Mozenrath is an evil, power-hungry young sorcerer. He is the ruler of the Land of the Black Sand, a kingdom where the sand is black, the sun is usually blocked by clouds, and the only residents are himself, his flying eel sidekick Xerxes, and an army of Mamluks, undead soldiers who are under his command. He is quite open and accepting about his own cruelty and he prides himself on his ruthlessness. He took control of the Land of the Black Sand from its former ruler, the sorcerer Destane. According to Iago, Destane was a real hard case and even Jafar steered clear of him. Mozenrath explained that Destane was like a father to him until he "stole his power and his humanity," turning him into one of his undead soldiers. This implies that Destane was his master until Mozenrath betrayed him, killed him, and turned his body into a zombie. However, the actual story is a mystery. Nobody knows exactly what happened, just that Destane is a zombie now, Mozenrath has his magic, and he's ruling in his place. His floating Eel familiar Xerxes (voiced by Frank Welker) and his undead Mamluk army are loyal to him and will follow any of his orders. His main goal is to conquer and rule the Seven Deserts, including Agrabah. While he and his undead Mamluk soldiers have secure control over the Land of the Black Sand, they are not powerful enough to conquer the other kingdoms that Mozenrath wants to rule. Because of this, his plots and schemes usually involve obtaining more magic and becoming more powerful, and it is up to the heroes to stop him. Through the course of the series he tried to kill Aladdin and his friends whenever they got in the way of his plans, nearly succeeding on several occasions, only to be defeated in the end.
It would have been easy for him to kill Aladdin at any time simply by teleporting to where Aladdin was and finishing him, but he did not, perhaps because Aladdin and his friends spared his life whenever they defeated him. Nevertheless, he does try to kill Aladdin and his friends on several occasions when they are about to thwart one of his schemes or have just succeeded in doing so. Because Aladdin and his friends are good guys, they never kill Mozenrath, allowing Mozenrath to return to his own devices after he is defeated. The last time they defeated him, after becoming fed up with his repeated attempts to harm them, they took away his gauntlet, the source of most of his magical power. Genie then trapped him in a cage attached to a giant balloon and sent it flying away. It is unknown what happened to Mozenrath after this. All we know is that Mozenrath survived the balloon cage because genies can't kill.
Mozenrath is one of the members of Jafar's organization group that still attempts to conquer the Seven Deserts including Agrabah. The reason why Mozenrath joined the Organization was both to gain ultimate dark power and get vengeance on Aladdin and his friends. Mozenrath is also a member of the Sorcerer's Society.