Excalibur (エクスカリバー, Ekusukaribā) is the obnoxious Great Old One and former member of the Eight Shinigami Legions who presides over the Madness of Anger. Predating the creation of the Demon Weapon race and serving as the inspiration that led to their creation, he is a Mystical Sword and is officially recognized as the most powerful weapon in the world.