Nightwatcher

The Nightwatcher is a figure of Rosharan folk belief in the Stormlight Archive, part of the world's common lore from The Way of Kings. The stories agree on the essentials: she is to be found in a valley in the west of the continent, and those who seek her out receive the Old Magic, a boon and a curse together. One request is granted, in her own fashion, and something else is taken or twisted in payment, and neither half can be chosen nor undone. The Vorin church condemns the practice outright, classing the Old Magic among superstitions and worse, yet the pilgrimages continue quietly, and most communities know a story of someone's cousin or grandfather who went to the Valley and came back changed. What the Nightwatcher herself is, no one claims to know.