Although Percivale is one of the three grail knights that come to the grail (or "Sankgreall" as it is called in Malory) castle at the end of the Malory's narrative, Percivale is prevented from entering the final stage of the quest and waits as Galahad attains the grail and heals the wounded king, Pelles:
And therewith a voice seyde, "There be two amonge you that be nat in the queste of the Sankgreall, and therefore departith!"(602)But after they leave Carbonek, they carry the grail with them. While they are in prisoners in the heathen city of Sarras on their return journey, the grail provides them sustenance. Later on, when Galahad is made king of the city, the three knights worship the grail daily.
Selections from Thomas Malory's Morte d'Arthur. Edited by Eugene Vinaver.