He-Man and the Masters of the Universe a "life lesson" or "moral of the story" at the end of each episode. This moral was usually directly tied to the action or central theme of that episode. The show was so successful that it spawned a spin-off series, "", following the adventures of He-Man's sister, Princess Adora. Mattel's subsequent attempts to relaunch the He-Man toy line also led to the short-lived sequel series "The New Adventures of He-Man" in the early 1990s, and an update of the series for a contemporary audience in 2002. It is also noted for featuring early script-writing work from J. Michael Straczynski, later
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.