Twilight Order—an organization created by the dying Chosen, in the last days of the Plague War, to give humans the ability to use deiat and sustain civilization after their extinction. Key to this purpose are the haken, Chosen arcana that allow the few humans capable of drawing on deiat to wield its power.

The purposes of the Twilight Order are to defend humanity as a whole, especially from plaguespawn and ghouls; to suppress knowledge of dhaka and destroy dhakim, as part of that defense; and to make sure the power of deiat is wielded for the common good. These themes are laid out in a book called the Inheritance, which details the history of the Chosen and the Plague War and explains the goals of the Order.

The core of the Order are the centarchs. Every human capable of wielding deiat that the Order is able to locate is brought to the Forge to become an agathios, a centarch trainee under an experienced teacher. When they are deemed ready by their master, usually by their early twenties, they receive their cognomen and are declared a full centarch. Apart from the Kyriliarchs, all centarchs are theoretically peers, and free to choose their own path, though in practice a great deal of deference is paid to seniority and unwritten tradition. Centarchs, wielding deiat through their haken, travel throughout the Dawn Republic and beyond, fighting plaguespawn and hunting dhak and dhakim.

The governing body of the Order is the Council of twelve Kyriliarchs. Generally senior centarchs, these members are nominated by the other centarchs, approved by the Council, and serve for life. Only a majority of the Council can issue directions that centarchs are bound by the laws of the Order to accept. The Council sets broad policy for the Order, directs centarchs to particular areas of trouble, and rules on intra-Order disputes and transgressions.

In addition to the centarchs, the Order includes supporting staff of several sorts. The Forge is maintained by hereditary families of servants, who do manual labor in the fortress. An extensive logistics service handles supplies and tracks the vast storehouse of arcana the Order maintains, and a courier service uses the Gates to provide rapid delivery of information. Arcanists help maintain equipment and work with centarchs in the field to research arcana. Another group, called scouts, supports the centarchs directly on missions and maintains outposts and intelligence-gathering operations throughout the Republic and the Splinter Kingdoms, working undercover where the Order is not welcome.