Borath

Borath was a Vorta who oversaw an experiment that placed the crew of the USS in a simulated reality. The goal was to gauge how the Federation and Starfleet would react to Dominion inroads into the Alpha Quadrant. During the simulation he posed as the Dominion representative to the Federation. 

In 2375, Borath oversaw a simulation that was run on Lieutenant Terri Letac, which was run on a warship. During the rescue of Letac by Special Operations Command that particular clone of Borath was killed. (: "Always on My Mind")