Undoubtedly, the arch-adversaries to the World's Greatest Superhero Teams of parallel planets are these guys. And the tip-off might be their names... the Injustice Gang of the World and the Injustice Society of the World... who bedeviled the Justice League and Justice Society. And they did so under similar circumstances throughout their long and infamous histories as outlaw organizations. How did the shape the face of infamy and illegality?
The original incarnation of these teams was founded by masterminds Libra and Wizard, wherein the former merely manipulated his minions in order to steal the League's powers... whereas the latter wanted a profitable criminal venture which he tried to recruit the Society to evil ends. During the second incarnation, the same five core members Libra enlisted: Mirror Master, Poison Ivy, Tatotted Man , Scarecrow, and Shadow Thief regrouped on board their satallite headquarters... only to be demolished by the League. The Wizard, however, scrapped former allies Brain Wave, Per Degaton, Thinker, Vandal Savage and the Gambler for newer members Icicle, Huntress, Sportsmaster, the Fiddler and Harlequin... each competing for leadership of the team. Turns out, Harlequin betrayed her allies to save her foe whom she loved, Green Lantern.
The third incarnation which we previously considered hatched a scheme that brought two Earth-Prime protagonists, Ultraa and writer Cary Bates, into the tale. While Ultraa unwittingly stole the League's powers while redistributing them to the Gang, Bates utilizing the power given him by the Wizard seemingly dealt a fatal blow towards six Justice Socialites whom the writer disguised as their Injustice foes in a battle with the visiting League. One additional member in these third teamups was Abra Kadabra (who led the Gang from behind the scenes, mirroring Wizard's capacity on his own gang), while the Shade joined the evil Society of his world during this occasion. While Kadabra's plan was to acquire ancient artifacts though his poisonous proxies in order to control Earth-One's natural resources, once more Wizard's plans was simply to plunder Earth-Two's fudiciary resources instead!
A fourth incarnation of the Injustice Society appeared sometime after this, with the Fiddler recruiting Solomon Grundy, followed by four of their allies who avenged the duo's previous defeat. During this case, the four members of Wizard, Icicle, Brain Wave and Thinker were working in concert with Ayrn the Underlord in his attempt to conquer the surface world. Prior to this, the four remaining cohorts pledged that should this venture not succeed, one of them would travel to Earth-One to recruit more felons to aid in their cause to extinguish the JSA.
While there was no fourth incarnation of the Injustice Gang, another organization assumed its place as Earth-One's dominant criminal organization, the Secret Society of Super-Villains! With Wizard slyly working his way into this corrupt confederation, the villains were originally brought together by Darkseid of Apokolips through his henchman Manhunter, although that affiliation deteriorated quickly. The Society would repeatedly battle Captain Comet and others, including during a period led by Gorilla Grodd versus the League. However, one faction led by the Wizard would achieve his earlier goal! After a sidetrip to Earth-Three, he led erstwhile allies Star Sapphire, Blockbuster, Floronic Man and Reverse Flash to Earth-Two to battle the Justice Society individually. Simaltaneously, on Earth-One Mirror Master and Copperhead are hired by the Silver Ghost to recruit Chronos, Killer Moth, Quakemaster and the Sizematic Twins to battle the Freedom Fighters, visiting from Earth-X. In this untold tale, the Fighters defeat their adversaries and return to their homeworld. And a planet away, Wizard's month long campaign leads to defeat.
Back on Earth-One after six months in interdimensional limbo, the Wizard and his lackies are the sole remaining members of the original Secret Society, and hatch a scheme whereby they assume six Leaguers' identities, while the heroes are trapped in the villains bodies This too fails. Shortly thereafter on Earth-Two, three Injustice Socialites (the Shade, Fiddler and Icicle) assemble on Earth-Two to pillage again. Darkseid turns his attention to these rogues confident they would be more obedient than the felons of Earth-One. That tale told previously ended in defeat as had Darkseid's Secret Society.
At this point, there are no further incarnations of either the Injustice Gang nor Society of their Worlds, and the initial core Secret Society of Earth-One and its satellite team on Earth-Two were now defunct. However, they were not finished, for Ultra-Humanite along with his sub-commanders Brain Wave and Killer Frost brought together ten criminals (here pictured) from both Earths to abscond five Leaguers and five Socialites in order to remove heroes from his world (for the reason why this worked, consider this reference). Although succeeding, the Earth-Two Secret Society betrayed their Earth-One colleagues, who returned the favor by releasing their heroic adversaries. This led to one final occurence wherein the Secret Society operated on Earth-Two, which was incidentally the first time they ever appeared on either world. However this and a more detailed history of that similar yet distinct organization, alluded to in this posting, will be considered at another time. Suffice it to say, Injustice never seems to go away but he never lasts long when champions of good stand in the way of such rogues.