In 2269, this image of Genghis Khan was created by the Excalbians in a plot devised to better understand the concepts of good and evil, with Genghis Khan, Zora, Phillip Green, and Kahless the Unforgettable representing "evil". It was Spock who later observed that these figures from history had been created, and registered as humanoid, despite being a product of matter-energy conversion, whereby other Excalbians themselves were used as the source matter.
After Kirk killed Green, Khan and the others retreated. Upon viewing this, Yarnek, the Excalbian representative, observed that "The others have run off. It would seem that evil retreats when forcibly confronted." (TOS: "The Savage Curtain")