In Perlesvaus, Gawain encounters a descendant of the Greek hero - a knight in the habit of slaying other knights who lodged at his tents. After defeating him, Gawain had to thrust his sword through the sole of the knight's foot in order to kill him. This was apparently the case with all of Achilles' descendants.
Achilles the Blond
This "abbey in the forest of Camaaloth" is the place of Pelle's sister, whom is the abbess. She brings up Galahad.