Hector Hammond first appeared in Green Lantern #5. In it, he was still a normal, but genius, man who found a meteor that increased evolution. He used it on four scientists and weakened their wills so they had to obey him. He used their futuristic knowledge for his own purposes, and gave the scientists little credit, if any. By chance, he got a hold of a duplicate power ring and dueled with Green Lantern. However, he lost their fight and wasn't seen for some time. The next time he was seen was in Justice League of America: Menace of the Atom Bomb. It was then revealed that he had evolved himself and because his will was not crushed, he had many mental powers. Since then, he has tried several schemes to defeat GL, such as controlling Sonar and almost defeating GL with him, or taking control of GL's Power Ring, and through it, Green Lantern, making him helpless before him. He also made himself immortal, but at the cost of losing mobility. The most deadly of Hammond's schemes though, was creating a fake Guardian, with all the powers of a real Guardian. GL was close to being utterly destroyed in that battle. Hector Hammond truly is one of Green Lantern's deadliest foes.