The pishacha appears already in Vedic and epic Sanskrit literature, including the Ramayana and Mahabharata, as a distinct and lower class of spirit associated with darkness, cremation grounds, unclean places and the eating of raw or rotting human flesh, ranking it among the more feared beings in the wider bhuta-preta taxonomy rather than a merely mischievous or ambiguous ghost.
Some Puranic genealogies count the pishachas as a class of being created directly by Brahma or descended from Kashyapa, giving them a distinct mythological origin rather than treating every pishacha as a formerly human soul, which sets the type apart from the vetala and bhoot; in practice, though, popular and regional tradition often blurs the line and treats a pishacha as one possible fate of a person who died in a state of extreme impurity or violence. Classical Sanskrit drama and poetry occasionally used a language called Paishachi, said to be the tongue of the pishachas, as a literary device, and the Brihatkatha, an important lost Sanskrit story collection, was traditionally said to have been composed in it, giving the creature an unusual secondary life as a linguistic category alongside its mythological one.