Kahless (Excalbian)
In 2269, this image of Kahless the Unforgettable was created by the Excalbians in a  devised to better understand the concepts of "good" and "evil", with Kahless, ,  and  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.

This replication of Kahless, drawn from the minds of Kirk and Spock, was considerably flawed from the original Kahless, with such notable discrepancies as being infected with the Klingon augment virus, as well as wearing a 2260s-era Klingon Defense Force uniform. The Excalbian version of Kahless appeared and acted quite differently from the original, since the image had been created from reading the minds of Humans who, at that point in Starfleet history, saw Kahless as a ruthless tyrant, and had had far more contact with Augment Klingons (or their descendants) than with standard Klingons. The Excalbian version of Kahless also had a talent for mimicking voices. 

After Kirk killed Kahless and Green, Khan and Zora retreated. Upon viewing this, Yarnek, the Excalbian representative, observed that "The others have run off. It would seem that evil retreats when forcibly confronted." ()

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Excalbians