Content Warning: This section of the guide includes discussion of death.

Brown includes a map of the continent Helios on Mercury. The map was commissioned by Virginia au Augustus, Darrow’s wife, in the year 754 PCE (“Post Conquering Era,” referring to the Society’s takeover) during the Solar War (fought between the Solar Republic and what remained of the Society). The map depicts several key cities, including Heliopolis in the center of the continent, Tyche—loyal to the Core Golds (Golds of the “Core” planets—i.e., not the Rim)—to the north, and Polybos to the south.

A detailed dramatis personae is organized according to political divisions in the novel. Members of the Solar Republic include Darrow, Virginia, Pax, Kieran, Rhonna, Deanna, Sevro, Victra, Electra, Dancer, Kavax, Niobe, Daxo, Thraxa, Alexandar, Harnassus, Orion, Colloway, Glirastes, Holiday, Quicksilver, Publius, Theodora, Zan, Clown, Pebble, Min-Min, Screwface, Marbles, Tongueless, and Felix. The Solar Republic was formed after Darrow led a revolution to overthrow the Society. Critical members of the Society include Atalantia, Lysander, Atlas, Ajax, Kalindora, Julia, Scorpio, Cicero, Asmodeus, Rhone, Seneca, Magnus, Octavia, Aja, and Moira.

Under the Society, people were divided into a color-coded hierarchy: Golds (oppressive rulers), Silvers (innovators and businessmen), Whites (religious figures), Coppers (bureaucrats), Blues (navigators), Yellows (medical personnel), Greens (developers), Violets (artists), Oranges (mechanics), Grays (police force), Browns (servants), Obsidians (soldiers), Pinks (sexually trafficked persons and others used for pleasure), and Reds (laborers).