Belkas was born and raised in a tiny, remote community. The community was largely isolated from any significant contact with the rest of the world and as a result everyone was expected to make a contribution.
Belkas learned about hunting and trapping from a young age and how to live off the land. He also needed to learn how to defend himself from wild animals as well as help in fending off the rare bandits.
As he grew into adulthood Belkas grew curious about the world away from his home and eventually set out to explore. Despite the value of his skills learned through childhood he quickly came to realize that exploring the world all by himself was a difficult endeavor. So upon learning of the Pathfinder Society he joined up, confident that it would be an excellent way to continue his adventures.