Duras, son of Ja'rod, and leader of the House of Duras, was a powerful and ambitious political figure in the Klingon Empire during the late 24th century. He and his family would become notorious for dishonorable and sometimes treasonous tactics in order to accumulate and maintain power, which would culminate in the Klingon Civil War of 2367-2368.
On the High Council
Duras was a member of the Klingon High Council in 2366, when he led the capture of a Romulan vessel. On board the vessel, records were discovered implicating Duras' father as having betrayed the Khitomer colony to the Romulan Star Empire by giving them the codes to lower the colony's deflector shields. In the resulting Khitomer Massacre, 4000 Klingons, including Ja'rod, were slaughtered.
Unwilling to have his position threatened by being labeled the son of a traitor, Duras convinced Chancellor K'mpec and the rest of the High Council to shift the blame to Mogh, leader of the Duras family's long-standing enemies, the House of Mogh, and who had also been killed in the Romulan attack. Concerned that accusing the powerful Duras family of treason could lead to unrest or even civil war, they agreed.
None expected Worf, the son of Mogh, and a Starfleet officer, to come to Qo'nos to challenge the accusations against his father. Fearful that Worf might learn the truth, Duras ordered assassination attempts on Worf's Cha'DIch; first on Kurn (who, unknown to the High Council at the time, was Worf's brother and also the son of Mogh), then on Worf's commanding officer Jean-Luc Picard, who took over after Kurn was injured.
Nevertheless, Picard managed to locate Kahlest, a woman who had served the House of Mogh as Worf's nursemaid at Khitomer. Her eyewitness account of the attack corroborated Worf's assertion that his father was innocent, though K'mpec refused to allow her to testify before the council for the same reasons they had shifted the blame to Mogh to begin with. Worf recognized the necessity of preserving the stability of the Empire and accepted discommendation, though not before striking Duras and vowing the the truth would one day come out. (TNG: "Sins of the Father")
Vying for Chancellorship
The following year, K'mpec was revealed to be dying of a cumulative poison called Veridium Six which had been slipped into his bloodwine over several months. By Klingon custom, this was a highly dishonorable act because the killer did not show his face. It was suspected, but never proven, that Duras was responsible. With K'mpec's death imminent, Duras quickly emerged as one of two contenders to become the new Chancellor. The other was Gowron, a political outsider.
Hoping to prevent a dishonorable man from attaining chancellorship, K'mpec, in one of his final acts, appointed Picard as Arbiter of Succession. Duras came aboard Picard's ship, the USS Enterprise-D, from the IKS Vorn to compete in the Rite of Succession, as did Gowron from the IKS Buruk.
The Rite of Succession began with the Sonchi ceremony aboard K'mpec's ship. Picard, as Arbiter, and the two contenders prodded K'mpec's lifeless body with Klingon pain sticks to officially confirm the death of the old Chancellor. Duras appeared to be disturbingly enthusiastic in doing so. Moments after the completion of the ceremony, however, a explosion rocked the room, killing a member of Duras' entourage, and one of Gowron's as well. The bomb was found to use a molecular decay detonator, a device well-known to be of Romulan origin, with the obvious implication that one of the contenders was collaborating with the Romulans.
Hoping to buy time to find out who was responsible for the bomb before the new Chancellor was selected, Picard chose to revive the ancient Ja'chuq ceremony, in which each contender lists the battles they've won and the prizes they've taken, to demonstrate their worthiness to lead the Empire. The ceremony was expected to take days.
Before it was complete, however, Duras discovered that Ambassador K'Ehleyr was investigating the events at Khitomer to find out why Worf had apparently dropped his defense of his father and accepted discommendation so easily. When Duras confronted her, K'Ehleyr demanded to know what had really happened at Khitomer. Duras fatally wounded the Ambassador and returned to his ship.
While Enterprise-D personnel uncovered evidence that Duras' people had been responsible for the bomb, Worf discovered K'Ehleyr dying. With her final breath, she identified Duras as her killer.
Worf immediately beamed aboard the Vorn, telling Duras that K'Ehleyr had been his mate, and challenging Duras under Klingon law. Duras smugly told Worf that if he killed Duras, no one would ever learn the truth about his father and Worf would be labeled a traitor forever, but Worf was unswayed. Duras, more politician than warrior, was no match for Worf and was quickly killed, impaled on Worf's bat'leth. While the Klingon Empire regarded it as a lawful killing and considered the matter closed, Worf was reprimanded by Captain Picard. With the death of Duras, Gowron was apparently unopposed to become the new Chancellor.
Though Duras was dead, his family's ambition would continue to threaten the Empire later that year when his sisters Lursa and B'Etor revealed that Duras had had an illegitimate son, Toral. Toral became head of the House of Duras in name, although the real power remained with Lursa and B'Etor. The Duras family challenged Gowron's claim, and the ensuing power struggle led to the Klingon Civil War. Initially, the Duras forces appeared to have the upper hand, as they had continued the family tradition of allying themselves with the Romulans. Once a Starfleet blockade prevented any further Romulan supply ships from reaching the Duras, however, the tide quickly turned in Gowron's favor and the Civil War came to and end. (TNG: "Redemption, Part I & Part II")
Efforts in recent years by Lursa, B'Etor, and Toral to rebuild their forces and reestablish their family's standing within the Empire has met with only limited success. It is unlikely the House of Duras will ever reattain the power it wielded during Duras' lifetime. (DS9: "Past Prologue"; TNG: "Firstborn"; Star Trek: Generations; DS9: "The Sword of Kahless")