the bandit boss in the first quest can be found in a campsite near town. It will appear as a tent on the overmap when you get close enough to it that your party leader can see it. There are multiple of these campsites near town. Each one has a chance of having bandits in them. If you encounter bandits at a campsite the battle is guaranteed to have the bandit boss if the quest is active.
Viewing post in Mission help section (spoilers)
Suspended account310 days ago
Show post...
found only 1 camp and each time i checked it, it said there was nothin
Suspended account305 days ago
Show post...
finaly found another tent, north east, damn thing really need you to hug the square where it is to be visible