It's basically the ultimate stealth spell, hides you from any sense and can beat divinations.
That DC for the CL checks is likely to be impossible.
You're looking at 20(ranks)+3(class skill)+5(dex, and that's low for the level)+10(half caster level)+10(competence from items, could actually hit +15 with greater shadow armour)=48.
That requires a nat 20 and a CL of 28, which few things will ever reach.
OK, so, "Impenetrable", except if they make a caster level check... so, it's [Nondetection](https://aonprd.com/SpellDisplay.aspx?ItemName=Nondetection) expanded to all divination spells at SL 9 and costs 25 times as much! Too bad [Mind Blank](https://aonprd.com/SpellDisplay.aspx?ItemName=Mind%20Blank) does the same thing for 24 hours, no material components, and doesn't give the caster check to beat it. Well, OK, so SL 9 spells are generally just rolling a bunch of lower-level spells together and taking away any weaknesses they might have. That's mostly what's going on here, but still, seeing as Mind Blank is doing one of the more significant jobs of this spell so much better really takes the wind out of this one.
So, besides rolling up Nondetection and [Pass Without Trace](https://aonprd.com/SpellDisplay.aspx?ItemName=Pass%20without%20Trace) (both much lower-level spells), into its effect, this spell is basically here to give +8 to +10 for stealth checks, and something you *can't* get from other spells, the ability to use stealth against an enemy with blindsight and blindsense! That's something you can't get from other spells, so spend 1,250 gp per use on it even if it *does* come from [a feat](https://aonprd.com/FeatDisplay.aspx?ItemName=Dampen%20Presence). Oof.
Granted, the feat has a nasty prereq, and you might want to cast this on someone who *isn't* hyper-specialized in stealth because your party's ability to pass undetected is only as good as your least stealthy member not sitting out the whole thing, but then the caster check is going to be pretty easy to beat if they're targeting the fighter in plate mail with no ranks in stealth, while Mind Blank would still defeat divination magic. If you don't want to split the party, Invisibility Sphere, Silence, and Mind Blank still gets the whole group past most things. By levels 16+, you probably have figured out ways to deal with blindsight/sense before now. (Including just casting [Silence](https://aonprd.com/SpellDisplay.aspx?ItemName=Silence) if trying to sneak past anything using echolocation and/or [Negate Aroma](https://aonprd.com/SpellDisplay.aspx?ItemName=Negate%20Aroma) for scent-based blindsense.) I really don't see the need for the huge material component cost when it's mostly just bundling a bunch of much lower-level spells together, or why it should be SL 9, when Mind Blank is so much more definitive.
Still, if you ARE at level 17 and don't mind boiling everything back down to one character having to pass a stealth check with all the other magic powers not mattering anymore, this works at that specific thing, even if it doesn't help the party or in any other situation. Use it if you have to get the thief to steal something from Smaug, this can let him slip around and steal a single coin, causing the dragon to fly into a rage and maybe get killed off by some other party, leaving you able to claim the lair and treasure for yourself. Then this spell might start paying for itself.
Mind you, there's a bunch of 6-level spellcasters who might get impenetrable veil who just don't get most of the other spells you named, they can even get it a level or two earlier than a wizard or sorc. Also a mesmerist or bard is more likely to have the max ranks in stealth themselves rather than needing to prop up a friendly rogue.
I'm not sure how many spontaneous casters want a spell known that costs 1,250 gp per cast in their ultimate spellcasting slot, but OK, I can see maybe some mesmerists or bards being willing to bite that bullet if they're very heavily stealth-focused. It's... 3,650 gp as a scroll spell for them if they didn't want to spend the spell known on it. Ouch. Oh, and that bard or mesmerist is also definitely going to have UMD, so what do you mean a scroll of Pass Without Trace isn't on their spell list? Those scrolls are going to go for like 25 gp or 150 gp, if in their lowest CL, too.
It's got a use case that does actually expand your options, it's just... I *really* don't see the need for such an expensive component cost when it *is* possible to replace with other spells in many possible ways this could be used, and since those uses are so much cheaper, I'm going to definitely want to exhaust those first.
Mind blank is far better...
And for a small bonus to Stealth and the ability to use it without concealment or cover, you also have Blend, which is only SL1 and 10 minutes / level.
I copied this from someone else.
I cannot take credit!!!
1) It grants Hide in Plain Sight. That's actually quite powerful. Someone can be looking right at you, you make a Stealth Check as a free action, and you vanish.
2) It synergizes completely with Invisibility/Improved Invisibility, which is a flat +20 bonus to Stealth. Furthermore, See Invisibility is Divination and thus won't work against you, and Scent or Tracking can't lock down your square.
3) It's nearly as good as Mind Blank against divination effects (arguably better if you include level 10+ spells), if your Stealth Bonus is high enough, and it's easy to juice a Stealth bonus.
4) If your Stealth check is high enough, you can hit something and immediately Stealth back into being unseen and undetectable. That's like Improved Invisibility lasting a minimum of three hours!
5) Your Stealth bonus is 10+whatever your Stealth modifier of the moment is, including all other modifiers. Stealth is one of the easiest Skill Checks to pop to insane levels.
6) Your Caster Level is not your character Level, so if you can juice your Caster Level, your Stealth Bonus granted by the spell just keeps going up and up. Furthermore, the bonus from the spell is untyped, so it stacks with everything.
7) The material component cost is pocket change for effective Improved Invisibility for three hours and more, especially at 17th+ level.
In short, this is an assassin's dream version of combat Invisibility. Unless your enemy has Perception to the Moon, you are undetectable, untrackable, and going to stay that way a long time, even in the middle of a fight.
