In an early draft of TNG: "Rightful Heir", Data gave the exact date of Kahless' death as 1,547 years ago (from 2369), or AD 822. According to DS9: "Soldiers of the Empire", the Earth calendar year of 2373 coincided with the year of Kahless 999.

Who killed Kahless?

Kahless himself was believed to have been killed after fighting Hur'q soldiers on Boreth, although it is later revealed he survived. He stands down as Emperor, as he felt Martok's accomplishments had made him irrelevant, but would one day return if his people needed him again.

Is Kahless real?

Kahless the Unforgettable (Klingon: qeylIS'e' lIjlaHbe'bogh vay') is a fictional character in the Star Trek universe. He is portrayed in Star Trek: The Original Series by Robert Herron and in Star Trek: The Next Generation by Kevin Conway.