Deciding whether you should kill the soldiers at Mert's Mill during Blood of Dawnwalker's The Firebrand quest looks like a minor choice at first, but a life does hang on it. After investigating Vlad's house in Laslea, you'll be directed to the mill in the region to the south. When you arrive, though, you'll be confronted by a bunch of soldiers, and you'll have to decide what to do about them.
