He-Man and the Masters of the Universe (1983)

Eternia is a world where myth, sorcery, and technology intertwine creating a realm of scientific wonder and barbaric magic. But the peace of this world has fallen victim to Skeletor, a tyrannical leader bent on the conquest and enslavement of the entire universe. Skeletor commands a crew comprised of the worst villains ever known. With their evil powers at his command, Skeletor plots to possess the one crucial element needed to reach his goal of conquest... the secrets of Castle Grayskull.

In order to protect Grayskull and the innocents of Eternia, a great power has been bestowed upon what seems like an unlikely candidate... Prince Adam, heir to the throne of Eternos. But when Prince Adam holds aloft the magical Sword of Power he is transformed into He-Man, the most powerful man in the universe. By his side is his trusty but timid companion Cringer, who also transforms into the fearless Battle Cat.

To protect his family and friends from harm, Prince Adam must keep his alter-identity a secret. The Sorceress, Man-At-Arms, and Orko share his secret, and utilize it to call He-Man in times of need. With the other heroic warriors at his side, He-Man wages an epic battle to defend Eternia against the evil forces of Skeletor.

The series was produced by Filmation, and with its success launched a spin-off, She-Ra: Princess of Power, a live action movie adaptation, another spin-off The New Adventures of He-Man, and a remake in 2002.