The Stray Folks used to be orphans who were raised in a monastery from a secluded village. They grew up on their own and quickly learned to use each other’s strengths to face adversity. As teenagers, their bonds grew even stronger, and the most valuable lesson they learnt, which is to keep each other's back at all times, saved them from a threat they had never encountered before.
On a sunny summer day, their village was raided and burnt to the ground by savage tribesmen. The knowledge of the surrounding woods and survival skills allowed the teenagers to escape the horror. Not all of them were unharmed, but all could run to leave the place forever, and so they did.
They have been travelling and adventuring ever since, under the name of the Stray Folks. These are bunch of not-so-badly-intended guys, but they've learned how to survive by any means.