Klingon emperor

In ancient times, the Klingon Empire was ruled by dynastic emperors. The reign of the last Klingon emperor ended in the mid-21st century, after which the chancellor, leader of the Klingon High Council, assumed the leadership of the Empire. Following the "return" of Kahless, the role of Klingon emperor was reinstated as a ceremonial position, to strengthen the hearts of the Klingon people. 

List of known Klingon emperors

 * Kahless the Unforgettable
 * Reclaw (Second Dynasty)
 * Reclaw (the second) (Third Dynasty)
 * Sompek
 * Mur'Eq


 * Kahless (2369- ???)

Background information
In an explanatory memo about Klingons – which Ronald D. Moore wrote to Michael Piller, shortly before working on – the political framework of the Klingon Empire in the 24th century was referred to as including a Klingon Emperor. The memo pointed out, "His role is almost completely ceremonial by custom, and he still retains the reins of power, should he wish to exercise them." ("Sins of the Father" audio commentary, TNG Season 3 Blu-ray)

Dialogue in "Sins of the Father", written before the canon structure of Klingon culture had been fully conceptualized by the writing staff, implies that there was a Klingon Emperor at least as late as 2346. At one point, Kahlest insists to Jean-Luc Picard that Mogh "was loyal to the Emperor" at the time of the Khitomer Massacre.