About fifteen centuries before the 24th century, the warrior Kahless the Unforgettable killed the tyrant Molor and united the Klingon people, founding the Klingon Empire.
Kahless is remembered as the greatest of all Klingons. According to legend, he forged the first bat'leth, the Sword of Kahless, from a lock of his own hair dipped into lava, and used it to kill the tyrant Molor. He then brought the warring Klingon peoples together under a code of honour that shaped their empire for centuries.
Kahless gave his people their laws and traditions. Before he left, he promised to return one day, and his followers kept faith in that prophecy at the monastery on Boreth.
In 2369 the clerics of Boreth produced a clone of Kahless. Though the deception was exposed, Worf persuaded Gowron to install the clone as a ceremonial emperor. The legend also drove Kor, Worf and Dax to seek the lost Sword of Kahless in 2372.