King Barbo is a character from He-Man and the Masters of the Universe.
Barbo is the king of Phantos, also called the Dark Moon. He was either the brother of Queen Elmora, or at least succeeded her as ruler of Phantos after she abdicated. Presumably his moon, as a satellite of Eternia, is at least nominally subject to the planetary government of Eternia.
Thanks to one of Skeletor's plots, King Barbo became convinced that the people of the Bright Moon were causing trouble on the Dark Moon. He tore up the peace treaty with the Bright Moon and withdrew from the solar mirror project, but out of respect for King Randor and Queen Marlena, he agreed to give Prince Adam 24 hours to find out who was responsible for the incidents before declaring war. Once Adam and his friends succeeded in foiling Skeletor's plot, King Barbo met with Professor Orion to sign a new peace treaty.