He-Man and the Masters of the Universe powers to defend Eternia from the evil forces of Skeletor. Skeletor's main goal is to conquer the mysterious fortress of Castle Grayskull, from which He-Man draws his powers. If successful, Skeletor would have enough power to rule all of Eternia and possibly the entire universe. The Mattel company released the original He-Man action figure in 1982; the franchise backstory was developed by the Filmation animation studio. On 1 December 1982, Michael Halperin wrote a "series bible". Some time after, both firms pitched the idea to the ABC network, who turned it down. The resulting series, "He-Man and the Masters of
He-Man be a descendant of King Grayskull (a powerful barbarian and a hero from Eternia's ancient past), who sacrificed his life in order to save Eternia from the Evil Horde and originally wielded the Sword of Power. He was the original owner of Castle Grayskull; his sword was concealed in the castle for centuries before being given to Prince Adam, who inherited his ancestor's own power channeled through the sword (thus giving added meaning to the phrase "By the power of Grayskull..."). This action-figure line combined elements from the He-Man universe into a cohesive storyline with biographies on the figures' packaging.