Yamkath, the Celestial Reaches

Credits to Devit Gvalia on Artstation for the awesome cover art!

Home to Yamma and almost all celestials, Yamkath is both the heavenly divine plane of cloud-piercing spires and the highest point of Gahelas, Elemental Realm of Air. Opposite of Xaecreotis, Yamkath is a near endless expanse of white, impenetrable clouds, pierced by ranges of impossibly tall mountains of grey stone streaked by white marble. Before the Reckoning, many ranges were connected by mountain-spanning cities. Great towers of marble connected by bridges of gold and steel rose from the spires of Yamkath's peaks. The greatest of these cities was the Silver Spires, a metropolis of gilded structures that connected the mountains of Yamkath's most central range. At the heart of the Silver Spires was the Aigacerama, Yamma's personal monastery and home. Aigacerama was perched at the top of the tallest, most central mountain in all of Yamkath -- indeed, the mountain, known as the Great Pillar, is the tallest mountain in all of Yophas -- and from it, Yamma could observe his Eternal Design in peace.

Inhabitants

Yamkath is mostly inhabited by celestials, such as angels and their creations, as well as pegasi and the like. Earth and air elementals roamed the spires and clouds, respectively, and some of the wisest and most ancient dragons have called Yamkath's countless peaks their homes. It hasn't been unheard of for genie merchants and even cloud giant castles to come and go through the Celestial Reaches, and some of Yamkath's mountains have been carved up by stone giant clans. 
Despite all this, there are still malefactors amongst the infinite expanse of this plane: entire goblinoid empires have been found hidden within the caverns of mountains, and not all dragons that have resided in Yamkath's peaks have been good-willed. Indeed, in the time since the Reckoning, Yamkath has become increasingly wartorn and embattled. Draconic empires and giant kingdoms have begun to lay siege to those angelic cities that still stand, and others still -- including the Silver Spires -- have been abandoned entirely, with their celestial population devastated beyond recovery in the Reckoning.

Travel

Yamkath can be reached by the usual planar magics, especially with the properly attuned lodestones and the like. One can also reach the Celestial Reaches by way of navigating the Realm of Stars, or by attempting to reach the highest, furthest from the Material Plane climes of Gahelas, the Cloud Isles; however, travel within Yamkath is much more difficult post-Reckoning. Little of the infrastructure remains that enabled non-celestial travelers to get around Yamkath remains. As with so many planes, the Reckoning brought an end to most multiversal trade and travel, and so the systems that prospered from them died as well. Now, one must have access to teleportation magic or means of flying to get from peak to peak, and be capable of defending oneself until they reach the safety of the remaining celestial bastions.

Type

Dimensional plane