Mattel premiered their Masters of the Universe action figures with an elaborate back story in mini comic book form. He-Man lived on Eternia, a fictional planet decimated by war. The Sorceress of Castle Grayskull had entrusted He-Man with weapons to defend the planet����_��s fortress from the evil Skeletor. He-Man possessed one-half of the Power Sword and Skeletor had the other half. When combined, the two halves of the Power Sword provided the key to Castle Grayskull. The comic books supplied a wealth of characters as potential toys and soon Mattel and Filmation launched an animated television series based on the characters and their stories.