Is this monster too tough? [Pathfinder]

[TheFamilarRaven]

Hello playground. I was planning on using this little monster (http://www.d20pfsrd.com/bestiary/monster-listings/outsiders/demon/demon-shadow) as the big bad for an adventure segment in the campaign I'm running. Problem is, my gut feeling is that my PC's are ill equipped for it.

The party is all level 4. We have:

Kobold Rogue (unchained)/fighter specializing in climbing opponents
Maltora (homebrewed minotaur race) Barbarian
Human gunslinger
half-elf Magus (kensai/blade bound)
and human sorcerer 1/rogue 3 (unchained)


Even if they face this thing solo, with the action economy on their side, I see no way of them beating it with it's CL of 10, it's ability to fly, and the fact that it's incorporeal. The snag is, I don't know of any other creature that works for the intended role this beastie plays in the plot. The party will be "trapped" in a haunted manor, with the idea that they'll eventually figure out that the root cause of the haunting is actually one of the demonically processed residents (that's the plot in a nutshell anyway).

So my question is: Is there a creature that would be both "tough but manageable" for my party, and fit the flavor of "otherworldly possession"? They don't know the bestiaries that well so any creature that "may not be correct but can be re-fluffed" works.

[Ualaa]

Are there clues that the characters can find, as the adventure progresses, that will give them a bit of an edge or a chance against this creature?

Can they find something that will give them more of a shot at success?
Perhaps a previous group had unsuccessfully attempted their mission, but while unsuccessful in the execution they had brought the correct tool for the job.

If the characters decide to research the haunted house, can they get clues.
Even if the clues are only partially effective -- perhaps they discover that most hauntings are done by ghosts, which are incorporeal, and take reduced damage or no damage from numerous attacks.
That's not telling them what they face, but it is giving them the knowledge to overcome its' incorporeal nature by wrongfully assuming it is a different creature but correctly identifying it as incorporeal.

[Geddy2112]

You could always use this (http://www.dxcontent.com/MDB_MonsterBlock.asp?MDBID=369) devil counterpart to a possession demon.

Or you could go with the much weaker, but still otherworldly possessing, umbral Shepard (http://www.d20pfsrd.com/bestiary/monster-listings/outsiders/umbral-shepherd)

[TheFamilarRaven]

Wow that was fast! I only thought to leave clues about how someone was being possessed, not about hauntings in general, so that's good advice. Having access to Ghost Touch would even the odds a bit, as it will allow the precision based damage dealers to contribute more.

If I add in some detail about sunlight being effective they should have the basis to start formulating a strategy.

Edit: and those other creatures look good too! The Umbral Shepard might let me even the odds in terms of action economy too since their are supposed to be other evil spirits helping out...