Lancelot

Saber's True Name is Lancelot, also known as the Knight of the Lake (湖の騎士, Mizūmi no kishi), the person serving as a negative symbol of the Arthurian legend. The "Knight of the Lake", admired as the strongest even among the Knights of the Round Table. He was extremely loyal to King Arthur as one of the Knights of the Round Table. Lancelot's downfall began when he fell in love with Artoria's queen, Guinevere. It is said that the tragic love story of Diarmuid Ua Duibhne and Grainne later became the story model of Guinevere and Lancelot.