Galahad

Galahad is a knight whom Ciri met after leaving Geralt and Yennefer on Malus Island. He encountered her in a valley called Cwm Pwcca, at the foot of Y Wyddfa, mistaking her for the Lady of the Lake. He introduced himself as Galahad of Caer Benic, Knight of King Arthur, son of Sir Lancelot du Lac and Elaine daughter of King Pelles lord of Caer Benic.

At the end of the The Lady of the Lake he leads Ciri to Camelot and the court of King Arthur.

In Something Ends, Something Begins non-canon short story)
Galahad became lost in the mists searching for Avalon and an unexpected guest at Geralt and Yennefer's wedding. The young knight is searching for the Holy Grail and mistook the ruined castle of Rozrog for Montsalvat. He also mistook king Herwig for the Fisher King.

He helps Ciri defeat an ilyocoris which has capsized the boat in which Herwig and Loki were fishing. He then pledges himself to Ciri, who strangely does not seem at all unhappy with the arrangement.