Society in the Realm is broken up into five broad castes. From the top down, they are:

The Heirs of the Scarlet Dynasty (aka Dynasts)

The dragonblooded, who rule society within the Realm. Only they may own land or slaves.

The Patricians

The unExalted members of the Dynast families, as well as merchants, bureaucrats, and military officers. They lease land from the Dynasts (in the form of profit shares from the land's use).

The Serfs

The vast majority of mortals in the Realm. They have few rights, and rarely interact with the Dynasts, seeing them as semi-divine.

Slaves

Most slaves are foreign born, but some are former serfs that violated the wrong law. Only Dynasts may own slaves, but they often rent out slave labor to the patricians.

The Disenfranchised

Former serfs (and rarely patricians) who have been ejected from Realm society, and stripped of all rights. They generally try to flee the Realm for the Threshold as soon as they are able.