The Krystal Narbe
At the northern end of the empire the gentle seaward slope of the lowlands is abruptly shattered by a sheer cliff face that approaches 600 meters high at its tallest point. The base of the cliff is rough and looks almost buckled as if the cliff was forced directly up out of the ground. The height of the Narbe drops dramatically as you move westward towards the inland jungle allowing access to the Northern Table where Skyhome and Watchkeep are located. The most odd thing about this cliff is that it seem to extend into the eastern sea itself, the waters around the north of the empire being measurably more shallow than in the south. There is a great waterfall at the western side of the Narbe that feeds the great river that sustains the empire.
The Northern Table has a rich ecosystem much different than the lowlands of the empire but the Narbe it's self seems almost unnaturally bare, with only the crystal violets that grow from the mage-glass deposits in it's face.
Severe storms and high winds are not uncommon at the base of the Narbe, making any attempts at climbing it more difficult than the height and sheerness alone. Shadehaven, which lies at the west-most point of the Narbe that is within the empire is overcast and rainy more often than anywhere else in the empire.
The Krystal Narbe is the only place in the empire where Mage-glass can be mined. This strange substance is as clear as glass but can be melted down and worked like steel. It is harder than any other material in the empire and a mage-glass blade can be made so sharp it's said you could cut a moth in half on the wing.
The history of the Narbe is somewhat debated among the scholar caste, with the predominant belief being that it was created by the gods. The closest thing to pure fact the imperial scholars know is that it was created during the Breaking of the World, though why or how is unknown.