Thereamid, adverb (†there-emid) amid that.
Being in a place between and in the middle, neither day nor night, here nor there; being within the passage between the worlds.
Once, the faeries of Europe were a force of nature to be reckoned with, placated, and never, never named. But ever since the end of the middle ages they have been vanishing, dwindling, disappearing, until the only fairies the Victorians knew were the helpless flower creatures, the true terror of the fairy rade forgotten.
Where did they go? Story after story tells us that they went over the sea, to a place far to the west. They called it by many names, including The Land of Youth. Time is different for those not of mortal blood. Those who joined in the fairy dances would sometimes discover that they had lost a week, a month, or a century. Oisin? lost three hundred years and returned to find an Ireland that was completely changed.
The Otherworld was always a place nearby, where the Good Neighbors lurked, accessible through ancient mounds and secret ways, a place where time can move in fits and starts. To some of The People of Peace, it was only a few years ago that they left the old world. The People have just started to notice that their iron-age neighbors have followed them to the new world. And now a congruence in time between the two world is starting to take place.
The place where the Others live, the Otherworld runs by different rules.
Force has a different meaning here. Modern technology is easily subverted by faerie enchantment, and much of the power of the Fae is directly applicable to subverting an army. Weapons can be turned to flowers or tigers, lights can lead victims astray and separate them from their companions, the entire landscape can turn into a hostile maze. But with the right sign and the right signifier a little child can escape without harm.
People tend to leave a piece of themselves behind in faerie, either literally or more often figuratively. The things that you encounter there will change you permanently. And in some cases you may never be able to find your way back.
To a human, the rules and the morals of this place are very alien. The motives of the inhabitants are sometimes incomprehensible and always of an unhuman nature.
The place between the worlds is a liminal space, disconnected from the flow of time in both worlds. It is a no-place of no-things and no-one, but it can only be entered if a very specific condition can be met. What that condition is varies for every entrance, and sometimes for every person.
You have a great deal of leeway in your contributions, but there are a few inviolate rules of the setting, and a few guidelines for writing better stories and characters. Check out the Genre Guide for more details.
The original document is available at http://www.thereamid.com/tiki/TheSetting