At some stage in the game, you will meet a good looking guy called Nil. This will trigger a sidequest for a bandit camp. You will likely have already completed one as part of the games main quest lines. There is a camp full of bandits and you need to kill them all. Not too complicated really. These turn out to be fun for one main reason. Humans have heads that are fun to shoot with arrows.
There is no major secrets to know. Kill all of the enemies in each camp to clear it. Set free any slaves that are caged up and they will fight with you to clear the remaining enemies and that’s about it.
You will spot bandit camps on the map by the blue skull with 2 sticks over the top of it.