Variously called the Blight, the Wastes, the Bane, the Zone, Bad Spots, Nightmares, and the Rot, these are the uninhabitable areas of Tarkishi, which include most of the western two-thirds of the nation as well as some portions of eastern Tarkishi.
Guides--the stronger and cleverer the better--are required to avoid the worst of these places and navigate the ones which are merely bad. Guides are uniquely trusted among Tarkishians, possibly because their honor code precludes taking advantage of anyone who has paid them to assist. Of course, as soon as they fulfill a bargain, the honor code no longer applies, but generally, this is about as trustworthy as a Tarkishian ever gets.
Though all the Tarkishian city-states have names for the wars that devastated their confederacy, most of the people just think of them as "the Wars."
Mages and casters of unspeakable power went at it hammer and tongs to try to take over the Confederacy, which at that time had conquered most of Meneluinin as well as part of Solitaire.
The conflict came to a sputtering halt when the most powerful remaining combatants disappeared, along with Vigil, the nation's capitol, and everything in it. No one knows what happened to it, and generally, people give that entire area a wide berth.