Thirteen

Thirteen is one of the main antagonist of the series. He's the brother of Zero and is the only survivor along with Zero from the massacre in the cave. Like Zero, Albus, and Mercenary, he doesn't use his real name, but instead uses an alias.

Appearance
Thirteen is a tall man with long black hair. He carries a staff with him always. He is usually seen wearing a black robe with a collar around his neck.

Personality
Thirteen is calculating and manipulative. He thinks he is god, and wants everyone to know it. He has no remorse over his actions. Toward the end of the anime, he sees the error of his ways and has a change of heart. He goes along with Zero’s plan to save the Kingdom and becomes her ally.