Both "x̲'aséikw" and "k̲aa toowú" are mortal, and cease to exist upon the death of a being. However, the "k̲aa yahaayí" and "k̲aa yakghwahéiyagu" are immortal and persist in various forms after death. The idea of "k̲aa yahaayí" is that it is the person's essence, shadow, or reflection. It can even refer to the appearance of a person in a photograph or painting, and is metaphorically used to refer to the behavior or appearance of a person as other than what he is or should be.