The elite clan of nobles in Wolfram’s Parzival who were charged to keep and protect the Grail. The eldest son from each generation was chosen to be Grail King – the first Grail King was Titurel, followed by his son Frimutel. After Frimutel, it fell to Anfortas (Wolfram’s Fisher King), to Perceval, and lastly to Perceval’s son Loherangrin.
Other members of the Grail Family included Perceval’s mother, aunts, and uncles: Herzeloyde, Trevrizent, Schoysiane, and Repanse de Schoye. The tradition of the family was that the members not chosen to be the Grail King would disperse from Munsalvæsche and become rulers of various lands.
The family was in command of a group of Grail Knights called Templars. In Diu Crône, Heinrich von dem Türlin re-interpreted the Grail Family as a cursed clan who Gawain saves from a living death.
Sources
Parzival | Wolfram von Eschenbach, 1200–1210
Diu Crône | Heinrich von dem Türlin, c. 1230