Hags

Magical beings that can form a coven with other hags to pool their spells, and feed off each others magic.

They can disguise themselves to look like humans.

Rudolph van Richten advised that to kill a coven of hags it is best to isolate one and kill it to reduce the power of the others.

Granny and her daughters were night hags.

Night hags
The most powerful type of hags, they have purple skin in their natural form.