Dragonborn

In the arid deserts of the west, a grand civilisation runs along the Great River. Golden pyramids, obsidian obelisks, and grand temples all glisten in the sunlight. The grandios cities all prosper greatly from the rich soils that run along the river. The current dwellers of these lands are the dragonborn, cold blooded reptilian humanoids in their element in the scorching heat of the desert.
Dragonborns are immensely tall, reaching up to seven foot. They are covered in hard scales of varying colours and have long, thick, powerful tails. Their face shape resembles that of a dragon, including a set of powerful fangs more than capable of tearing flesh from bone. As they are also the descendants of dragons, all dragonborn possess the innate ability to breathe a particular substance depending on their ancestors colour, i.e. red dragonborn can breathe fire.
Due to their cold blood, dragonborn prefer to stay in warmer climates. It is almost unseen to see dragonborn in the colder regions of the north as their metabolism slows down too much and they fall into a coma like state to prevent themselves from dying. It is due to this that the only dragonborn settlements in Ereth are along the Great River in the Endless Sands desert, with a few scattered communities in the Scorching Canyons.
Dragonborn society is very different to other races. Much of their life is based upon their religion; the Ten. The ten dragon lords, represent every aspect of their life; their colours, their abilities and even their social standing. Chromatic coloured dragonborns are usually the soldiers, builders, and crafters of their society. The metallic coloured ones are leaders, scholars, mages, and healers. As dragonborn give their life to their society, much the same as a bee would for their hive, dragonborn don't have the same level of individualism as other races. You are assigned your place at birth based on the colour of your scales. An interesting point is that their colour is not a genetic thing but rather divine. A blue and black dragonborn couple could hatch a red dragonborn for instance.
Most dragonborn accept this way of life as it is considered an honour to contribute to the growth of their civilisation however mundane their task. There have been exceptions throughout history though of course. A few dragonborn get an itch for adventure, for leaving their mark upon the world. And so they leave their society to forge their own path. This is not a decision made lightly though, as to forsake your role in dragonborn society is to exile yourself, never to return.
Dragonborns don't have a king or queen in the traditional sense but rather follow a group called the Matriarchs. Five female dragonborn of the metallic varieties oversee all within their realms. When one matriarch dies, the other four will deliberate and choose a new one. In the event all five are killed, the metallic dragonborn vote for their corresponding colours matriarch. Becoming a matriarch is a lifelong commitment, once you are in you are there till death. Another interesting note is the stereotypical gender roles found in humans are actually reversed in dragonborn society. Female dragonborn are larger and stronger than males and the females will usually take on the roles of soldiers, farmers, and crafters.