The blood plague is a deadly illness mentioned in Shatterglass. The plague became an epidemic right before the fall of the Kurchal Empire far south near what is now Tharios. Due to the death sowed by the Empire, a plague of blood killed masses of people. Tharios was founded in order to counter the Kurchal Empire and the blood plague. They adopted the god known as the All-Seeing and they believed that death taints all that it touches. In order to keep the blood plague from coming back, it became a law that priests had to cleanse everything that touched and came near a corpse.