Fusion is a super villain in the MAD Comics Universe. He is the enemy of Mutant. Fusion is actually a brilliant scientist named Justin Williams. He created the Fusion suit and when he tested it, he became mad with power. He now wears the suit to wreak chaos and try to defeat Mutant.
Justin Williams was a brilliant scientist working for BLC Laboratories. While testing his new Fusion Suit, he suddenly became power hungry, and rampaged through the streets of Kingston. Mutant showed up and was able to remove the suit from Williams. But the radiation from the suit had caused Williams brain damage, and he vowed to kill off Mutant for all. While in jail, Williams managed to build a makeshift Fusion Suit using scraps from the junkyard and a generator. He escaped the jail, and rushed to his labs to bond with the original Fusion Suit. As he was recharging, Mutant confronted him and destroyed the Fusion Suit. Justin escaped the Blast, and vowed to make Mutant pay.
Williams was spotted later hauling all his equipment from BLC to the sewers. He wasn't spotted for a few days, until suddenly there were explosions all over the sewer system. Mutant goes to investigate, to find Fusion in a all new suit. This time its made of pure metal, and able to shoot radioactive bombs.