He-Man and the Masters of the Universe

Prince Adam is the young son of Eternia's rulers, King Randor and Queen Marlena. Whenever Prince Adam uses the Sword of Power by holding it aloft and saying the magic words "By the Power of Grayskull, I HAVE THE POWER" he is transformed into He-Man, the most powerful man in the universe. Together with his close allies, Battle Cat, The Sorceress, Teela, Man-At-Arms and Orko, He-Man uses his 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 he succeeds, Skeletor would conquer the world of Eternia, and possibly the whole universe.