Vagh was the Klingon governor of Krios in 2367.
That same year, Romulan Commander Sela ordered the abduction of Lieutenant Commander Geordi La Forge and used a brainwashing technique to instruct him to murder Vagh, and thus draw the Federation into conflict with the Klingons. However, the plan was thwarted, and further Romulan/Klingon cooperation uncovered. (TNG: "The Mind's Eye")