Sinestro is a supervillain and the archenemy of Green Lantern. Born on the planet Korugar, Sinestro was an anthropologist who was given his power ring by a dying alien, similar to his future nemesis Hal Jordan. Once a member of the Green Lantern Corps, Sinestro helped train then rookie Hal. But in time, he became corrupted by his use of the power ring, going so far as to attack an invasion fleet even after they surrendered and establishing a puppet government on another world. Imprisoned by the Guardians, Sinestro showed his true colors when he attempted to blow up fellow Green Lantern Mogo, a living planet, in order to save the Earth from Despero. He was stopped by Guy Gardener and imprisoned in Guy's power ring.