Justice League of America

When the villain Starro attacked Earth, it took the combined efforts of Hawkgirl, Wonder Woman, Flash,  and Martian Manhunter to defeat him. As a precautionary measure against future large-scale threats, the group formed a team known as the Justice League to protect the Earth. Later Superman and Batman joined the team and have since expanded their roster.

The Justice League operated from a secret cave outside of the small town of Happy Harbor, Rhode Island. Since then they've had several base of operations including the Justice League Satellite, the Hall of Justice in Washington DC, and the JLA Watchtower base on the Moon. Currently the team operates out of the newly created JLA Watchtower satellite.

Heroes

 * Heroes are recruited into the Justice League and are allowed to access the functions of the JLA Watchtower. They also receive missions from various members of the Justice League. Oracle is the main contact for the team.
 * A small JLA strike force consisting of Steel, Green Arrow, Black Canary, and Red Tornado, is sent to assist the player group in battling Doomsday during the Smallville alert.
 * Heroes can obtain the Justice League Logo as an Emblem if they have completed all of their storyline missions.

Trivia

 * Justice League of America first appeared in The Brave and the Bold #28 (February/March 1960).
 * There have been many offshots of the team such as: Justice League International, Justice League Europe, Justice League Antarctica, and Justice League Elite.