These are renders of the construction of the main building of Ikûl Tikis, a Ziggurat dedicated to the god of death of this world. The fortress is populated only by vampires after this same god cursed a dwarf in its temple.
In real life, Ziggurat are large temples built by Summerians. Some dubious sources says that they worshiped gods of mountains, and when living away from mountains they would build these temples as literal mountains, which is the most dwarven thing ever.
The 3D export was done with Vox Uristi (my own software) and rendered with MagicaVoxel. If you have any question or suggestion about Vox Uristi or the fortress, please go ahead!