Crystal

“There are different kinds of darkness,” Rhys said. I kept my eyes shut. “There is the darkness that frightens, the darkness that soothes, the darkness that is restful.” I pictured each. “There is the darkness of lovers, and the darkness of assassins. It becomes what the bearer wishes it to be, needs it to be. It is not wholly bad or good.”
― Sarah J. Maas, A Court of Mist and Fury