Long ago, Shao Kahn once served as an adviser to Onaga when the latter ruled Outworld as the Dragon King. Onaga's Empire had become the most powerful among all of the realms, and so he began searching for a way to become immortal. Before this goal could be realized, Shao Kahn made his move by poisoning Onaga and taking his kingdom. Leading whatever troops that remained loyal to the Dragon King, Kahn continued many of the former emperor's plans. He continued to add lesser realms to Outworld, either through direct conquest or through Mortal Kombat.