The Number Guardians, known as the Numbers Guardians (ナンバーズのガーディアン Nanbāzu no Gādian) in the Japanese version, are the spirits of the ""Mythyrian Number"" cards in the "Number" ruins within the Yu-Gi-Oh! ZEXAL anime, assigned with the duty of protecting them. In order for a Duelist to obtain their cards, he or she must Duel against their respective guardian to see if he or she is worthy of wielding the "Number". After a guardian is defeated, they usually disappear. They are also related to the Legendary Figures or the cards themselves.