PS, or Photoshop, is a raster graphics editor used to create and enhance images. To create a three-dimensional (3D) spiritual fortress using Photoshop, one would typically use layers, filters, and 3D tools to design the structure. This involves creating a base shape for the fortress, adding textures and details, and possibly incorporating lighting effects to give it a realistic appearance. The process might also involve using 3D models if Photoshop's built-in 3D tools are not sufficient.