A volatile raging sky reminds you of your anger and pushes 15 Tribes in their constant conflict.
A recursion of pitiless brutes, primal casters, war spies, mammoth hunters, poison tenders, and lore minders, lead by a Pinnacle Chief, the prime of each tribe. This is a primitive recursion in a perpetual cycle of war. Perhaps up to 1-2% of the population have the spark and are able to survive.
To leave a tribe is banishment. To join another tribe is death. No tribe will accept another tribesman as one of their own.
The 16th Tribe of Namoon, discovered or noticed by only those with the spark. It is the only tribe not in the cycle of war, independent, and seeking to understand the recursion they live in. The Namoon are members of other tribes that have awakened from the mundane to think for themselves. They are the ones that survived the journey to the Namoon forest. Namoon are mostly banished members from other tribes.