Request: Creatures that can easily hide in human(oid) society?

[Necrosnoop110]

So homebrewed campaign. The idea being there are no monsters visible out in the open. All of them must hide in plain sight.

Looking for a list of lower CR monsters (below say CR10 or so) that have the ability to blend in and hide within a developed human-level society. Ones that have both a reliable way to disguise themselves and the intelligence to stay hidden in plain sight. That is the need the society to survive and thrive so they can't just wall themselves up, they must engage with the world. Shapechangers like lycanthropes first come to mind.

Any suggestions?

[Tawmis]

Dopplegangers are the first thing I thought of when I read your subject.

[Rukelnikov]

So homebrewed campaign. The idea being there are no monsters visible out in the open. All of them must hide in plain sight.

Looking for a list of lower CR monsters (below say CR10 or so) that have the ability to blend in and hide within a developed human-level society. Ones that have both a reliable way to disguise themselves and the intelligence to stay hidden in plain sight. That is the need the society to survive and thrive so they can't just wall themselves up, they must engage with the world. Shapechangers like lycanthropes first come to mind.

Any suggestions?

Check World of Darkness, the whole premise of the game is basically that. It includes, but not limited to, Vampires, Lycanthropes, Mages, Mummies, and lots and lots of stuff. You can probably glean A LOT of ideas from there.

[Sparky McDibben]

Fey (pretty much all of 'em).
Aberrations (illithid cults, aboleth servitors, kraken minions, etc.).
Celestials.
Metallic dragons (shapechangers).
Fiends (either from shapechanging or cults).
Mimics.
Undead (ghouls who apply makeup and only hunt at night, for example).

[RSP]

Not sure this is quite what you’re looking for but Intellect Devourers come to mind.

[sambojin]

Firbolgs. They get super-Disguise Self (so can look like *any* race) and invis pops, even as a PC. And they have plenty of Druids, for wildshape shenanigans. And talk-to-animals as a basic thingy. And Detect Magic. And are super-strong. You don't have to run them just like a PC has to, you're the DM, but these are basic racial abilities.

They're even premised of sometimes infiltrating towns, but not necessarily antagonistically, though it can be that way as well.

Hidden mini-giants, done!

[Droodicus]

Those gross water guys from saltmarsh

[Mastikator]

Some creatures can cast Disguise Self at will. Rakshasa, Dusk hag, Mind flayer arcanist etc. You could also add "At will: Disguise Self" to any number of monsters that may be vaguely justified to have that.

[Gryndle]

Yuan-ti pureblood can pass for human with minimal or at least very little effort

[da newt]

Oni = nasty too.

[J-H]

The Raggamoffin(sp?) from like MM3 can qualify as this. It's a semi-intelligent pile of magic "stuff" that can take over a body and control a humanoid, kind of like possession.

[heavyfuel]

Medusa, at least in 3e, were indistinguishable from humans when beyond 30ft:

"A medusa is indistinguishable from a normal human at distances greater than 30 feet (or closer, if its face is concealed). The creature often wears garments that enhance its body while hiding its face behind a hood or veil."

No reason you can't adapt this to 5e. They can hide their face when out and about, and be fine