When Skeletor was first created, he was, as designer Mark Taylor shares in “The Toys That Made Us,” “the very essence of evil.” Filmation’s “He-Man and the Masters of the Universe” series bible describes Skeletor as the last remaining ruler of Infinita, Eternia’s evil twin planet inhabited with demons and monsters. He was an “evil, megalomaniacal, power-mad monster” determined to conquer Eternia. Admittedly, none of this was ever mentioned on the show, but it was the basis for Skeletor’s stories.
Then Mattel launched She-Ra, and for her cartoon debut, they whipped up a being far more powerful and more evil than Skeletor: Hordak.
This villain had been successful in enslaving an entire world –- Eternia’s twin planet, Etheria, which had replaced the never-officially-mentioned Infinita. Hordak had even kidnapped a newborn baby — Adora, AKA She-Ra — and brainwashed her into serving in his army, the Horde. What’s more, he knew Skeletor not as an equal, but as his one-time apprentice.
Skeletor never managed to conquer an entire world, and the magical power he’d amassed had been learned from Hordak. Granted, “She-Ra: Princess of Power” established that Skeletor’s power had grown considerably since his Hordak days, but suddenly this mysterious demonic figure with no real past seemed a bit less intimidating. He’d just been another lackey. A cog in the machine. It was an undermining backstory that has stuck ever since.