Defenders of Man

The Defenders of Man are the main antagonists of Starcraft II: Nova Covert Ops. Publicly, they appeared to be a vigilante group dedicated to the protection of humanity from alien threats, in reality they were an anti-Terran Dominion terrorist group dedicated to the end of Emperor Valerian Mengsk's rule.

History
A few years after Amon's defeat. A Dominion General, Carolina Davis, who was an old friend of Arcturus Mengsk discovered a recording of Valerian allowing his own father's death, thus revealing his role in Arcturus' demise. Having been loyal only to Arcturus, she believed Valerian had no right to rule the Dominion and secretly formed the Defenders of Man with other Arcturus loyalists.

Much like the Terran Confederacy and Arcturus Mengsk, the Defenders planted Psi-Emitters on remote worlds with the intention to lure the Zerg to invade. The Defenders would then come in and destroy the Zerg with the intention of looking like heroes. These actions would paint Valerian and the Dominion as a whole as weak and ineffective.

At some point, they had also attacked a Tal'darim outpost, prompting the Protoss group to retaliate against the Defenders.

Trivia
The Defenders of Man, are in many ways, the evil counterpart of Raynor's Raiders. Both of them were in conflict with the Zerg and the Tal'darim, and both sought the end of the Dominion's reign. However, while the Raiders were genuine in saving lives from the alien threats, the Defenders deliberately started alien threats to make the Dominion look weak.