A land that, at least for the outside world, has passed into legend. This small continent was sealed off from the rest of the world about 1000 years ago by the great magic and military powers of the time
Various legends tell of a creature called Drachus who raised an army of undead to take over the world. His designs for world domination were foiled by a coalition of countries who were determined to stop the advance of the undead hordes.
Contact between Eisor and the outside world is nonexistent, and many stories have popped up in the intervening years about treasure hoards and other fantastical things hidden in the sealed land.
From the outside, Eisor appears to be nothing but a wall of distorted air. Touching the barrier between Eisor and the outside world seems to yield no effect, and no known objects or magic seem to affect the surface.
Eisor being sealed off had a significant impact on the climate of Overworld. The most notable effects are higher water temperatures and a vastly changed jet stream. These two changes have led to much of the arctic regions thawing, and allowing passage into Halicarn.
In addition to the above, Eisor also casts a long rain shadow which has turned much of central Erevil into a desert.