Caveat: This is very loosely based on what Mississippian culture may have been like, with many interpretations taken solely for the purposes of playability.
The Children of the Sun have a belief in both an Overworld and Underworld (which tie in nicely for game purposes with Law and Chaos). While farming is critical to their society, most adventurers will come from either hunters or the priestly caste, devoted to either the solar (Empyreal) or underwater (Chthonic) deities. While the solar deities are loved and are the primary focus of worship, the power and danger of the underwater deities are respected. Some Children devote themselves to understanding and appeasing these Chaotic powers, while others see them as a path to power.
Special quality: weapon restrictions: classes taken by Children of the Sun must have either Restricted or Narrow weapon selection. If Narrow, they are proficient with six weapons: Battle Axe, Dagger, Javelin, Longbow, Mace, and Sling. If Restricted, they are proficient with Dagger, Dart, and Sling.
Child 0 (550 XP) - Hit Die 1, Blade-Dancing
Even the least of the Children are reasonably hardy, and play physical sports that teach them to evade blows.
Child 1 (825 XP) - Cleric 1, Aura of Protection (against chaos if devoted to the Solar, law if Underwater)
The lowest of the upper class, these Children learn the basic rituals for communing with their gods, and are very slightly gods-touched, protecting them from creatures devoted to the opposing half of the pantheon.
Child 2 (1375 XP) - Hit Dice 2, Holy Fervor
Typically a warrior dedicated to one of the cults of the Children’s culture, this group is able to inspire those who fight alongside them, and are known for their resilience in combat.
Child 3 (1475 XP) - Hardy People
Still part of the “Child 2” grouping, this represents a character who has received more survival training, and is better able to survive non-combat difficulties in addition to their combat training.
Child 4 (1750 XP) - Cleric 2, Heroic Spirit, Divine Health
The high priests and rulers of the Children, these society members are the most closely connected to their deities, making them immune to some mundane concerns and giving them more potential than other Children.