The Black Grail Knights were the resurrected corpses of twelve long dead Grail Knights of Bretonnia. Greater and more infamous than even the Blood Dragons of the time, they were among the mightiest Undead to have ever walked the Old World.
- "Your souls will join our dark crusade!"
- —The Black Grail.
Grail Knights are considered the ultimate Human warriors, revered throughout Bretonnia and beyond for their purity and honour. If they fall in battle, they are given grand funerals and their souls belong to the Lady of the Lake.
This process meant that normally, Grail Knights were one of the few beings who could not be brought into undeath. Some, however, particularly those whose corpses lay in Mousillon, were vulnerable. Even in the tainted lands of Mousillon, only a being of immense power could hope to molest the natural order of the Lady. That being was the ancient Dread King.
Taking up their fortress in Castle Mousillon, the Black Grail Knights would become legendary. A blasphemous creation, warped into a dark mockery of their former selves, they were extremely powerful warriors who fought relentlessly. Mounted atop the animated remains of their once noble Warhorses, they could not be slowed by difficult terrain and would never retreat from combat. An aura of fear surrounded them at all times, causing enemies to panic and flee in their wake. So deadly were the warriors, that some did not even know they were knights, believing instead that the "Black Grail" was an artifact of immense power and destruction. Many tried to defeat the undead order and all failed.
The Black Grail Knights were eventually destroyed by an army comprised of living Grail Knights led by Tristan de la Tour and the mercenary forces of the Grudgebringers. With the Black Grail destroyed, these former heroes of Bretonnia could finally return to their deserved rest.
One of the shields wielded by these mighty knights was eventually reclaimed from the site of their final battle. Taken up as a powerful dark artifact, it became known as the Cursed Shield of Mousillon.
- The Black Grail Knights are not to be confused with the Knights of the Black Grail, a relatively unknown group of Blood Knights who served as Mallobaude's bodyguard.