An exarch is a title of an official used by the Cardassians and the Rakhari.
In the early 2360s, Kotan Pa'Dar was exarch of a Cardassian settlement on Bajor during the Occupation. (DS9: "Cardassians")
Hadran was exarch of Rakhar's Nehelik Province in 2369. (DS9: "Vortex")