Alsara: Requiem and Revolution
This man is a merchant of Atur; not a Merchant Lord, just a man that works with money. Unlike most merchants, however, Baki Ozan has access to two terrifying things: first, he has a ship, called the Starling, which has been outfitted as a Vokayan Keravnos, one of the elite hit-and-run ships used to kill high-value naval targets. Two: he has a powerful Vokayan mage named, or at least called, the Lady, and she answers to his orders without question.
He was encountered in the city of Mudberg on the northern border of the Dunvales Conclave, trying to set sail further east, up the Reisig. He was successful, with the help of the protagonists. Where he is now is anyone’s guess, but with the speed of his ship, he likely is already upon the Great River.