Hal Jordan's enemies: Parallax (Green Lantern: Rebirth)

Rayner explained that there is an emotional spectrum from which the collective willpower of the universe is collected by the Central Power Battery, and that green willpower is the most pure. Parallax had lain dormant for billions of years, his true nature covered up by the Guardians to prevent anyone from trying to free it, and thus, it had eventually come to be referred to as simply “the yellow impurity.” This was the reason why the rings were useless against the color yellow. Parallax weakened its power over the corresponding spectrum, and hence only someone capable of overcoming great fear could master the power ring. The Guardians, therefore, selected only such persons to become Green Lanterns.

The Justice League Of America and Justice Society Of America arrived in the rebuilt Coast City to attack Parallax, but the entity inhibits their efforts by causing them to feel fear. The Spirit of Vengeance, however, manages to overpower Parallax, and finally removes the parasite from Jordan’s soul. Needing a soul to inhabit, Parallax attacks Ganthet, while Jordan’s soul is pulled toward the light of the afterlife. Ganthet manages to guide Jordan’s soul back to his corporeal body on the Moon. His soul and thoughts finally clear for the first time in a long time, Jordan emerges from the coffin resurrected as a mortal human, once again taking his place as a Green Lantern, the white portions of his hair even restored to their original brown. He and Sinestro engage in a fierce battle on the Moon. Eventually, Jordan forces the renegade back into the antimatter universe into which he was first banished. Jordan and Rayner then journey to Coast City, where they, along with John Stewart, Guy Gardner and Kilowog, free Ganthet from Parallax’s possession, and imprison the parasite back in the Central Power Battery on Oa.