The world consists of three known planes - Arundel, the land of the normal, Feywild, the land of the fantastical, and Shadowfell, the land of shadow.
Feywild, Shadowfell, the Underdark and Melora's Sea:
The Feywild is a sprawling land, a magical and strangely beautiful copy of Arundel. Passages between the Feywild and Arundel used to be prevalent, but many millennia ago the two were separated. Now only six major portals exist between the two planes; as a result the only creatures in the Feywild ` the native species: the Eladrin and the Faeries.
Shadowfell is studied intensely in the Feywild, but the only known method to get there involves first going through Arundel, a task attempted by few. As a result, the majority of knowledge of the Shadow Lands comes from books; it is believed to be inhabited by the "Dark Folk", tall, thin, darkly twisted humans, and a mysterious race known only as the Ghostwise.
The Underdark is a series of underground caverns and passages that is known to exist in all three planes; in Feywild, it is called the "Feydark", and is primarily full of glowing mushrooms, and the occasional Faerie community.
The Goddess Melora is known to have her own plane, accessible only through the Feywild. It is believed to be beyond the Infinite Ocean, but none have been known to go there and return alive.
Arundel is inhabited by Humans and Elves as well as various other strange species. Inhabitants of Arundel are mundane when compared to the inhabitants of the Feywild and most Fey initially find them extraordinarily uninteresting.
The countries of Arundel imitate those of Feywild, though it has many more cities and fewer forests.
The Feywild was rocked by the Drow Wars a generation ago when Dark Elves spread from Arundel's Underdark and found an entrance into the Feywild. Creatures of the Feywild used their superior skill and accuracy to fight them off and when they kept coming through the interplane passage the Fey Army went through to Arundel, fighting alongside the mundane until the dark creatures were defeated.
To help the Fey Army Melora herself contributed a number of Holy artifacts: a Crest, a Sword, a Shield, a Bow, a Helm and a Chalice. Once the war was over these artifacts were distributed between the schools that provided the mightiest warriors to the battles, and to this day they are held in positions of highest regard and honour.
Feywild has numerous ambassadors with the Elfs of Arundel, but very little contact with the other mundane races. The average Eladrin will only ever encounter other Eladrin in their long lifespans though a lucky few will see (or even interact with) Faeries.
While there are no official guidelines on travelling to Shadowfell or Arundel, it's rare for an Eladrin to desire this without a particularly compelling reason.
An official map has never been drawn of the Feywild and so most Eladrin know only their home area and surrounding cities and towns.
The six passages between the Feywild and Arundel are each named, and the general location of each is known. The portals are the Winterbole Passage, located outside Winterbole Forest in both the Feywild and Arundel; the Mage's Portal, located on the Mage's Isle; the Hielam Portal, located on the island of Hielam; the Passages of Silwen and Galavis, located near the two Elfin capitals; and the Clsinecret Portal, located somewhere outside the Greenhammer capital.
Feywild has no central seat of power, with each local area being ruled separately. The Faeries are known to have a Queen, but official contact between the reining Faerie monarch and the Eladrin has never been recorded.
The Eladrin uniformly worship Melora, Fey Goddess of the Sea.
All Fey speak Sylvan, the language of the Feywild, though most also have basic knowledge of Common. The ambassadors typically speak Elfin, and particularly powerful sorcerors may learn Draconic or the language of the Primordial.
Also, here's what happened immediately before the campaign started:
You enter the passage to Arundel, feeling more alone than you ever have before in your life. You look around at the mundanity of Arundel; this Winterbole forest is nowhere near as vibrant, not nearly as alive as the one you left.
Walking down the forest path, you hear a noise behind you. You turn, to see a club, rapidly approaching your head, and before you can react, you feel the pain of it colliding with your head. Despite your training, you soon lose consciousness...
City image by David Revoy, licensed under the
Creative Commons Attribution 3.0 Unported license.