1979’s A Shadow of All Night Falling is the first book in Glen Cook’s A Cruel Wind fantasy trilogy, set in his Dread Empire secondary-universe.
The great city of Ilkazar actually heeded the grim prophecy that the city and its grand empire would fall because of a witch. Every witch, real or supposed, who fell into Ilkazar’s hands was prudently burned alive. Problem solved … or so the city’s rulers thought.
Varthlokkur’s mother was one such witch. The authorities took mercy on the boy, handing him over to doting foster parents. The bright young boy grew into a taciturn, grim, focused adult.