The Decline

The Decline is an extremely powerful curse that affected every living elf (at least all of the ones not in suspended animation) and it is passed down to their children. The Curse of the Decline - also called Lasku by the elves - is believed to have been enacted 1213 years ago, and is thought to also be related to the birth/creation of the four elemental dragons. Elven scholars have been researching ways to counteract the curse since elvendom realized what had affected them, some 1150 years ago. Up to this point, their research has been fruitless - the curse seems to have been created by a binding power verging on the deific level. Most such curses cast by even the most powerful groups of mortal mages would have lost strength after three generations, and would have at most, been able to impact a continent, rather than the global impact that the Curse of the Decline achieved.

Effects
The Curse of the Decline massively reduced the already low fertility of the elven people, and seems to have made some sort of physical and spiritual impact to elves that the Fey are quite sensitive to. They fey, once quite friendly with the elven people, now treat elves with suspicion and disdain.

While elves once enjoyed a fertility rate of 2.2 children per woman over the woman's lifetime (typically 400-600 years), that has dropped precipitously to a mere 0.25 children per woman.

The scarcity of children has had a tremendous impact on elven culture. Elves, once renown for bravery and cheer, have become reticent and somber. As the numbers of elves dwindle, they continue to pull back into their largest cities and strongholds. Where a thousand years ago, elven settlements and cities were numerous on every continent except Hauner, elves are now almost completely unseen outside their native continent, Kotime.

Link to Elemental Dragons
''Very recently, the green earth elemental dragon, Vossaprus, and his lair were destroyed as a result of a combined effort between Elves, Fey and a handful of creatures called Humans. In the short months since then, elves have seen a small but notable improvement in conception rates across all of elvendom. Tentative estimates indicate an improvement to roughly 0.5 children per woman over her lifetime.''

System Notes
Many of the effects are intangible, but a few of them do manifest numerically.

Essence Loss
Each elf under the effects of the Decline suffers a -1 penalty to their Essence. This impacts their ability to cast magic, attempts to resist death, and certain social situations with creatures of Nature.

Low Fertility
No need for math here. Elf PCs do not reproduce unless the player and DM are interested in pursuing that story route.

Nature's Scorn
Creatures of nature are particularly sensitive to the Elves' decline. When an elf is dealing with undomesticated animals, fey, avatars of nature, and native elementals, multiply the elf's total Essence loss by 2 and subtract it from the elf's Social Limit for that situation.

Example:
Hypellä, a former pirate captain, lost her right foot to a sea monster years ago, and replaced it with a magically-grafted silver boot. She had lost 1 point of essence from the curse of Decline, and another half point of essence for magically grafting a replacement appendage, for a total loss of 1.5 Essence. Her Essence stat is now set at 4.5, and if she is a spellcaster, her Magic stat is impacted by this essence loss. Normally, Hypellä's social limit is 7, buy when she's trying to negotiate with fey, she suffers a (1.5x2) 3 point penalty, dropping her social limit to 4. She'll have to be careful, because just about anything she says could accidentally cause offense!