Black Annis is still one of my favourite 'bad guys' in The Diabolus Chronicles series. Her myth may have begun as far back as the 15th century, and is possibly based around a Dominican nun named Agnes Scott who was described as a 'hermit of the forest' and ran a leper colony.
Though the origins are debated, the myth is clear. She is a vile blue-skinned, iron-nailed monster with a taste for small children, and roams the Dane Hills at night, looking for suitably young flesh. Once she is done with her evening meal, she hangs the skins upon the oak tree in her bower.
It's said that cottages in Leicester were purposely built with small windows, so that Black Annis could only reach in with one arm if a family were so unlucky as to receive a visit. It made it all the harder for her to snatch a child from their bed in the deep of the night, with her iron claws.
Her cries could be heard for miles, giving villagers plenty of time to board up the windows and place protective herbs around the home to keep themselves safe.
'Black Annis was...the work of a nightmare. Her skin blue as a late summer sky and as wrinkled as a crone’s, her beakish nose running to a hooked point that dripped with foul blackness, and her huge eyes a dull silver. Her hair, what of it could be called such a thing, ran with the same fluid that came from her nostrils. The strands reached to her feet, their ends clogged with the debris gathered off the forest floor.' - Excerpt from The Bandalore - Pitch & Sickle Book One.