Nachtmagen

Nachtmagen is an evil form of magic that primarily hagsfiends have access to, and use in a variety of forms.

It was used by the hagsfiends even since the time of The Legends of Ga'Hoole, and was declared a plague to the world since them. Many nachtmagen spells involve dark rituals that need many sinister objects to occur, like the cinders of dead owls or plucked eyes.