Rupes Oberon, also known as The Keyboard Man, is a villain from Freleng who wanted to be a member of Zadavia's Royal Court.
He presented Zadavia with a national anthem, but was rejected, as Planet Freleng already had an anthem. He used Boötes and his band to make Tech build the Cosmic Guitar to drain Zadavia's powers in order to control the universe. They confront him and his mannequin band at Galaxyfest. He successfully kidnapped Zadavia and got away to use some of her powers to free Optimatus who was trapped in a black hole. He even made the same request about the anthem to him.
Both of them locate General Deuce and they invadePlanet Blanc in an attempt to use Blanc's wormhole technology to take over the universe. He was double-crossed by Optimatus who had General Deuce steal the Cosmic Guitar from him and was imprisoned after the Loonatics questioned him about Optimatus' plot.