The Dragonborn can thank their existence to the Draconic Empire’s system of nobility. Underneath the Collegia, a system of mortal nobility arose in order to act as caretakers of the kingdom. The group that was selected for this important duty were the early members of the Knights of the Talon. These houses were given special authority to make local laws as needed. These nobility eventually grew seperate from the Knights and collectively became known as the Congress of Houses. To show their favor, Dragons would often take members of the Congress as lovers. The resulting progeny were half-dragons. These half-dragons were typically given more authority than other mortal members. As a result, Houses soon began to consolidate into Houses with half-dragon members. Half-Dragons soon began to swell the ranks of the Knights of the Talon and within 200 years, they comprised the bulk of the order. These half-dragons typically took human spouses and after 300-400 years, their progeny were simply given the title: Dragonborn. They were not half-dragon and not human, they were somewhere in between. Because of their heritage, dragonborn were given privileged status and were not subject to the mortal tax (a tax paid on the estate of a deceased citizen).
With so many different types of dragon flowing through their blood, they soon discovered that nurture could dictate their nature. At the age of puberty, Dragonborn must choose the nature they wish to be able to channel. At a ceremony held in their local temple to Dimarra, the young dragonborn are exposed to a particular element which they will forever be able to channel through their breath.