The Dragon Empire
When the great human empire began to decline due to overreach and internal power struggles, it was divided into separate Eastern, Western, and Southern empires, symbolized by a dragon, lion, and goat, respectively (from the Chimera that symbolized the original Empire). During the War of the Rifts, as the West and South fell into ruin, a new emperor took control of the Eastern empire. Claiming to be the embodiment of Bahamut, and worshiped as a demigod, he can assume the form of a man or a gold dragon. He is referred to only as the Dragon Emperor (and other honorific titles) by his subjects.
The Dragon Empire is dominated by Easternese humans, who are culturally, architecturally, and stylistically similar to the peoples of East Asia in feudal times (or at least as it depicted in pseudo-historic fantasy, anime, & kung-fu films). Easternese is the official language of the empire, though Draconic is used for religious and ceremonial purposes. Dragonborn, who always held a special place in the Eastern Empire’s elite troops and Imperial Cult, came to dominate (in importance if not in numbers) the upper ranks of the military, civic religion, and state administration.
The empire has a well-developed civil service and bureaucracy for collecting taxes, maintaining public works, administering justice, and other functions. Provincial governers and other important officials are appointed by the Emperor. The Imperial legions are the largest professional military force in Arekhan, and have been used more than once to quiet dissent in restless provinces.
Imperial Dragon Cult
In previous human empires and certain other cultures, the emperor and his family spirit are worshiped alongside the gods. In the Dragon Empire, this has come to dominate the religious landscape. Every city & town has a civic temple, dedicated to all the major gods, but prominently featuring Bahamut and his incarnation, the Emperor (much as most temples of the Church in the West will prominently feature Pelor as first among equals). A wide variety of lesser temples and shrines dedicated to various gods and spirits can be found throughout the Empire, just as they are in the West and elsewhere.