Diyu is the realm of the dead or "hell" in Chinese mythology. It is loosely based on a combination of the Buddhist concept of Naraka, traditional Chinese beliefs about the afterlife, and a variety of popular expansions and reinterpretations of these two traditions. The concept parallels purgatory in certain Christian denomininations.

In religion and folklore, hell is a location or state in the afterlife in which souls are subjected to punitive suffering, most often through torture, as punishment after death. Religions with a linear divine history often depict hells as eternal destinations, the biggest examples of which are Christianity and Islam, whereas religions with reincarnation usually depict a hell as an intermediary period between incarnations, as is the case in the Indian religions. Religions typically locate hell in another dimension or under Earth's surface. Other afterlife destinations include heaven, paradise, purgatory, limbo, and the underworld.