This knight is unable to achieve the Holy Grail, but his son with Elaine, Galahad, is.
In a work by Chretien de Troyes, this man fights with Melegeant and ends up entering a "cart," destroying his dignity. This man dies while acting as a priest in a convent, prompting his friends to go fight in the Crusades. This brother of Ector de Maris is seduced by the Fair Maid of Astolat and renames his castle "the Dolorous Gard". This man kills Gareth and Gaheris, then has an epic battle with their brother Gawain, at the end of Le Morte d'Arthur. This knight is unable to achieve the Holy Grail, but his son with Elaine, Galahad, is. For 10 points, name this man who carries on an affair with Guinevere but is nevertheless considered Arthur's greatest knight.
In a work by Chretien de Troyes, this man fights with Melegeant and ends up entering a "cart," destroying his dignity.
Sir Lancelot [or Sir Launcelot]