Bertram was a very fanatical believer of the cult, and full of bluster. However, he had no clear idea of the true objective of the cult.
Like his father, Bertram was fascinated by the Cult of the Black Earth and joined the cult, becoming an initiate. Thanks to the cultists, the Nettlebee became ever richer.
In 1491 DR, after some adventurers had defeated the earth cultists at the Sacred Stone Monastery, the cult's leaders ordered Wiggan and Bertram to set a trap to kill the adventurers. They spread rumors about a "fire witch" in their fields, burning an old Uthgardt barrow mound, in order to lure the adventurers.
When the adventurers came to investigate the mound, Wiggan summoned an earth elemental to destroy the mound and kill all inside. However, this also awoke a dead chieftain of the Elk Tribe, Javor. Javor rose as a revenant wanting revenge against Wiggan and Bertram. Somehow, the adventurers resolved the situation and Bertram was killed.