The Color-caste empire spanning Mercury to Pluto, ruled by Golds atop an engineered hierarchy.
The Society is the sprawling empire that rules humanity from Mercury to Pluto through a rigid, genetically engineered caste of Colors—Golds ruling; Obsidians as warriors; Grays as soldiers; Blues crewing ships; Coppers as bureaucrats; Oranges as technicians; Violets in media and craft; Pinks as courtesans; Reds and Browns toiling at the bottom. Its logic is that to prosper, one's superior must prosper, breeding a loyalty of necessity that patronage—like Darrow's under Nero au Augustus—reinforces. Its maxims are absolute: only the strong survive, only the brilliant rule.
Peerless Scarred Golds are shielded by the Compact, enforced by the Olympic Knights. It is the machine Darrow and the Sons of Ares mean to bring down.
The ruling order of the worlds; the vast Color hierarchy Darrow seeks to destroy.
Also appears in books you've already read — spoiler-safe to their endings: