|Title:||The Unfading Light of the Lake|
|Maximum number of targets:||1 person|
Arondight: The Unfading Light of the Lake (無毀なる湖光, ?) is a holy sword wielded by Lancelot that is the counterpart of King Arthur's Excalibur. It bears a similar design to that of Excalibur, carved with Fairy Letters to show that it was not forged by mortal hands. It is a limitless sword capable of receiving any attack without taking damage that shines much like the water of the Lake. It was given only to someone who could be exalted as the "perfect knight", the strongest, bravest and truest knight of an era, which signifies the unrivaled Lancelot out of all those who sat at the Round Table of Camelot. The sword has lost its status as a holy sword after Lancelot used it to slay several of his fellow knights who were acting as guards of the execution of Guinevere. His prana, filled with his madness and resentment, has dyed the sword pitch-black and caused it to fall to the state of a demonic sword of a mad warrior. It is Berserker's true Noble Phantasm, which seals For Someone's Glory and Knight of Honor once it is drawn. It increases all of his parameters by one rank and the success rate of saving throws are doubled. Due to the legend in which Lancelot slew a dragon, Arondight deals additional damage to Heroic Spirits like Saber who have a "dragon" attribute.