He-Man, the most powerful man in the universe, is also the defender of Eternia. With his mighty Battlecat, he defends Eternia from the evil forces of Skeletor. His powers were given to him by the Sorceress, the Guardian of Castle Grayskull, who is also one of the only people who know his true identity. The other two people who know that Prince Adam and He-Man are one and the same are Man-At-Arms and Orko.

The ruler of Eternia's sister planet, Infinita, Skeletor is always trying to gain control of Castle Grayskull via a portal which allows him to go from Infinita to Eternia. Fortunately for the people of Eternia, He-Man and his friends are always there to stop this evil menace, no matter what his plans may be. Skeletor carries a ram-headed staff with him, and sometimes rides on his own cat, a purple version of Battle Cat named Panthor.

Man-At-Arms, who's real name is Duncan, is the leader of King Randor's Palace Guards. Swift and agile, he is a skilled warrior as well as a brilliant scientist. He spends a lot of his time doing different experiments and inventing many things, but is always ready to help He-Man when a problem arises. He is a friend of the Sorceress, who gave her daughter Teela to him to raise, and is the one who first led Prince Adam to Castle Grayskull.

Orko is a magical being that helps He-Man protect Eternia from Skeletor. Though sometimes his magic spells don't quite work, it was because of him that Adam became He-Man in the first place. Having accidentally arrived on Eternia via a portal, Orko saved Prince Adam from falling into a tar pit. If this had not been done, there would be no Prince Adam and certainly no He-Man. Orko is also one of the only people who knows of He-Man's true identity

Battlecat is the cat on which He-Man rides. Although as Cringer he's afraid of just about everything, as Battlecat he dosen't fear anything and is always ready to lend a helping hand in any situation.

Beastman is a member of Skeletor's army. Though incredibly strong, Beastman isn't very bright and almost never succeeds in capturing He-Man and his friends