City of Greed
The multiverse consists of the Material World, and it’s co-terminous planes; the Inner sphere of elemental planes, and the Heavens stretching infinitely above and the Underworld stretching infinitely below.
The Heavens can be reached either through astral travel or by flying for several hours into the sky and transiting into the ethereal plane before colliding with the Great Cloud Barrier. It is home to angels, and other celestial beings as well as serving as the final resting place for any elves who have fallen.
The Underworld can be reached either through astral travel or by traveling deep into the earth until one reaches the Adamantine Shell separating it from the Material World. Once at the Shell, one must transit into the Shadow realm and fall through. It is home to demons and other infernal/fiendish beings, as well as serving as the final resting place for dwarves after they complete their life’s work.
The elemental planes can be reached either through the astral plane, or through various portals scattered throughout the Material World that correspond heavily with the appropriate element. The only exceptions are the Negative and Positive energy planes, these can only be reached through astral travel.
The ethereal plane and Shadow realm and co-terminous with the Material World, but exist as either a near celestial version for the ethereal plane, or a near infernal version for the Shadow realm. Human souls can often be found travelling through these realms prior to being reborn into their next life.