The Firstborn are creatures of the primordial Mists that sprang fully formed into being.
The firstborn claim that they ruled and even created the entire world and that they alone had the right to dictate the laws and decrees of the magical realms. Though skeptical, many Fae agreed to this and referred to them as the "True Fae". The firstborn are truly the embodiment of the horrifying or astonishing in their appearance. They range from creatures of the darkest and most perverse nightmares to the gentlest or most glamorous of angels.
The rise of humanity strongly diminished the power of the Firstborn and many feared their potential. In the cause of the Shattering, most Firstborn were trapped in Arcadia and cannot reach the mortal realm due to the strong Banality that works there.