A quartermaster provides clothing, food, and equipment for the soldiers. Geralt will often find him standing beside an anvil and a grindstone, showing that he is currently working on the soldiers' weapons as he is a blacksmith.
When Geralt first talks to him, he accuses him of spying, showing that he does not trust him. He does so again if Geralt asks about camp morale, and adds that their victory is assured and nothing more. However, this may only be a warning since he is keen to trade and do blacksmith work.
† He will only sell these after the prologue is finished and Geralt returns to the area.