Korris.
Korris was a captain in the Klingon Defense Force in the 24th century. He became disillusioned with the attitude of peace within the empire, and what he perceived to be the loss of the traditional warrior ways of his people.
In 2364, along with Konmel and Kunivas, he stole the Batris, a Talarian freighter, and set off to find a world where he could fulfil his destiny as a warrior. When the IKS T'Acog was sent to bring him back, he destroyed it in a battle, but was only rescued from dying aboard the heavily damaged freighter by the timely arrival of the USS Enterprise-D.
On board the Enterprise, he attempted to convince the Klingon Starfleet officer Worf to join them in their "quest for glory". Another Klingon cruiser, commanded by K'Nera, was sent to capture the fugitives. On hearing of their criminal status, Captain Jean-Luc Picard ordered them arrested, but Korris escaped from the brig, and went to engineering where he threatened to destroy the ship. He was killed by Worf, who refused to help him take control of the Enterprise. (TNG: "Heart of Glory")
Background
Korris was the first character played by Vaughn Armstrong in the Star Trek Universe. In a minor bit of discontinuity, Picard sometimes refers to Korris as "commander," even though the Klingon introduced himself as "captain."