Thaelas canonized as city of lightning. The city sprawling at the mountain's base is the city of Metal. Known for its peerless crafting (duh). The undergound cities are particularly developped under them, and despite numerous theories nobody really knows why.
((See, the thing of it is, though, the whole idea of the stair-city is that it started as a pilgrimage path that eventually grew into a city over time. The stair-city isn't meant to be all that special in itself other than the fact that it supports what's at the top and it's a rather fantastical construction. And I don't imagine it being a very metal place; it would be mostly stone or adobe in terms of materials and a lot of terraced farms and gardens to support the population.
((And actually, the whole lightning motif never really seemed to fit the top of the mountain that well, either. When the stormy desert was mentioned earlier, I thought that would be a better fit for it. Now that I think about it, ice would be a really good idea for the mountain top, so I think I'll make it that.))
The City of Thaefar, also known as the Grand City of Ice, sits at the peak of Mt. Thaefar. It is reached by climbing the Countless Steps which encircle it's perimeter in a spiral pattern up to the top, which has over the centuries grown into the magnificent Stair-City of Tolgrin, whose terraced farms and gardens feed not only itself but also the citizens of Thaefar above.
Near the top of mountain, below the City of Thaefar, there is a line all around the mountain where snow will always fall called the Eversnow. The path through this region on approach to the city is known as the Eversnow Pass, which is constantly cleared by the monks of the Snowpass Monastery, who do so not only as a courtesy to travelers but as a form of meditation.