Keller is a weaponsmaster of one-handed weapons found in Castle Britannia. The Avatar met him in Ultima IX, where he offered training in the one-handed weapon style for a fee of 300 gold pieces. The Avatar agreed to the deal and after Keller had conveyed his training, they talked about unusual weapon materials and a Blackrock Sword. Keller had heard rumors about this, but suggested to the Avatar to talk with the blacksmith of Britain, Giovanni about the matter.