In Ultima Underworld I, the Avatar met the knights on their level, where they had managed to hold their ranks together. The Avatar joined them after fulfilling some quests, and after killing the rogue knight Rodrick, receiving the Standard of Honor from them. They had also held the Taper of Sacrifice, but mad Zak had stolen it from them. Being a knight opened the armoury for the Avatar, and the other knights shared many interesting mantras.
The knights evacuated when the colony was destroyed, but were never heard of again, indicating that their order in the end had either failed, or was absorbed by the Order of the Silver Serpent or any other order.