Yu-Gi-Oh! ZEXAL Episode 99: "Restart the Airship! Aim for the Legendary Numbers!!"
Mach was a once pegasus along with his partner Dumon as a legendary hero leding other knights into protecting the peace of the land until one day he returned to his home town. When Dumon and Mach one day returned to arrest the men, they did not listen and attacked him. Because Dumon was not willing to kill their former comrades, the hero and his pegasus, who tried to protect him, were killed. Before dying, the hero with his body to protect his Pegasus, refusing to leave. The gentlemen were so sorry for their actions left their ambition, and buried the hero and his Pegasus together. Mach later became the spirit guardian of the "Number", "Number 44 Pegasus Celestial".
Yu-Gi-Oh! ZEXAL IIEdit
As Yuma and Co. heading to their first location of Number, they end up becoming separated from Shark and Nasch, forced to go down separate paths. Yuma's group ends up in the legendary Number's chamber, where it is protected by its guardian, Mach, who challenges Yuma to see if he is worthy. Making matters worse, the walls in the room Shark and Dumon are trapped is start closing in, requiring Yuma to win quickly in order to save them. Yuma's attacks help open the way for Shark and Dumon to escape to safety, but come at the risk of receiving damage from Mach's traps and spells. After Yuma summons out Utopia, Mach brings out his own Number, Number 44: Sky Pegasus, which forces Yuma to take more damage to keep Utopia on the field. As Shark and Dumon make their way through each room, they find murals depicting a tragic legend about a white pegasus. Wanting to learn how the legend ends, Dumon urges Yuma to keep protecting Utopia, believing the legend is about protecting your friends. Although Dumon's true identity is revealed as he recovers his energy, and his Baria Lapis is repaired, Yuma chooses to protect Utopia. With Astral helping Yuma find a loophole in Mach's combo, Yuma manages to bring out Utopia Ray Victory and win the duel. Mach explains the rest of the legend before leaving Yuma with the Number card.