- "In brightest day, in blackest night, no evil shall escape my sight! Let those who worship evil's might, beware my power, Green Lantern's light!" —Green Lantern Corps oath
The Green Lantern Corps is an inter-galactic police force dedicated to protecting sentient life in every form. Established thousands of years ago by immortal beings known as the "Guardians of the Universe" Green Lantern Officers are chosen for their ability to overcome great fear and are given a power ring fueled by the strength of their willpower.
Each member has a great deal of autonomy as to their methods in their jurisdiction, subject to review by the Guardians if they feel the Officer in question has abused his/her assigned authority. The individual Lanterns are responsible for arranging their replacements if they are near retirement or death. If the Lantern dies before that obligation is met, the ring will find and seek another to be trained on its own. In rare circumstances, Guardians will personally go out into the field to recruit a replacement.
The Green Lantern Corps and Sinestro Corps have both arrived in the Metropolis Historic District. Both corps have been experiencing strange power disruptions with their power rings, suspecting that the cause lies with the other.
- Deep within S.T.A.R. Labs, Brainiac seeks to control experimental devices that will allow him to harness the power source behind the Lantern Corps' rings. This attack throws the Lantern Corps into chaos, and players must join a fragile truce between the Green Lantern Corps and the Sinestro Corps to bring the powerful devices back under S.T.A.R. Labs control.
- As a hero, you will team with the Green Lantern Corps and battle the Sinestro Corps in the streets surrounding Metropolis City Hall. Once inside City Hall, you will join the fight alongside John Stewart to defeat Sinestro.
- Villains with fight the Green Lantern Corps around Metropolis City on behalf of the Sinestro Corps. This will culminate in Villains fighting John Stewart alongside Sinestro.
- Villains will again fight the Green Lantern Corps as they guard captured Sinestro Corpsman and fallen Manhunters.
- The Green Lantern Corps first appeared in Showcase #22 (October, 1959)
- While the corps usually has only two (originally only one) officers assigned to each of the 3600 sectors in the universe, heavily-populated and "hot-spot" Sectors like Sector-2814 can have several Lanterns assigned to its protection.
- The corps' power is fueled by Ion an entity that is the embodiment of willpower.