Fall of the North
Currupt Mythal of fallen city
The Mythal used to be in place to hold aloft as well as other functions of a former Nethril City. The Mythall was then asundered after the temp. destruction of the weave. When the weave was restored it was slightly damaged with a now half buried city on it. Over time it was found by Augratha the Mad who studied it to use as a means to turn her into a Shan. She was interuppted during the process and this caused her to become trapped in the mythal along with 2 other creatures, one a dark diviner from Myth Drannor whom was seeking her, and the other a phaerimm.
The mythal was then again discovered hundreds of years later by a shade from the city of the Shade after they returned from the Shadow plane. The Shade sorcerer then curupt the mythal further by comining it with the shadow weave.
It can now be used by a mage or sorcerer to cast spells through it. There are other powers which have yet to be discovered by the party.