Masters of the Universe (sometimes referred to as the He-Man or She-Ra series) is a sword and planet-themed media franchise created by Mattel. The main premise revolves around the conflict between He-Man (the alter ego of Prince Adam) and Skeletor on the planet Eternia, with a vast lineup of supporting characters in a hybrid setting of medieval sword and sorcery, and sci-fi technology. A follow-up series, She-Ra: Princess of Power revolves around He-Man's sister She-Ra and her rebellion against The Horde on the planet Etheria. Since its initial launch, the franchise has spawned a variety of products, including multiple lines of action figures, six animated television series, several comic series, video games, books and magazines, a daily newspaper comic strip, and two feature films (one animated, one live action).