An ikiryoh is in Japanese folklore, a spirit that is born of evil thoughts and feelings harboured by a person. The ikiryoh, energized by hatred, becomes powerful enough to leave its source and enter and possess the object of a person’s hatred. Once inside, it kills the victim by slowly draining the person’s energy. The ikiryoh is extremely difficult to exorcise. Rites to drive it away include the reading of Buddhist sutras (teachings).
The Encyclopedia of Ghosts and Spirits – Written by Rosemary Ellen Guiley – September 1, 2007