Psychopomp spiritsense ability (unchained eidolon) – invisibility?

[Killian H]

Hi all, quick question about the psychopomp ability spiritsense (that unchained psychopomp eidolons get at level 12). It's a supernatural ability with the following description:

Spiritsense wrote:

A psychopomp notices, locates, and can distinguish between living and undead creatures within 60 feet, just as if it had the blindsight ability

Is this a constant detect undead/see invisibility/true seeing, that sees through illusions and, eg, mind blank as well? I'm GMing an undead-heavy game where one player has this through their eidolon – seems like it makes it impossible to disguise undead with magical or mundane means. Am I right in saying that appearance of life/daywalker/etc would do nothing here as well?

Overall it seems like a powerful 12th level ability to have constantly on! Trying to work out if it's just detecting living and undead creatures without IDing them or more – and if there's any way to fool it.

[Mysterious Stranger]

Spirit Sense does give the ability to detect undead and fight them without penalty, but that is all it does. It does not protect vs illusions or mind blank. Mind Blank only provides protection vs divination magic, it has no effect on anything else. How an illusion works depends on the subs school it belongs to. Using a figment or glamer to fool spirit sense might be difficult. The rules state that you cannot make a copy of something unless you have experienced it. If the undead had Spirit Sense they could easily create an illusion that worked on spirit sense. Patterns and Phantasms are mind affecting effects so will work just fine. Shadow spells are partially real so also will probably work.