The Avnilians are the natives of the planet Avnil. The inhabitants of Avnil were a primitive cave-dwelling people whose warriors wielded spears and simple dart-guns and wore imposing domed masks. The caves that they lived in were former mines that permeated the hillside for miles and contained a number of cave paintings about their history and the old gods (Goa'uld). At the time that the SG-9 team arrived, the people had become so numerous that they were outgrowing their caves, but they did not have the technology to extend the mines. SG-9 and, later, SG-1 each found an Solar radiation shield which when activated together would produce a force field over the valley in which the inhabitants lived and provide UV protection. The devices had not been in use for a very long time, and it was not known why they may have been turned off.
When SG-9 first appeared, the inhabitants bowed to the Tau'ri, believing that they were gods. Eventually Captain Jonas Hanson took on the role of a god and subjected the people to his will—instructing them to build a shrine in shifts during both day and night. Samantha Carter and Jack O'Neill were captured and used by Hanson to activate one of the force field devices. He intended to execute them afterwards, but when SG-1 revealed Hanson to be a false god, the inhabitants threw him to his death into the opened Stargate (The iris on Earth was still closed). The members of SG-1 were released and allowed to return home. (SG1: "The First Commandment")