Mark was a captain and a soldier of Regal. He had made a deal with Nik Holdfast about giving gold and safe passage to Nik's group of smugglers and pilgrims in exchange of them giving Fitz over to him. This wasn't the first deal he had made with smugglers. His own men were dissatisfied that they never profited from these deals. He drowned during the attack the soldiers made on the travellers while they were crossing the Cold River.