In the fourth season episode "Reunion", Duras was selected as a candidate to succeed K'mpec as Supreme Chancellor of the Klingon Empire. In order to assure his succession, Duras assassinated K'mpec by poisoning him over a period of six months, tainting his food and drink with Veridium Six toxin. As K'mpec had named Captain Jean-Luc Picard of the USS Enterprise-D his Arbiter of Succession, Duras was forced to endure a lengthy procedure to determine whether he or Gowron would assume leadership of the High Council. During the proceedings, Ambassador K'Ehleyr began investigating the circumstances behind Worf's discommendation and discovered Duras' involvement, learning that Duras was responsible for murdering K'mpec and that his house was and may still be in league with the Romulans. Duras confronted K'Ehleyr in her Enterprise quarters and murdered her, but this action invoked Worf's wrath, who claimed the right of vengeance against Duras. Worf and Duras fought aboard Duras' ship - the Vorn - and Worf defeated Duras by beating him to the deck and impaling him in the chest with a bat'leth sword.