Agraveil, Agresianx, Grevi, Grex
A Knight of the Round Table found exclusively in the Livre d’Artus.
He was the son of the King of Alenie, and he apparently joined Arthur’s service during the Saxon wars. He embarked on the quest of la Laide Semblance – to remove the Ugly Appearance from a Libyan river when a maiden arrived at Arthur’s court and announced the adventure. Greu was successful, thanks to the assistance of the Wise Lady of the Forest of No Return.
Afterwards, he married the Wise Lady’s beautiful niece, the messenger who had brought him to the adventure.
Der Pleier’s Garel has some similar adventures, and the names may be related.
See also
Agraveil | The Legend of King Arthur
Source
Le Livre d’Artus | Early 13th century