The ancient guardians of the universe use the Green Lanterns like policemen to keep order across the universe. Each Lantern is given a power ring which receives its energy from a central power battery on the there home world of Oa. For thousands of years the Guardians have been the protectors of peace and justice defending the universe from ancient threats such as the Reach. More recently the guardians went up against the Star Conqueror himself. Starro had taken control of several lanterns and despite the best efforts of the lanterns Guy and Kilowag, Starro managed to gain control of the guardians. Luckily, they were all freed from his control when Starro was defeated by Batman, Captain Marvel and Firestorm.