Emanuel Zoak is a Mercenary Captain in name, but in practice he's really more of an admiral. Having assembled a fleet of bought, stolen, confiscated and salvaged vessels, Zoak was the leader of the only decisive naval battle in Dacian history, destroying Pishka's fleet and allowing the landing of troops on the coast, cutting off supply lines to Vedrim's largest enemy, and effectively forcing her surrender.
Though Zoak's contributions to the war were great, he was in no position afterwards to actually capitalize off of his power, as his fleet was in shambles and unpaid. He was made a Great Captain, and uses this authority to organize fleets to protect Dacian trade in the Tattered Sea, but can do little else.
Zoak's real weapon is his political acumen. He alone of the Great Captains represents himself in the senate, and has nearly convinced them to fund his efforts to establish a professional navy for the country to replace its aging and undermanned force.