Here is what no mortal cartographer has ever successfully drawn, though thousands have tried.
The Multirealms is not a stack of planes. It is not a wheel. It is not a great tree with roots in hell and branches in heaven. All of those images are metaphors, and metaphors are lies that point toward truth.
The truth is an oblong - an infinite elongated sphere of fabric, stretching in directions that mortal geometry does not have names for. It contains everything that is, was, or could be. Every world ever dreamed, every god ever worshipped, every hell ever deserved. All of it, inside this one impossible shape.
You cannot stand outside it to observe it. You are inside it. You have always been inside it. Everything you have ever known is inside it.
There is no edge. There is no outside. There is only the infinite middle.
The Fabric of Existence
The oblong is not empty space with worlds scattered through it. It is more like a single continuous substance that exists at different densities. In the dense center - the Material Realm - reality has rules. Physics governs. A sword cuts because it is sharp, not because you believe it should.
In the upper reaches, where divine domains cluster, the fabric thins into resonance. Belief shapes matter. A god's word becomes law not because of power but because the fabric there agrees with their nature. In the lower reaches, the fabric is dense again but differently - compressed under entropy, suffering, and the absence of hope. Stone grows heavier. Darkness is not the absence of light. Hunger is law.
The Realism Gradient
The closer you are to the dense center - the Material Realm - the more physics governs reality. As you move outward toward the divine upper reaches, physics yields to intent. The fabric becomes responsive. In the lower regions, the opposite problem presents itself - reality is hyper-dense, entropic, resistant to change, resistant to hope.
Upper and lower are not judgments. They are descriptions of how real reality is in a given place.
This is why the Gate Keepers exist at the Ethereal boundaries. Not every soul can survive the shift in resonance. A mortal who walks directly from the Material into the pure divine would find their sense of self dissolving - their thoughts becoming landscape, their fears taking form around them, their past and future bleeding together.
Why Upper and Lower Are Lies
Mortals invented the vertical metaphor because mortals live on ground and look up at sky. The actual cosmological structure has no up or down. The oblong stretches in a direction that has no compass bearing. When a cleric prays upward, their prayer reaches the Ethereal and finds its way to their god through resonance, not altitude. The metaphor works. The mechanics are just different than imagined.
The practical importance: upper and lower are not literal directions. They are not sky and pit, heaven above and hell below. They are resonance positions within the infinite oblong. But the distinction is real. The Lower Realms are evil because their dense entropic fabric rewards cruelty, domination, hunger, despair, and decay. The Divine Realms are not "above" in any physical sense, and the Lower Realms are not "below" in any physical sense, but the moral danger of the Lower Realms is not a metaphor. It is part of what they are.