Games, all sorts

The planar boundaries between Farne and the multiverse are thin. It has long been a battlefield in the Blood War¹⁾. Angels and Demons walk the surface with surprising frequency. Similarly, there are several places where the elemental planes themselves burst through the walls of reality and snake veins of the fundamental forces of reality through the landscape.

The races of the world were mostly ignorant of the goings on in their midst. Seeking to protect their world from becoming a war torn battlefield, 10 arch-elementals planted the seed of magical knowledge in the fertile soil, tended it with great care, and then withdrew once it had germinated.

The seed grew quickly in the fertile soil. Thirty-five years later, the time from the first incantation to the opening of the planes to the inhabitants, the veil was thrown aside as the Arcanis Rift²⁾ formed. This exalted numerous lesser beings to divinity, finally providing the moons company in their lonely orbits.

Nearly 4500 years later, the blood of demons, angels, gods and elementals mingle through the races. The majority of the time, these traces are too faint to do anything. On occasion, however, the powerful blood is concentrated enough to transform the scion into something more than he or she was originally.

The spark of magic flows brightly enough in to enable roughly 1% of the population to use basic hedge magic and summonings. Simple tricks to keep the demons at bay or woo the affections of a sweetheart. They often will become village healers or the crazy man down the street. Perhaps 0.1% of the population is (un)fortunate enough to burn brightly enough to wield true power.

This 0.1% is highly coveted. In less law-abiding nations, individuals that burn brightly but aren't part of the government will be kidnapped or pressed into military service. Slightly less disturbing are the breeding programs that have developed in places like Upper Thalia and Masayume to concentrate the spark in loveless marriages.

The 0.1% are able to blow softly on the latent embers in their veins, uniting their august heritage (angel, demon, god, or elemental, or some of each of the above) with their human blood to become something more. This divine spark (lets call it eminence!) can grow, allowing the (hey, lets call them the manifest) to become greater than the sum of their parts.

With the lower case 'g', the deities of Farne aren't all powerful. With a few exceptions (Seracoth and Kestia spring to mind), the Farnian deities are normal people that managed to become deities. As such, they can and do continue to have normal interactions with humans. This will occasionally result in a child being born.

Angels and Demons are the same thing, though one is dominated by vice and one by virtue, and can quite easily have children with mortals. See this apocryphal tale for an example.

Whether they're Jinn, Sylphs, Dryads or Ifrit, the world is filled with elemental beings that can pass as exotic humans if they want. Further, some actively seek out the comely and beatific. Regardless, children with the blood of the elements in their veins are far from unheard of.