Shao Kahn
Weary of continuous losses in tournament battle, Shao Kahn, who lost to Liu Kang in the Outworld tournament in the previous game, enacts a 10,000-year-old plan. He would have his Shadow Priests, led by Shang Tsung, revive his former Queen Sindel, who unexpectedly died at a young age. However, she would not be revived in the Outworld, but in Earthrealm. This would allow Shao Kahn to cross the boundary lines and reclaim his queen. When Sindel is reincarnated in Earthrealm, Shao Kahn reaches across the dimensions to reclaim her, and as a result, Earthrealm gradually becomes a part of Outworld, stripping billions of their souls. Only a few are spared, protected by Raiden. He tells them that Shao Kahn must be stopped, but he cannot interfere; due to his status, he has no power in Outworld, and Earthrealm is partially merged with Outworld. Shao Kahn has unleashed extermination squads to kill any Earthrealm survivors. Also, Raiden's protection only extends to the soul, not to the body, so his chosen warriors have to fight the extermination squads and repel Shao Kahn. With his final defeat, every human on Earthrealm is restored.