Emerald Twilight

After Coast City is destroyed, Hal Jordan uses his ring to rebuild it, and the Guardians reprimand him for it. Hal snaps. He flies to Oa, takes the rings of every Lantern who gets in his way, kills Kilowog and Sinestro, and absorbs the Central Power Battery.

With the Corps and the Guardians gone, Ganthet, the last Guardian, gives the final ring to a young artist named Kyle Rayner. It's one of the most controversial stories in comics, and Green Lantern: Rebirth later revealed that Hal was possessed by the fear entity Parallax.