Multiverse

Each of the 7 Endless has a plane of Existence of their own. Destiny has his garden, Death has the Sunless Lands, Dream has the Dreaming (which mortals visit in their sleep), Desire has the Threshold, Despair has her mirror gallery, Destruction's realm is nameless and abandoned, and Delirium's Delusions span her entire home plane.

Inside the ring of Material Planes are the four elemental planes, Water to the North, Earth to the West, Fire to the South, and Air to the East. Directly past the borders of the Elemental Planes is the elemental chaos, a thin ring of chaotic energies that annihilates most of anything that enters it.

On the outermost layer of the multiverse are the material planes, modeled somewhat after Vemnos, each different in it's own way. Each material plane is linked with the Feywild and Shadowfel, and each Feywild and Shadowfel is unique to each material plane, but drawing more influence from the Inner planes. The Material Planes orbit the more Inner Planes, their location in their orbit determining how much influence the different Inner Planes exert on the Material Planes, and the distance between the Inner and Material Planes determining how great the influence of the Inner Planes can be, and how much magic can be found on the Material Planes.

At the center of the Multiverse lies the Mana Core, the source of Magic. From the Mana Core the Multiverse was born, and into the Mana Core the universe will die.

Past the elemental chaos lie the Inner Planes, the 7 positive planes, the 7 negative planes, and the 2 neutral planes. Each Inner Plane was imbued with power, which mutated, and became sentient. While only a basic consciousness, each plane exerts its will upon the inhabitants of the plane, and can theoretically be communicated with and bargained with.

The Outlands are also considered an Inner Plane. It is an amalgamation of the 16 Inner Planes, and has a very tentative balance. Each Inner Plane has a border town in the Outlands, and the only beings who stay in the Outlands are those who seek the Endless Planes, the homes of the Endless, or those who seek the mythical Prison Plane, Vemnos

The In-between places can be classed into one of three distinct categories. The Far Reaches, The Transitive Planes, or the Blind Eternities.

The Far Reaches are found past the infinite material planes. They contain energy that has festered into a madness that is more incomprehensible and corrupting than Delirium herself. To glimpse the Far Reaches is to become an aspect of it, both physically and mentally transformed. The Eldrazi are an excellent example of creatures that have seen the Far Reaches.

The Transitive Planes are the main ways between other planes. They are where Planar Gate spells will take you to, provided you weren't casting from a transitive plane. Most transitive planes are empty, populated only by naturally forming gateways and the beings wandering them.

The Blind Eternities, similar to the Transitive Planes, are a way between planes. However, only the Endless and Planeswalkers can easily access the Blind Eternities. To them it feels like a warm embrace and home, despite their short stay, and the lack of sight within it. To others, it is horror incarnate. There is no other way to describe it. Many an unprepared passenger has died from the shock of the Blind Eternities.