Mary

A hag that the party encountered east of Mudwater disguised initially as a young woman waiting for her husband and caring for her sisters. When Fork confronted her about the caged children in the cave, and Brian and Tilly both attacked her, she resorted back to her true form before cursing the party's sudden jump to violence, before turning invisible.
As the party freed the children and searched the cave, both Tilly and Vita noticed a sudden pull in their hair, which Tilly surmised was the hag collecting ingredients for some devious spell such as Clone. However, unable to reveal her, and with two possibly poisoned children, Marwa and Lindra, the party opted to ignore the distractions and get them to safety.
The last the party saw or heard from her was a snickering in the woods, or so they thought.
Through Noggie and Dharrakir, the party realized that the strange, large green eyes that they had spotted from time to time, were Mary's. Or at least, related to her in some way, referred to as "Mary's Little Lambs". The nature of these things is still unknown, but they seem to have been tracking the party, and at least one of them entered Dharrakir's camp ahead of them.
This creature was present, along with two others, and engaged the party during their final encounter with Dharrakir.  The party successfully slew it, although the cackling and chittering that came from it suggested that it did not care.