Worlds and Realms

"Think of Realms like islands in the sea, except every island is also touching several other islands at all times. And probably has its own islands inside itself and the distance between islands is changing all the time... you know what, forget what i just said."

— Miriam, Realm traveler

A "Realm" is a dimensional location within the multidimensional universe of the Brass Realms. A Realm is best described as its own, self-contained world. How this world looks or functions can vary greatly.

Material Realms

The "Material Realms" or "Mortal Realms" make up one part of the Brass Realms. Material Realms are a collection of self-contained worlds governed by immutable laws of physics and causality, with each Realm being a sort of bubble that floats in the Astral Sea.

Living worlds: The worlds and realms created by the gods as part of The Dance of the Worlds are made from the raw matter left over from The Splitting of the world. They are alive to an extent, they are sapient and speak their own language; World-Song.

Realm Travel: Realm travel generally occurs by means of Realm-gates, Nexus Keys or some other means of portal-creating magic to allow a mortal to step from one material realm into another. This is by no means common or easy but it is not some kind of lost art either.

Realm Shell

A material realm is separated from the Astral Sea by a Realm Shell. This is the invisible barrier between the Star-Sea and the realm in question. The Realm Shell is formed out of Arcane energy that is sourced from the Divine Machine and is critically important in sustaining the realm's laws of reality.

Realm clouds:

Realms appear in the Astral Sea in the form of 'Realm clouds'. These worlds are not openly accessible or even clearly visible. Instead, where the worlds float in the astral they cause a faint gaseous outline of the world to appear which shares some traits with the world it belongs to.
If portal-creating magics are used on these clouds, it is possible to create temporary gateways to cross into a world. If one uses similar magic inside a world, it will create a gateway into the astral instead. Few creatures and civilisations can withstand the torrential currents of the astral and sail its tides, but some exist.

The Spirit World

Main article: The Spirit World.
The Material worlds are not all there is to the brass realms. There is an entire second set of realms, hidden away from mortal eyes: the spirit world and its associated spiritual realms of gods and immortals.

Similarly with how all material realms float in the astral sea, the spiritual realms (also known as domains) are like spheres of civilization and power seperated by wild nature, kingdoms inhabited by the immortal servants of the gods and ruled by the gods themselves.

Visiting the spirit world is not generally possible while still alive, and neither is it possible to take anything along for the journey. The journey into and through these places is a journey of the mind and soul, not of the body. Certain mystical procedures exist to allow mortals to visit the spirit world temporarily, however.
A wandering soul or visiting mortal mind must then find their target destination by wandering the mists of the spirit worlds and attempting to reach them.
The Locations of these worlds as well as what is within them is fluid and depends more on the visitor and their state of mind than anything concrete, objective and constant. The nine hells for example are pits of vile evil independent of what cultural norms one has, for they contain them all.