Camp Achlys
A small outpost in the Sapi-Res Nome area. You will come here during the Main Quest The Scarab's Lies, but since you'll be unarmed when you do, there are benefits to clearing it out a bit beforehand.
The lone treasure is in the central tent, practically out in the open.
The captain here is a dab hand with that bow, but you can use the ruined fort in the northwest to run rings around him- sneaking through the shrubs, hopping over walls and through windows, et al.
His death completes the location.
Camp Achlys does also have prisoners, who can be freed for additional XP.