A Castoff is a body built and used by the Changing God, later discarded in favor of a new body. Instead of dying and decaying when the Changing God leaves a body, a new consciousness emerges from it. There are many Castoffs scattered in the Ninth World, and all of them are also hunted by the Sorrow, who is bent on destroying their progenitor. Castoffs have the unique ability to manipulate the minds of their 'siblings' through the use of particular Numenera, called Meres.