Ion is a fictional character, a DC Comics superhero. Created by writer Judd Winick and artist Dale Eaglesham for Green Lantern (vol. 3) #142, Ion was devised as the new superhero identity for Green Lantern protagonist Kyle Rayner. It was later revealed to be able to form mutualism with a host, bestowing its power to a host willingly. This followed a similar retcon as Parallax, originally the new supervillain alias of Hal Jordan, which was revealed to be a parasitic embodiment of fear in the 2004-2005 miniseries Green Lantern: Rebirth.
As soon as sentient beings developed willpower, Ion was born, from the green wavelength of the so-called "emotional spectrum". Its existence has been kept a secret for eons, and it resided in the Central Battery on Oa to keep Parallax, the parasitic fear entity also imprisoned there, in check, as well as granting the Guardians of the Universe, Manhunters, The Green Glob, Halla's, and then The Green Lantern Corps a portion of its vast powers. After Hal Jordan, under the influences of Parallax and Sinestro, destroyed the Central Battery, Ion, along with Parallax and Sinestro, were set free. After wandering throughout the cosmos, it eventually settled within Kyle Rayner as its host.
Kyle first assumes the Ion identity after a prolonged series of events stemming from the death of his girlfriend Alex. First, he unconsciously expels all his feelings of rage from himself, which takes physical form as one of Kyle's childhood nightmares and calls itself Oblivion. Kyle defeats Oblivion in the Circle of Fire storyline, and his powers are boosted as a result. Over time his powers begin to grow even stronger until Kyle realized he is tapping into the Green Lantern energy left in the sun after Hal Jordan died. After a battle over control of the power with the villain Nero, Kyle absorbs all the powers of the Green Lantern Corps, resulting in Kyle taking the name Ion.
Kyle uses his newly expanded abilities to recreate the Guardians of the Universe on the planet Oa, whom he places in the care of Ganthet and orders him to teach them humility, and then recharges the Central Power Battery on Oa. Kyle divests himself of his new abilities soon afterwards when he realizes he is losing touch with the people he was protecting.
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