Nasht is a god of knowledge, represented as a man in robes and an Egyptian-style headdress. He guards the Cavern of Flame between the waking and dream worlds, and knows much of other dimensions. His fellow priest-sentry, Kaman-Thah, is not worshipped, but is considered an avatar of Nasht.
Nasht and Kaman-Thah look young, strong, and handsome, yet they are incredibly old, possibly older than the universe itself. They are omniscient and omnipotent; they could look upon the "face" of Azathoth itself without harm. Within the Cavern their word is law, not even Nyarlathotep can contest them there. However, they are gentle and peaceful. Their purpose is to guard the Dreamlands from evil and corrupt dreamers, and to guard the dreams of men from the horrors of the Dreamlands.
An alternative story goes that Nasht once was a mortal human called Reon Atescre of Sona-Nyl. He was a traveller who once sailed to the harbor city of Lelag-Leng. He was captured by the men of Leng and burnt alive as a sacrifice to the gods. Elder Gods accepted him and returned to Earth as a new entity known as Nasht.