The Society's rigid caste system dividing humanity into ranked Colors, each marked by Sigils and bred to a role.
The Colors are the castes of the Society, a pyramid of humanity in which each person is born, marked, and bound to a Color and its role. At the apex are the golden Golds (Aureate) who rule; below them serve the giant Obsidians as soldiers, the Grays as police and troops, the Coppers (Pennies) as bureaucrats, Oranges as technicians, Yellows as doctors, Pinks as pleasure-servants, and at the very bottom the Reds, who dig. Each Color wears its Sigil branded into the skin.
The system is enforced as natural and eternal, its lowest members taught that their toil is sacred sacrifice.
Each Color distinguished by hair, eyes, and a distinct skin-Sigil; Reds bear a circle with an arrow and cross-hatching, Golds a winged circle with a central dot.
The caste framework organizing all of the Society's humanity into ranked, Sigil-marked Colors.