The Kahless reference article from the English Wikipedia on 24-Apr-2004
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Kahless

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Kahless is a Klingon portrayed in the Star Trek series by Kevin Conway.

The History of Kahless

Kahless (also known as Kahless The Unforgettable) is a Klingon mentioned in many Klingon histories. A clone named Kahless was created from the blood of a dagger.

Supposedly, Kahless was a great warrior who freed his people from tyrannical rule. He also created the first Bat'leth from a lock of his hair that he dipped in molten magma. There was a great war, and Kahless' followers won. However, in the process of ousting Molor (the evil dictator), Molor supposedly stabbed Kahless with a dagger. It was from the dried blood from this dagger that the clone was created.

An image of Kahless was encountered in the TOS episode, The Savage Curtain. In the alien Yarnek's study of good vs. evil, Kahless was one of the evil images alongside Colonel Green and Ghengis Khan. Abraham Lincoln and Surak of Vulcan represented good and assisted Kirk and Spock. Played by actor Robert Herron, this Kahless also appeared as the typical 60s era Klingon. Kahless' depiction here was generally assumed to be based solely on Kirks limited and heavily biased knowledge of Klingon culture. If Yarnek's scenario were to be played out today, Kahless would doubtlessly be placed with Lincoln and Surak and his former place next to Colonel Green might be occupied by Molor or perhaps Duras.

Other Theories

In the book, Kahless, written by Michael Jan Friedman, it appears that Kahless was not the one who was stabbed; the clone is not that of Kahless, but of Kahless' friend, Morath. In the book, Morath is the one who led the rebellion, Morath made the first Bat'leth, and Morath was stabbed and lost his life protecting Kahless. However, this may not be accepted in the general Trek universe.