The Regent of Palamar
The Regent of Palamar was an extremely wealthy ruler of an interstellar empire. In 2373, he was betrayed by his subordinate General Nassuc, who he had originally planned to inherit his army. Infuriated, the regent met with arms dealers Hagath and Gaila, and their recent employee Quark, aboard Deep Space 9 to purchase biogenic weapons. He intended to make an example of the insurgents by eliminating twenty million people on Nassuc's homeworld, starting with the eight million in her capital.
However, Quark was appalled by the regent's plans, and so he surreptitiously invited General Nassuc to the station and led them to the same cargo bay as where the regent was due to view a weapons sample. A firefight broke out when the two sides saw each other, and the regent escaped from the station, only to be killed by a purification squad of Nassuc's Palamarian Freedom Brigade a day later. (DS9: "Business as Usual")