It's basically the ultimate stealth spell, hides you from any sense and can beat divinations. That DC for the CL checks is likely to be impossible. You're looking at 20(ranks)+3(class skill)+5(dex, and that's low for the level)+10(half caster level)+10(competence from items, could actually hit +15 with greater shadow armour)=48. That requires a nat 20 and a CL of 28, which few things will ever reach.
OK, so, "Impenetrable", except if they make a caster level check... so, it's [Nondetection](https://aonprd.com/SpellDisplay.aspx?ItemName=Nondetection) expanded to all divination spells at SL 9 and costs 25 times as much! Too bad [Mind Blank](https://aonprd.com/SpellDisplay.aspx?ItemName=Mind%20Blank) does the same thing for 24 hours, no material components, and doesn't give the caster check to beat it. Well, OK, so SL 9 spells are generally just rolling a bunch of lower-level spells together and taking away any weaknesses they might have. That's mostly what's going on here, but still, seeing as Mind Blank is doing one of the more significant jobs of this spell so much better really takes the wind out of this one. So, besides rolling up Nondetection and [Pass Without Trace](https://aonprd.com/SpellDisplay.aspx?ItemName=Pass%20without%20Trace) (both much lower-level spells), into its effect, this spell is basically here to give +8 to +10 for stealth checks, and something you *can't* get from other spells, the ability to use stealth against an enemy with blindsight and blindsense! That's something you can't get from other spells, so spend 1,250 gp per use on it even if it *does* come from [a feat](https://aonprd.com/FeatDisplay.aspx?ItemName=Dampen%20Presence). Oof. Granted, the feat has a nasty prereq, and you might want to cast this on someone who *isn't* hyper-specialized in stealth because your party's ability to pass undetected is only as good as your least stealthy member not sitting out the whole thing, but then the caster check is going to be pretty easy to beat if they're targeting the fighter in plate mail with no ranks in stealth, while Mind Blank would still defeat divination magic. If you don't want to split the party, Invisibility Sphere, Silence, and Mind Blank still gets the whole group past most things. By levels 16+, you probably have figured out ways to deal with blindsight/sense before now. (Including just casting [Silence](https://aonprd.com/SpellDisplay.aspx?ItemName=Silence) if trying to sneak past anything using echolocation and/or [Negate Aroma](https://aonprd.com/SpellDisplay.aspx?ItemName=Negate%20Aroma) for scent-based blindsense.) I really don't see the need for the huge material component cost when it's mostly just bundling a bunch of much lower-level spells together, or why it should be SL 9, when Mind Blank is so much more definitive. Still, if you ARE at level 17 and don't mind boiling everything back down to one character having to pass a stealth check with all the other magic powers not mattering anymore, this works at that specific thing, even if it doesn't help the party or in any other situation. Use it if you have to get the thief to steal something from Smaug, this can let him slip around and steal a single coin, causing the dragon to fly into a rage and maybe get killed off by some other party, leaving you able to claim the lair and treasure for yourself. Then this spell might start paying for itself.
Mind you, there's a bunch of 6-level spellcasters who might get impenetrable veil who just don't get most of the other spells you named, they can even get it a level or two earlier than a wizard or sorc. Also a mesmerist or bard is more likely to have the max ranks in stealth themselves rather than needing to prop up a friendly rogue.
I'm not sure how many spontaneous casters want a spell known that costs 1,250 gp per cast in their ultimate spellcasting slot, but OK, I can see maybe some mesmerists or bards being willing to bite that bullet if they're very heavily stealth-focused. It's... 3,650 gp as a scroll spell for them if they didn't want to spend the spell known on it. Ouch. Oh, and that bard or mesmerist is also definitely going to have UMD, so what do you mean a scroll of Pass Without Trace isn't on their spell list? Those scrolls are going to go for like 25 gp or 150 gp, if in their lowest CL, too. It's got a use case that does actually expand your options, it's just... I *really* don't see the need for such an expensive component cost when it *is* possible to replace with other spells in many possible ways this could be used, and since those uses are so much cheaper, I'm going to definitely want to exhaust those first.
Sounds like the perfect spell for a rogue, the only problem would be that the party can't see him
Mind blank is far better... And for a small bonus to Stealth and the ability to use it without concealment or cover, you also have Blend, which is only SL1 and 10 minutes / level.
Blend gets removed once you attack, also mind blank doesn't protect you from blindsense
I copied this from someone else. I cannot take credit!!! 1) It grants Hide in Plain Sight. That's actually quite powerful. Someone can be looking right at you, you make a Stealth Check as a free action, and you vanish. 2) It synergizes completely with Invisibility/Improved Invisibility, which is a flat +20 bonus to Stealth. Furthermore, See Invisibility is Divination and thus won't work against you, and Scent or Tracking can't lock down your square. 3) It's nearly as good as Mind Blank against divination effects (arguably better if you include level 10+ spells), if your Stealth Bonus is high enough, and it's easy to juice a Stealth bonus. 4) If your Stealth check is high enough, you can hit something and immediately Stealth back into being unseen and undetectable. That's like Improved Invisibility lasting a minimum of three hours! 5) Your Stealth bonus is 10+whatever your Stealth modifier of the moment is, including all other modifiers. Stealth is one of the easiest Skill Checks to pop to insane levels. 6) Your Caster Level is not your character Level, so if you can juice your Caster Level, your Stealth Bonus granted by the spell just keeps going up and up. Furthermore, the bonus from the spell is untyped, so it stacks with everything. 7) The material component cost is pocket change for effective Improved Invisibility for three hours and more, especially at 17th+ level. In short, this is an assassin's dream version of combat Invisibility. Unless your enemy has Perception to the Moon, you are undetectable, untrackable, and going to stay that way a long time, even in the middle of a fight.