Demoness Eris is a Dwarf Demon who once engaged in a wager with Demon Pluto on whose planet would be discovered first by mundane astronomers. She was going to win until her lover Demoness Sharon betrayed her and lead the astronomers to find Pluto first instead of Eris. Pluto locked her away under Castle Roogna which she could not escape until a prince married her. She had been locked under Castle Roogna for over a century. Eris and Pluto made another wager on the repair of the cable. When she won, she married Jumper, who had been elected as an honorary Prince of Spiders. She was now free.