There are many books that have "assimar", "tieflings", vampires, and shifters able to hide their appearance or strangness from the normals of the world, but not from each other.
 Picture certain races able to cast at will "racial" cantrips ["Castings"?], such as Grey elfs able to do a Casting that allows them to take an appearance of a human of similiar look, age, and size to them self.

  Also picture class Castings, that only work on Mundanes, like a clerical Casting to either return a single hp to a mundane or Casting for blessing that only works on mundanes.

My evil sense of humor would include for a fighter to cast the ability to strike one mundane per round per fighters level.  Yes , I know they can do this in first edition.  but I don't limit the existance of mundanes to first edition.  Another idea is the ability in the middle of a Battle to Cast for five out of command mundanes battling on the fighters side into command and allowing these mundanes movement and defence bonuses.

To me the idea of certain Player Races; able to hide from mundanes at will but not from each other or heroes creates a more exclusive group for adventurers.

I even have the idea of seperate Vampyr race that is usually made of mundane, mundane minions of Vampires, unlike the Normal Vampires converted with classes.  Only as I usually have Heroes come either from the minion races (0-level or >1d8 races), these break free of their masters when they begin to show class advancement
This message was last edited by the GM at 12:35, Wed 10 Feb 2016.

   As mundanes don't exist in 3.0-3.75 rules I am thinking that creating them in the Tradition of a new monster.  And as part of these "Monsters" come certain affects that races, and classes have on them.  IE the boundry to explore is the very nature of mundanes. Such a mundane bending cantrip is not a power of the Race or Class but a "weakness" of mundanes.  so a new player can learn that these are not "Community systems"

"Masque"; A magical effect that racial and class bonuses Have on mundanes.
This message had punctuation tweaked by the player at 16:56, Tue 13 Dec 2016.

Basically from a pathfinder stance you are defining a Type/Subtype of monster called a Mundne.  Normally Types are somewhat exclusive, but not definitively.  Specifically, there are Templates which can be applied to monsters/creatures that adjust abilities, affect CR and add Type/subtypes to creatures.  Examples being adding a skeleton subtype.

Mundane subtype:
Special weaknesses
 Non-[mundane] opponents preforming a full attack action have a new option for their attack.  If all targets of the attack are mundane, the attacker may choose to pick a number of mundane targets not to exceed the number of levels of FULL BAB classes, and make one attack against each designated mundane target within range at their full BAB.  This option can't be mixed between Mundane and non-mundane.  Note they must be full BAB levels, a 8th level wizard with BAB +4 cannot attack 4 mundanes with this option, since none of their levels are full BAB.

Mundane abilities:
Unless specified these extra mundane abilities granted, only apply against others with a Mundane subtype.

Mundane Veil: Other causes the target to appear to be a different race than they are.  This does not affect non-mundanes, or mundanes of the same subtype.

Or

Mundane Mask: Other causes the target to appear to be a different race than they are, and there is no saving throw.  However non-mundanes or mundanes of the same subtype receive a saving throw to see through this affect.

Actually one issue I have had with some spells like Disguise...

Technically, Disguise Self does not allow you to change Types... so disguise self would not allow a tiefling, aasimar, or other outsider to appear to be a humanoid, since these are technically different TYPES.

Maybe that is OK for the spell, if there is something truly different out their natures and that somehow limits things beyond the spells ability to change physical appearance.

Otherwise, I'm tempted to rule for 'appearance' based things, Outsiders of the 'Native' type can be substituted for appearance based operations.  [such as disguise, etc.  But not for things like favored enemy, item activation, etc.]
This message was last edited by the GM at 06:05, Sun 08 Jan 2017.

  Part of the issue with Vulnerability to 'Masque Aura" is it only affects mundanes that are not your type.  a Forest Gnomes apparent invisibility in a wooded area to a mundane human does not affect a mundane forest gnome.. Or any Hero, though they still are using the +8 bonus to hide.

I am wondering about the affect that allows 'Fae' to appear other. I almost wonder if it should be limited to appearing human.  But it doesn't quite feel right maybe you at some point have to pick a kind like one a moon or something. You appear when you do the face, you show, it matches the correct race but anyone that knows you will recognise you in your new face.