Gorkon
Chancellor Gorkon was head of the Klingon High Council in Star Trek VI: The Undiscovered Country which was a point of great crisis for the Klingon Empire. The moon Praxis exploded, causing great environmental damage to the Klingon capital world Qo'noS, depleting its ozone layer. According to official reports, the planet would soon be completely uninhabitable.
Because of the catastrophe, Gorkon sought help from the Federation for evacuation of Qo'noS and peace talks. The Enterprise was dispatched to rendezvous with Gorkon's ship, IKS Kronos One.
Assassination
Not everyone was pleased with the idea of peace between the Klingon Empire and the Federation, including high-ranking officials in both of the two governments, as well as the Romulans. Gorkon's ship was attacked by a prototype Klingon Bird of Prey that could fire while cloaked, knocking out the battle cruiser's artificial gravity system. Two Federation personnel beam aboard Kronos One and assassinate Gorkon. Kirk and Dr. McCoy transported over to the Klingon ship to assist with damage control and McCoy tried unsuccessfully to resuscitate the Chancellor. Everyone believed the Enterprise was the ship that attacked and Kirk and McCoy are arrested for the assassination.
Gorkon’s last words were spoken to Kirk, "Don't let it end this way, Captain." His daughter, Azetbur succeeded him as Chancellor.