Blood & Iron: The Warcaster Chronicles, Book 3

Warcaster. Mutineer. Pirate. Captain Phinneus Shae is a man of many titles - all of them could get him killed. Returning from the remote continent of Zu, the crew of the Talion is stricken by a mysterious plague. When Captain Shae goes ashore on a small island to find medicinal plants to treat his men, Mercarian League mercenaries ambush him, and their ships, fast and deadly pirate hunters, close in on the Talion. In a desperate bid to outrun or outgun the Mercarian vessels, the Talion takes to open waters. But Shae's pursuers know him well - one of their captains served with him when Shae worked for the Mercarian League and can anticipate Shae's every move. And the pirate hunters may be the least of Shae's worries: an infamous assassin, the sniper known only as the Ghostmaker, has been contracted to kill Shae and collect old debts of Blood & Iron.