These stories are a smutty mixture of fantasy and early industrial age technology… a gaslamp fantasy in the redlight district, if you will. The realm is a filthy, bloody, war-torn place where Man and Fae have warred for centuries, both sides are pushed to the brink.
Elves
Elves are lithe, graceful creatures with long pointed ears. Contrary to legend, they are not immortal but instead will live until violence, starvation, or disease takes their life. Elves grow to maturity in twenty years, after which aging slows considerably until at least five hundred years. Most peasant class die from their meager existence before they hit the century mark.
Their long lifespan is balanced by a terribly poor birthrate. Their population is easily half of the disparate human kingdoms, a fact that does not sit well with the empress of Fae-kind.
Most Elves are magically adept, particularly amongst nobility. Magics are woven into daily life such that weaving spells is as common as smithing a horseshoe.
Imaren Empire
Elves have many cultures but all serve the Imaren Empire, ruled by the ancient and beautiful Empress Milaen. The empire has existed for millennia under her rule, dominating most of the world save for a few scattered clans of unaffiliated Fae or tenacious Humans. From the Faeish perspective, the empire is benevolent and refined. Most technological and magical advancements were borne of Elven ingenuity, after all.
The Imaren Empire declared sovereignty over all the lands and peoples. As centuries churned by, most kingdoms of Fae-kind bowed to the inexorable expansion of the empire. Only the strongest of Human kingdoms survive, waging a never-ending war to keep the empire at bay.
These wars have lasted for over a thousand years and have taken a toll on Elven population. The Empress had foresight long ago to ensure the survival of her people. Milaen made secret pacts with powerful, forgotten deities that have questionable motives. These entities answered Milaen's plea with their own capricious twist, infusing the Elven people with a magical state known as the ly'rinn.
The Ly'rinn
The ly'rinn is a mysterious and unpredictable magical force that affects Elven women, filling them with an overwhelming, insatiable desire to mate. It can strike at any time without warning. The intensity of the ly'rinn is such that resisting it is nearly impossible, and most women succumb within moments.
Men are not affected by the ly'rinn, but they are often "caught in the crossfire," as it is considered cruel to deny a woman in such a state. It is quite difficult to satisfy a woman under the influence of the ly'rinn, however, and men often get more than they bargained for.
The Caorann
A caorann is a troupe of women who support one another through the effects of the ly'rinn. While this provides a safe outlet for the insatiable desires inflicted by the magics, it is often seen as low-class or a pitiable state of affairs.
The ly'rinn does not discriminate, however, so both noble and peasant can be found in the ranks of a caorann. If a noble is found incapable of performing her duties due to the ly'rinn, there is a good chance she will be stripped of her title and forced to join.
Mandratha
In bygone days before the warring, Mandratha stood as a proud cultural epicenter of Fae-kind. The gilded white marble of this ancient city lies buried beneath ramshackle sprawls and industrial slums.
There is stark disparity between classes. The elite exist in comfort while those outside a place of station exist in destitution and squalor. Imperial law is the singular equalizer, however, that neither class can ignore.
Mandratha, once a place of peace and wonder, is now home to intrigue, conspiracy, and the struggle to survive. It is the stage where these sordid tales take place.
TLDR
Elves: I like them.
Imaren Empire: Empire of Elves, hates Humies
Ly'rinn: Magic force makes girl horny (also lame excuse to write smut)
Caorann: Horny girl club
Mandratha: Hive of scum and villainy, also an homage (your Google ain't broken)