In the mirror universe, Ruk was an ancient android constructed at least one million years ago by the Old Ones on Exo III. He was the last surviving member of a society of androids which had turned on their masters and killed them hundreds of thousands of years ago.
During a visit to Exo III in the 2260s, Captain James T. Kirk of the ISS Enterprise destroyed Ruk. In 2371, an archaeologist for hire named Jean-Luc Picard speculated that if it were not for Kirk's actions on the planet, the Terran Empire may have been conquered by androids rather than the Klingon-Cardassian Alliance. (TNG - Mirror Universe novel: The Worst of Both Worlds)