Nasu (Zoroastrianism)

Nasu (Also; Druj Nasu, Nasa, Nas, Nasuš) is the Avestan name of the female Zoroastrian demon (daeva) of corpse matter. She resides in the north (Vendidad. 7:2), where the Zoroastrian hell lies. Nasu takes the form of a fly, and is the manifestation of the decay and contamination of corpses (nasa) (Bundahishn. 28:29). When a death occurs, Nasu inhabits the corpse and acts as a catalyst for its decomposition. Nasu appears in various texts within the Avesta, notably the Vendidad, as the Vendidad gives particular focus to demons, purification rituals, and the disposal of corpses and other dead matter. Nasu is commonly considered “the greatest polluter of Ahura Mazda’s world.” Belief in Nasu has greatly influenced Zoroastrian funeral rites and burial ceremonies, as well as the general disdain for corpse matter that is harbored within Zoroastrian practitioners.

Druj, meaning “demoness,” is commonly used as a prefix for Nasu and other female daevas. Druj is a feminine Avestan language word meaning “falsehood,” the opposition of asha, or “truth.”Druj is the root for the adjective drəguuaṇt, meaning “owner of falsehood,” which “[designates] all beings who choose druj over asha."Druj is used in various texts of the Avesta, with varying meanings. Depending upon the context, druj may be used to refer to specific demons, or as a general term for that which is false, immoral, or unclean.

The Avestan words nasu and nasa refer to corpses, or other solid dead matter such as nails and hair. Therefore, Nasu’s name literally means “corpse matter.”

Directly after death, as soon as the soul has left a corpse, “the druj Nasu rushes upon” the body, “in the shape of a raging fly, with knees and tail sticking out, droning without end” (Vd. 7:2). As soon as Nasu takes hold of a corpse, the body instantly becomes contaminated. If one comes into contact with a corpse, Nasu will emerge from the body and infect them, rendering them “unclean … for ever and ever” (Vd. 3:14). Nasu continues to inhabit the corpse until the sagdīd ritual is performed, during which a dog must look at the corpse, or until a carrion-eating bird or dog consumes the body, which causes her to return to her home in the north (Vd. 7:3).

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