Lord Logres is the Ultimate version of Artoria Pendragon, King of Knights. In this version she's the Grand Saber. Wielder of Excalibur, the strongest Holy Sword. She received Excalibur from Vivian (the lady of the lake) after she broke Caliburn, the sword of selection, during a fight. She also posseses Avalon, the sheath that represents the Ultimate defense of the planet. 

Very noble, elegant, honorable, chivalrous and dignified. Her only wish is to serve any master who's rightful and noble.