Universe

The Universe is the spherical volume of existence that contains and is defined by the six laws of creation. The Universe is all of space and time and their contents, including worlds, living things, thinking creatures -- all the myriad forms of matter imbued with the energy of life, spirits and magic. Beyond the borders of the Universe lies an endless expanse of impossibility known as the Void.  

Worlds as physical places

The Universe is filled with countless planes, also referred to as worlds, all of which are realms made of matter and energy populated by wondrous creatures and comprised of biomes varying from the mundane to the fantastic. The worlds of the Universe are numerous beyond counting and as varied as imagination.   Most worlds are physical realms isolated from each other, but there are also a few mirror dimensions that exist seemingly on top of each other. However, these mirror worlds are a miniscule minority against the countless multitude of other worlds.  

Between worlds

The worlds of the Universe are spherical volumes of matter that float in an empty expanse known as the Sea of Creation, sometimes also referred to as the Astral Sea or the Astral Plane. This interplanar medium is devoid of matter but nonetheless charged with positive energy and imbued with the powers of creation.   Beings with appropriate means can travel the Sea of Creation; magical flying ships move the warhosts of celestials and the githyanki from one world to another, and planar creatures such as astral titans use their innate magical powers of levitation to seemingly swim in the Sea of Creation. Many civilizations, godly beings and planeswalkers rely on teleportation to move around the cosmos, entirely avoiding the need to physically traverse the Astral Plane.  

World Tree

Matter that makes up the worlds of the Universe is arranged across the Astral Sea along a bipolar structure known as the World Tree. It is comprised of the five elements -- earth, air, water, fire and frost -- which exist as thin and elongated strands of immeasurable length. These strands are also known as the Elemental Planes. They are constantly in flux and are spun together in a spiraling structure that is more tight in some places and more loose in others.   A linear axis runs through the Universe from the Plane of Order to the Plane of Chaos. At the center of the Universe, five strands of elemental matter run along this axis in a spiraling helix -- the tree trunk -- that diverges into ever-expanding, forking fractals -- the roots and the branches -- towards the poles of the axis. These countless, fractal strands of matter reach all the way to the edge of the Universe but also curve back towards the center.   Where the elemental planes grow close and intertwine, the different elements mix together and give rise to the creation of worlds that can be inhabited by creatures. However, where the elemental planes separate and lie far apart from each other, the elements exist in their purest form. In such conditions the elemental planes are mostly uninhabitable by any creatures besides elementals and spirits.   At the center of the Universe, the trunk of the World Tree is so wide that the elemental planes do not intertwine. The only worlds found there -- the Inner Planes -- are the world of Amanor itself and several divine realms created by the Empyreal Gods. Where the trunk diverges into roots and branches the elemental strands grow close and weave themselves betwixt each other. Nearly all worlds of the Universe -- the Outer Planes -- lie amidst the leaves and the branches of the World Tree.   As the branches of the World Tree approach the Plane of Order their fractal structures and intertwining shapes become ever more regular. The worlds that are found closest to the Plane of Order are formed from perfectly equal amounts of the five elements. Conversely, the roots of the World Tree that fork out towards the Plane of Chaos become all the more irregular the closer they get to the end of the cosmic axis. Worlds that lie close to the Plane of Chaos are formed of wildly different compositions of elements -- most worlds are uninhabitable by mortals due to being made up of only one or two elements.