Jagar Tharn was a mage-priest at the Temple of Sethiete in Camlorn, High Rock before his ascension to the position of Imperial Battlemage. In 3E 376, he tricked Queen Barenziah of Mournhold to show him the way to Old Mournhold, where the Staff of Chaos was hidden. He then stole the staff and disappeared. In 3E 397, Tharn and Pergan Asuul tried to manipulate the War of Bend'r Mahk to create the Shadow of War, the powerful creature known as Umbra'Keth. However, another mysterious hero with the help of Skelos Undriel and Azra Nightwielder, thwarted his plan.