The elemental planes, separated by para-elemental planes, surround the realms of the gods. From each of these (except for the planes of Smoke and Mud) flows a river, field or valley, running from the outer 'elemental' plane to a central area known as The Verge (The Verge was once the stronghold of dragon and giant entities, however Saradanthule and others have since cast them from here into other realms and planes). Additionally there are a river of blood and a tunnel of light that flow from the outer rim. All these "rivers" flow into what appears to be a rift in between planes called The Abyss. It is thought that this central area was once a large lake but upon his birth the Dark God destroyed it and in doing so ripped a hole in space and time - creating The Abyss. Floating above the Abyss is an amalgamation of pieces from all the elemental planes (and possibly the remnants of the lake where the Abyss was formed).
Since its creation evil creatures of all types have developed within the Abyss, some warring with each other and leaving to establish the Nine Hells in the Inner Rim between the rivers of Fire and Blood. This realm has been the home to the eons long Blood Wars between demons and devils.
The Planes of the Gods are found along and between the various rivers, hanging like grapes on a vine e.g. Heliopis in the diagram, is the home of the Nyaatan Gods. Within Heliopis there are many realms of individual gods which can vary according the the gods desires, but that plane is the home to the Nyaatan Pantheon.
Surrounding the Prime Material Plane are the Spirit Realm (Positive energy & light) and the Plane of Shadows (Negative energy & darkness).
Travel Between Planes
You cannot move from one plane to another (except through portals) simply by moving towards another. The exception to this is in the Verge where one can move around the Abyss (and into it) including the uppermost layer of the Nine Hells - (Avernus). Travel to the elemental planes and planes in the outer and inner rims is only possible by travelling through the Plane of Shadows and Spirit Realm. There is no ethereal plane connecting to the cosmo of Kage and any reference to spells or that plane instead means either the Plane of Shadows or Spirit Realm.
The Grey is a limbo-like place where those who do not worship or do not believe in the gods go, rather than transcending to their gods realm. It is a grey endless realm of nothingness, with barren deserts, seas and floating islands in the skies. There is conjecture that this realm is forged from the bodies and realms of dead gods, which in turn form pocket or demi-planes within this land of nothing.