Invisible Kingdom

From Praemal

Nearly 2,000 years before the Grailwarden dwarves founded Glangirn, the area around Green Mountain was home to a human magocracy now known only as the Invisible Kingdom. What links the kingdom had to the mages of Kem, and whether or not their doom is related to the doom that befell that nation, is unknown.

Few artifacts exist of this civilization, which had vanished long before the dwarves settled in the area, and the kingdom was too obscure to merit mention in the Fables of Burdock. The Tulgey Barrow is one of the few Invisible Kingdom sites that remain, and features the kingdom's hallmark use of mirrors, shadows and owl motifs.

The Register of Ancient Days does have more to say on the kingdom, however.

Invisible Kingdom sites

The Tulgey Burrow is apparently an Invisible Kingdom storage facility or fortress of some sort, at least in part.

According to Khenemet-Apep, there are kingdom-related ruins in the shadow of the Great Tower in northern Kem.