Karnas was the Governor of Mordan IV, who staged a hostage crisis to lure Admiral Mark Jameson back and avenge decades of civil war.
Karnas was the Governor of Mordan IV in Too Short a Season. He contacted Starfleet saying terrorists had taken a Federation ambassador hostage and asked for Admiral Mark Jameson, who had negotiated a hostage settlement on the planet decades earlier.
The truth emerged that Jameson had secretly armed both sides in that earlier crisis, plunging Mordan IV into a long civil war, and that Karnas himself had staged the new hostage taking to get revenge. Jameson, rejuvenated by an alien drug, tried to set things right but died from its effects, and Karnas then gave up his vendetta. Michael Pataki played him.