Knight of Abyss is a a knight that has served the owner of the legendary maze. It's very powerful, merciless. It is later revealed that the Knight of Abyss was formerly a member of the White Knight cavalry knightage that was part of Glastheim Chivalry when Glastheim was still a city. Members of the knightage were turned into undead by Himmelmez. On iRO, this monster is localized as Abysmal Knight.