Onryo refers to supernatural phenomenon and the religious idea (in some parts) or spiritual notion that if a person dies in an accident or incident, dispute, suffers punishment or execution, or dies after suffering from excessive mental or physical stress caused by another person, and does not reach heaven or nirvana, but remains in this world saddled with strong feelings (grudges, described below),
ある人間が、事故や事件、争乱、刑罰や処刑、他者からの過度な精神的または肉体的圧迫などによって死に至った場合、いわゆる昇天や成仏をせず、強い念（＝怨念。