Hidden deep within the source code for the new GreenLantern website, information confirms that Green Lanterns villain is Parallax and not Legion as previously believed, it includes the following synopsis:
GREEN LANTERN - In a universe as vast as it is mysterious, a small but powerful force has existed for centuries. Protectors of peace and justice, they are called the Green Lantern Corps. A brotherhood of warriors sworn to keep intergalactic order, each Green Lantern wears a ring that grants him superpowers. But when a new enemy called Parallax threatens to destroy the balance of power in the Universe, their fate and the fate of Earth lie in the hands of their newest recruit, the first human ever selected: Hal Jordan.
IO9 reported on an earlier rumor that in the Movie Parallax is no longer a fear parasite, but rather a soul-eating creature that infests its victims in order to devour them from within. The movie begins with Oan scientist Krona becoming the first Parallax host as the creature escapes from the Yellow Power Battery. The Parallax-controlled Krona then causes Abin Sur's fatal crash landing on Earth, and Hector Hammond becomes infested with a tiny part of Parallax while performing an autopsy on Abin Sur. This is the source of his telepathic powers, and it's what causes him to attack Hal Jordan and Carol Ferris. Parallax ultimately destroys Hammond's soul and fights Hal Jordan in the flesh.