Mizael is a Barian Emperor, one of the seven rulers of the Barian World. His primary mission is to collect the Numbers cards in order to save his world from destruction. He is a dragon tamer who proudly calls himself the true Galaxy-Eyes master, and he sees Kaito Tenjo as his chief rival for that title. Mizael is prideful and arrogant, but he is also straightforward and serious, unlike some of his fellow Emperors who indulge in distractions. When he arrives on Earth, he immediately focuses on his goal and chastises others who let antics interfere with their mission. Despite his serious nature, he enjoys showcasing his powers in an overly flashy manner. He is fearless and fierce, possessing a cunning instinct and keen intellect that make him a formidable duelist. His superior attitude can leave the other Barians cold, but no one questions his dueling skills. His signature card is Galaxy-Eyes Tachyon Dragon, and he uses it to challenge Kaito and his Galaxy-Eyes Photon Dragon to determine who is the true Galaxy-Eyes champion. Mizael is eventually defeated in a duel, and his soul is absorbed by Don Thousand. However, after Yuma and Astral's final duel, he is revived by the power of the Numeron Code.