Volthoom, also known as The First Lantern and formerly as Rami, is the archenemy of the Green Lantern Corps in the Pst-Flashpoint DC Universe and the main antagonist of Wrath of the First Lantern story in Green Lantern Corps and the true main antagonist of the Phantom Lantern and First Lantern story arcs in Green Lanterns.
Volthoom was an ancient being with the ability to warp reality, born on an unnamed world which was about to be destroyed in the reality of Earth-15. He was taken before the Guardians of the Universe, who offered him a position as their agent, known as the First Lantern. However, Volthoom eventually grew prideful and was imprisoned in an unbreakable chamber and wrote out of their history.
After the War of Lights, the Guardians, as part of a plan to replace the Green Lantern Corps, moved Volthoom into lesser constraints. Using Volthoom's DNA, the Guardians created trhe Third Army, a horde fo infectious warriors that nearly assimilated all sentient life in the galaxy before being stopped by the Green Lanterns.
The Guardians later inadvertently freed Volthoom, who captured them and attempted to siphon energy from the Green Lanterns in an attempt to gain enough power to rewrite the universe. However, he was ultimated defeated by the Lantern Corps. He was weakend by Nekron and separated from his connection to the Emotional Spectrum by Hal Jordan. Utterly powerless, Volthoom was killed by Nekron.
In Green Lanterns, it was revealed that Volthoom had survived this ordeal, but lost his physical form, instead appearing as a spiritual being who manipulated Frank Laminski into becoming the Phantom Lantern, before possessing the body of the guardian of the universe Rami, and setting about manipulating Earth's Green Lanterns Simon Baz and Jessica Cru, so that he could enact revenge on the Green Lantern Corps.