Korris was a Klingon villain in the Star Trek: The Next Generation episode Heart of Glory.
By the mind 2360s Korris was a Captain in the Klingon Defense Force. Becoming disillusioned with the state of Klingon society in the wake of the Klingon Empire's alliance with the United Federation of Planets, Korris went renegade. Working with Konmel and Kunivas the three stole the Talarian freighter Batris. The Klingons sent IKS T'Acog after him but he was able to destroy the ship when they lowered shields to beam a boarding party aboard. Korris and his co-conspirators were saved by the USS Enterprise (NCC-1701-D), who arrived in response to a distress signal and signs of a battle in the area.
On the Enterprise Korris and Kommel spun a story that they were hitching a ride on the Batris to a Klingon outpost for Captain Jean-Luc Picard and Lieutenant Worf when the freighter was attacked by the Ferengi. When Worf told them analysis had proved the weapons were Klingon Korris and Kommel insisted that the ship was Ferengi but with Klingon weapons. Picard was still suspicious, but without further proof of malfeasance he had Worf take them to guest quarters. A short time later he had to call them back to sickbay when Kunivas died of his injuries. Picard, Dr. Crusher, and everyone else in sickbay became the first Federation people in history to see the Klingon death ritual as Korris, Kommel, and Worf howled at the dead, warning them a Klingon warrior was about to arrive.
Over the next several hours Korris and Kommel both tried to talk Worf into joining, trying to ply them with stories of glory and honor. Worf was able to get Korris and Kommel to admit the truth - that they had stolen the Batris and destroyed the Klingon ship sent to bring them back. Korris claimed that his brother warriors on the ship had been corrupted by peace, so he had to kill them.
Meanwhile a Klingon ship under the command of K'Nera approached the Enterprise. K'Nera informed Picard that Korris and this compatriots were renegades and that he had come to arrest Korris and his accomplices. Picard had security take Korris and Kommel into custody. Korris briefly took a young girl hostage but remembered that real Klingon warriors didn't take hostages. The pair were marched off to the brig.
While Korris and Kommel were stewing in the brig, Worf tried to persuade K'Nera to not take them home to certain execution, but to maroon them on a planet where they could meet death in an honorable fashion. K'Nera was adamant though, and the Enterprise crew prepared to beam the renegades back on to a Klingon vessel. What they didn't know was that Korris and Kommel had assembled a disruptor from parts that were stashed in their uniforms. Disrupting the force field Kommel was killed by a guard, but that guard was then killed by Korris.
Korris ran off to engineering. Climbing up on to an upper level he pointed his disruptor at the warp core. When Picard told Korris that the escape attempt was futile Korris yelled he would only talk to Worf.
Worf went to engineering where he confronted Korris. Korris tried one last time to turn Worf, but Worf ordered him to put down his weapon. He told Korris that all that talk of glory and winning battles that he liked to spout was meaningless without a sense of honor and duty, and that Korris looked for battles in the wrong place. Worf told him that the true test of a warrior was not without, but within.
Angry that his attempt to turn Worf had failed he snarled that Worf was no Klingon while bringing his weapon to bear on Worf. Replying that perhaps he wasn't he shot Korris with his phaser. Korris fell through a glass panel to his death. Worf made sure to give Korris proper death rites, and reported to K'Nera that Korris had died well.
The following year Commander William Riker remembered Captain Korris while being treated for a parasitic infection he had gotten on the surface of Surata IV from a predatory vine.