The Saint of Duty said, with a kind of hoarse solemnity: “Fresh blood wards. Every night.” You said, too surprised not to sound like a moron: “What?” He said, “Can’t bleed thalergy … not fresh thalergy. Thanergy, easy. Mixed with thalergy … much harder. No bone wards. Blood wards. Understand? Fresh blood wards. Each night. Can’t break those.”

