The title of the leader of the Klingon High Council and effective ruler of the empire, held in turn by Gorkon, Azetbur, K'mpec, Gowron and Martok.
The chancellor leads the Klingon High Council and with it the whole empire. The office is usually won by the Rite of Succession, and a sitting chancellor can be challenged to combat by a warrior with cause.
In Star Trek VI: The Undiscovered Country Chancellor Gorkon is assassinated on his way to peace talks and is followed by his daughter Azetbur. In The Next Generation K'mpec, who held the office longer than anyone, is poisoned in Reunion and succeeded by Gowron.
Gowron leads the empire through its civil war and into the Dominion War. In the Deep Space Nine episode Tacking into the Wind Worf kills him in a duel over his reckless conduct of the war and hands the chancellor's cloak to General Martok. Discovery shows an earlier holder, L'Rell, who unites the houses after the war of 2256.