Zem is a character in He-Man and the Masters of the Universe.
Zem was a wizard who wanted to marry Lyra, the lovely young daughter of Brindle. Lyra, however, was in love with the young dragon Torm, and she and her father were both upset by Zem's insistence that Torm was nothing but a monster. Brindle told Zem to leave his house and never return, but Zem did not intend to give Lyra up easily. He summoned the demon Braylok to abduct He-Man and prevent him from completing the test for Torm. When Braylok failed, Zem turned into a fly and followed He-Man into the maze in which the test was taking place. He used his illusions to interfere with He-Man's search for the Silver Apple, which he stole when He-Man found it. Being unable to escape from the maze, he was forced to return the Silver Apple to He-Man and promise that he wouldn't cause any more trouble.
Zem, however, had no intention of keeping his promise. In a final, desperate attempt to stop Lyra's wedding, he revived the ancient dragon Shadow Wing and offered to help him destroy Darksmoke. Shadow Wing, however, preferred to work alone, and turned Zem into a toad instead.