Atrocitus : In the movie Parallax was trapped in sector 666, the homeworld of Atrocitus. I imagine Parallax destroying the planet and after this being trapped there or the Manhunters battle Parallax and destroy the life in there then enprioned Parallax. Atrocitus is outraged with this and commits crimes that make him be emprisioned in a Green Lantern prision.
Zamarons : A race of females Amazons Guardians. They split from the other Guardians when Krona was corrupted by The fear (yeallow light) and became Parallax. They think Love will overcome Fear and Will Power. One of them have discover the Violet Light of Love and turned it in a stone thay call Zamaron Sapphire.
Manhunters : Robots created by the Guardians centuries before the Green Lantern Corps. They were protected the whole Universe perfectly until Kron, a fallen Guardian, made them malfunction. The Guardians deactivated them unkowing that they would become a great threat in the fucture.
Larfleeze : An alien thief that found an Orange Lantern hiden in a dead planet. He used the Lantern to forge himself an orange ring. The Orange Light gave him the power to turn into constructs all of his victims but also take controll of him.