I have a basic understanding of what they fey are, but I'm not sure if that term just refers to the Fair Folk of Ireland, or is a general term for similar creatures from different mythologies like the Arabic djinn, Grecian daemons, Native American Little People, Shinto youkai, Nordic jötnar, and possibly elves. I'm under the impression the fey live on the astral plane, but the sheer volume of myths about them lead me to assume they can take physical form. I also wonder precisely what sort of society, way of life, and government they have. The Fair Folk were said to have kings, but so did humans when those tales were written.
Additionally, what is the "edge" of their territory? Does it extend beyond the Earth and, theoretically, reach to other planets or even universes? How does their civilization advance? Human society advances through economic growth and technological development, are the fey the same way? Do the fey spend all their time in astral form, or do they inhabit "worlds" on the astral plane that they travel between? Finally, what is their current relationship with humanity? We don't really see them any more, though some countries remain highly superstitious.