Within the Wilderness, ferocious beasts are hard to hunt, and their blood is precious - one of the finest ingredients for body tempering.
Moreover, the stronger and more precious the beast's bloodline, the better the effect of its blood in body tempering.
According to a friend of his living in a village, all boys reaching a certain age must undergo a medicine bath in his place. The blood of the ferocious beast, combined with several specific herbs, could yield enhancements in strength after soaking for a certain period of time.
Thus, they have developed into their current state, survived in the perpetually dangerous Wilderness, and passed on their lineage.
Old man Lin once tried to inquire about the recipe but was categorically denied by the other party.
Each ancient body-tempering formula is a long-standing tradition and one of the core treasures of the village, hardly ever revealed to the outside.