The Emperor's Knife: Book One of the Tower and Knife Trilogy

There is a cancer at the heart of the mighty Cerani Empire: a plague that attacks young and old, rich and poor alike. Geometric patterns spread across the skin, until you die in agony, or become a Carrier, doing the bidding of an evil intelligence, the Pattern Master. Anyone showing the tell-tale marks is put to death; that is Emperor Beyon's law...but now the pattern is running over the Emperor's own arms. His body servants have been executed, he ignores his wives, but he is doomed, for so...