Theriana is a powerful human wizard in the service of Lolth.
Very little is known about this enigmatic figure. She is tall, with piercing green eyes, long blonde hair, and an almost unnaturally beautiful face. She has typically been seen wearing black robes, and while the extent of her magical skill is unknown it is certainly very high. She was at the forefront of the search for the scattered keys to Lolth's prison, and encountered the Brightstone Heroes on a number of occasions, though never engaged them in direct combat. A genie claimed he had once been enslaved by her, and described her home as being a massive, spectacular city. However, when he sent the heroes there, they arrived in the ruins of Estorium.
More recently, she approached the Challengers of the Unspeakable outside of Silverstone, claiming to know a means of closing the Far Realm portal opened by Tephra. When they agreed to help her, she sent them to the Tomb of Horrors to bring back Acererak's skull.
She appeared again during the Battle of Silverstone, offering her aid to the Challengers of the Unspeakable in exchange for Acererak's soul gems. When they refused, she departed after promising that she would get those soul gems. That night, she attacked and captured Myra, promising her safe return in exchange for the soul gems.