Mary's Little Lambs

While the true nature of these creatures remains elusive to the party, they've had repeated brushes with them. They reportedly act as some sort of scout or information gatherer for the hag Mary .
They seem to skulk around on the edge of the party's vision, taking advantage of the eternal night and inclement weather to largely remain hidden. Their most visible characteristics being muscular and clawed 3 toed footprints, along with a singular large, plate sized, green glowing eye.
While only one of these eyes has ever been spotted at a time, multiple sets of footprints, and the reference by Dharrakir of "Mary's Little Lambs" implies more than one.
The first time the party knowingly encountered these creatures was when they came across the ravaged corpse of a wolf along the road, on their first day travelling south from Mudwater. They've seen evidence of these creatures consistently since then, the last encounter during their trek to Dharrakir's Camp, whereupon they attempted to track the creature, only to find its footprints leading into the camp itself.
It wasn't until the showdown at the temple that the party got a good look at these creatures. Scaled and bipedal, with large jaws and a disturbingly large eye, these creatures seemed capable of both mind reading and psychic attacks.  It also appears that not only Mary has these sorts of creatures in her service.