Cosmology is the study of the structure, organization and composition of the planes of existence. There are many interpretations about the organization of the Omniverse. Most of them use models that attempt to reduce complexity and sheer volume of information into concepts that are understandable and even useful to the brave, the curious, and the ambitious.
Among the planar types in the Milegu are the Material Planes, the Elemental planes, the Astral Planes, the Lower Planes and the Fractal Planes. The interconnections between Planes are globally called Qrosses. Within this name all types of portals, cracks, crossroads or passages between planes are grouped. The Planes (as well as any other entity) belong to groups of homologous entities, called Shains. Both Qruzes and Shains are grouped within the concept Qs.
There are planes that are inhabited by impossible creatures on the Material Planes, and other places and beings that even defy the definition of Plane. Whole sections of the Omniverse escape knowledge in the Depths of the Alpkatchen, such as the Abstract Domains or the Mathematical Domains.