The young Lancelot is in the Armory at the Castle Benwick in northern France—his father's castle. He is trying to look at his reflection in a kettle-hat; he thinks there is something wrong with his face, that he is as ugly as a monster. All through his life—even when he is a great Knight—Lancelot will feel like there is a gap at the bottom of his heart of which he is ashamed.
Just as Arthur's tragic flaw is his innocence and belief in the fundamental decency of humanity, Lancelot's is his belief that he himself is fundamentally impure.
Lancelot is fiercely in love with Arthur. When they were embarking for France after Pellinore's wedding, King Arthur had called him over. Arthur had told him that he wanted to create an Order to fight Might, and that he was looking for knights to join. Lancelot had responded that he would very much like to be a part of this order when he was grown.
Lancelot will become one of Arthur's greatest knights. And his commitment to Arthur does stem from a selfish desire to be chivalrous (traditional chivalry), but from an idealistic commitment to Arthur's idea of justice.
Ever since then, Lancelot has been spending every day in the Armory, practicing to become a knight for Arthur. He decides that when he is a knight, he will have a melancholic name—he will be the Chevalier Mal Fet (the ill-made knight).
The Ill-Made Knight will become Lancelot's alter-ego—the self that overcomes him when his fundamental insecurities about his purity rise up.