Find Dwarthon Lithin, located in the Bane Castle on the island to the Northwest of RD, and say Bane.

Go kill Delwobble, the mad summoner, who is located in the northern part, in the narrow passage before Shadeen, in the Bane Castle's basements. Return to Dwarthon Lithin and say Bane again.
Reward:

• Audience with Bane