The city was the city of the realms. Within this city was a composition of all of the planes (from the great wheel cosmology). This was the great and grand work of the warforged during the heigth of their empire. It was built over the northern elven lands where at the time the warforged had the majority of their empire from their conquests of the elven kingdom the city caused a large number of advancements of technology and magic and brought alot of unity between the planes. It consitantly had a large number of coups and small warfares raging at any point of time. but it also brought a large ammount of trade and commerse into the material plane and many others. there are many theorys as to the reason that the city fell but the commonly though one was that all the exrtraplannar races did not like the taxes the warforged imposed and that with their assistance the dragons way last to the land and pushed it out of the sky into axil causing the city sea as well as the large valcanic hellscape to the north its rumored that in the terrory alot of extraplannar creatures roam but nothing can stop them because of the dangerous waters as well any inabillity to move onto the landscape and many islands. many efforts have been made but communication and transportation made it a futile effort. no one knows much about the lands beyond that it is a large graveyard and a reminder as to what the outerplanes and dragonoids plan to do with the material plane.