Thalynsar was an ulitharid in Ch'Chitl in the mid–13th century DR when a raiding party of githyanki assaulted the city and mortally wounded the elder brain. Taking desperate measures, Thalynsar transformed himself and several other illithids into liches so they could devour the elder brain, preserve its knowledge and powers, and take its place.
Successful in their endeavor, the illithiliches formed a Conclave of Elders, with Thalynsar as the most powerful among them. He tried to retain much of the elder brain's knowledge for him, but the excessive information steadily turned him insane. Nevertheless, Thalynsar ruled Ch'Chitl for over a hundred years.