The Broken Bones Coven are a... hag coven located in Winterwad which aims at destroying the Kingdom of Arden.
Twelve years ago, the coven performed a powerful ritual to make its members a lot stronger, allowing them replace as many human children with their own. This allowed them to replace roughly 500 to 1'000 children over the course of two years, after which the ritual's price was to be paid with many of the hags dying.
Many of the children died before coming of age, but those who will hit 13 years of age will be awakened to their hag nature. The children carry a charm that allows them to go undetected as fiendish creatures.