under the hood” so to speak.

I could see houseruling things to give the undead more options against hide from undead if it was becoming a problem in a campaign, including perhaps expanding invisibility purge’s scope to cover it, but that would be a houserule and not one I’d bother with in most campaigns.