Grail Knights are the top of bretonnian knighthood. Among the best warriors of the Old World, these holy warriors are always paragons of chivalry and justice, and as a result the king of Bretonnia are required to be one of these legendary figures, to ensure that the nation always have a fair ruler.
To become a Grail Knight you must be blessed by the bretonnian patron goddess, The Lady of the Lake, and have drank from her Holy Grail. To do this, a Knight of the Realm, must take on a Grail Quest and thus become a Questing Knight. Questing Knights travel the world, much like the Knights Errant, to ferret out injustice and defeat the enemies of the Land and the Lady.
The time each knight spends on his quest varies, some travel for their entire lives without ever having a single glimpse of the Grails location, while the more lucky ones spend only months. Once the Lady believes the Knight in question have proved himself she will appear before him, often she will come walking down a lake as her name suggests, and grant the knight a sip from the sacred chalice.
Where she appears changes for each knight. Some might meet her deep in the Forest of Châlons, whilst others might not even be in the Old World when she appears before him. Regardless of the location it is always the same result; Once the knight drinks from the Grail he becomes the ultimate knight, shining with a fay light and completely dedicated to the ideals of chivalry.
How a Grail Knight spends his time after this event varies. Some return to their fiefs or dukedoms, whilst others take the job as a household knight, mostly for the king as no Grail Knight would serve one who has not taken a sip from the Grail. Others continue as before, travelling the world, fighting Greenskins, Chaos, Vampires and whatever other evil creatures they might run into. A fourth group founds a Grail Chapel, often on the exact place where they met the Lady, and stays there tending to it for most of their lives, rarely, if ever, leaving the Chapel.