The main antagonist. He is an old associate of Zero's who was the only other survivor aside from Zero of the massacre that led to the theft of the Grimoire of Zero. Alike Zero and Albus, Thirteen does not use his real name and opts for his alias. Thirteen's main personality trait is his deadpan face and low voice. Despite this, he shares Zero's mannerisms when it comes to food including being punctual about meals. Since leaving the cave behind, he has become a Court Mage for a local kingdom in hopes of squashing the rogue mages who have learned magic from the Grimoire. However, his motives have come into question as he is manipulating the people in the kingdom he works for.