Origionally the dwarven city of Karak Avrun, Avernii has been a human city for several hundred years; the dwarven retreat linked with the rise in the increase in goblinoid population and the conflicts that were escalating in the Sparshad area in that time period.
Avernii is now the greatest human bastions, with not just a perimeter wall, but several parallels centering upon the palace. Each way in to the city is guarded by forts and enclosed by barbiacans of differing sizes, thought to be dependant on the severity of threat of attack upon that gate. To call the city a fortress is an understatment as each square foot was designed with defense in mind. Although re-purposed over the decades to allow for human day-to-day living, high levels of security (by human standards) were maintained. Over a month ago some sort of great civil unrest occured and messengers were sent out for aid. Whatever has occured in Avernii would have to be dire indeed for the proud people to call for help from all corners; especially the Eastern Empire that they refused to be part of in its inception.
Avernii is a city state and had certain annexes that lay outside of the city proper, Tor Aln lies to the North of Avernii along the road that leads from the Wildlands in the North to the Chaos Gate, a massive, multi sectioned area of the city that is the second strongest outer defense in the city.