Sable

This is the achievement you get when finishing the game.
After you've collected at least 5 masks you can go to a Postbox in a camp and get a message from Jadi that the Ibexi tribe has returned to Ewer.
Once you fast travel back there you go select the mask of the job you want to do for the rest of your life. PRESSURE!!! (Not really, you can still swap masks afterwords, it's just meaningful to the story.)

So basically this game was one big co-op/job shadowing simulator to find out what role you want to take on as an adult.