Heroes of the New Day
Stark raving mad, fomorians also act as the civilizing force of the Feydark. What dim points of light exist in that benighted realm likely came from their initiative — and the work of their cyclops followers, who worship the fomorians as gods. Twisted reflections of titans that forged the world, fomorians are driven mad by strange double visions.
Their normal eye and evil eye constantly conflict, with one showing the world as it is, the other as it could be—entirely under their rule. Only when the two visions match is a fomorian satisfied, but they never do. Nevertheless, fomorians work tirelessly to bring the Feywild under their dominion. Though their dreams of conquest are often stymied by eladrin forces on the surface, fomorian forces delve deep, assaulting the deadly wilds of the Feydark and imposing their laws and decrees upon the creatures within it.
In recent centuries, the war against the rest of the feywild has ramped up, with Fomorians now having large settlements on the surface of the Feywild. This is likely due to the decrease in the power of the eladrin, or possibly might be related to the Great Cataclysm, or maybe there’s some all-powerful force that finally organized all the Fomorians into a more effective battle unit (seems like the sort of thing Bane or Gruumsh might attempt). Also, they’ve started attracting other fey creatures to their banner (usually by torturing them into insanity, but that’s a pretty standard recruiting tactic, isn’t it?).
These days, many of the Archfey have their hands full keeping the Fomorian forces at bay. Some Fomorians have even taken to hiring assassins to try and remove various Archfey from existence. The fact that 99.9% of folks in the Prime Material plane have no idea this war is going on speaks to something… either the ignorance of mortals, or the vastness of the Feywild, or the power of the Archfey, or maybe the strength of Vecna’s forgetfulness powers.