This lovely blonde damsel sent her uncle the Fisher King a gift, the sword forged by Trebuchet, with the message that she would be well pleased if he passed it along to a worthy recipient. He passed it along to Percivale.
I strongly suspect, but cannot absolutely prove, that she is the same cousin whom Percivale meets next morning on his way away from the Fisher King’s dwelling. She sits mourning her lover, who lies in her lap newly slain by the Haughty Knight of the Heath, and whose body she refuses to leave until she has buried it. Recognizing Trebuchet’s sword, she tells its present bearer much about it and about the Rich Fisher.
This cousin was reared as a young child with Percivale in his mother’s nursery. Now she asks his name: he has not known it (at least consciously) before this moment, but in answering her question he instinctively calls himself Percivale – commentators understand this as a crucial point in his development. His cousin then chides him for failing to ask the questions that would have healed their uncle and spared people a lot of grief.