After being exiled to Earth, the ropbotic conqueror Kra decided to get his revenge on the Challengers of the Unknown. He put together a team of former Challenger foes Drabny, Volcano Man and Multi-Man to form the League of Challenger Haters. The Challengers however beat their foes and put them in prison cells in the heart of a volcano. 
However after sometime Multi-Man used a false tooth which contained a device, and he used it to summon his robotic creation Multi-Woman. Thankful to Multi-Man and his creation the band of criminals appoints him leader. Multi-Man concieved an elaborate scheme to trap the Challengers. They used a refrigerator plant to freeze a small valley, and used a fake television broadcast claiming that a new ice age is coming. When the Challengers investigated they were met by a group of robotic dragons that trapped them in a cave-in. Prof rewired the robots and used them to dig free. The plan failed, and they once again found themselves imprisoned. 
Multi-Man engineered a group of infectious mechanical bunnies, called Chemo-Vooids. He sends the creatures after the Challengers the next time they checked their prisoners. The Challenger Haters presumed they had been killed by the Chemo-Vooids, with their enemies dead that continued their plan to conquer the planet. They sunk several ships, and used the cargo to build their own underwater city. But the Challengers were fine and with the help of the Doom Patrol they defeated the band of criminals. They fled and Multi-Man booby-trapped their underwater city with a bomb, but Drabny triggered the bomb and blew himself up. 
Equipment: None known.
Transportation: None known.
Weapons: None known.
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- No trivia.