Another reason, could be evolution of the soul. In prehistoric times, the karma of most human beings was fairly young, and so "primitive." The higher astral vibrations were unknown of, and so during an OBE, before or after death of the body, the astral double or etheric body which housed the consciousness, went to the lower planes.
Energetically, the cosmos during it's beginning half was journeying downwards, towards the void, and only after reaching where things should have gone still (stasis), the moving changing energy that is everything, found it didn't stop, but bounced backwards towards the source, creating the second wave of the cosmos, where energy is moving back towards the source.
The earliest and most remote Shamanic cultures usually describe the early world of the first peoples and or even before humanity, as having a dream like quality. Superhuman feats were common, and this time of myth was described as being when everything was very young.
This makes sense, as the early times are about massive energy, and so amazing possibilities, where as the later times are a slower more formed flowing energy, where limitations like the laws of physics, have the upper hand.
Anyway the Shamanic Underworld, was the abode of the dead. Dark monsters also lived here, as nature dying was warped and mutated. These creatures usually hate light, as it burns or blinds them or other unconfortable sensations.
The dead were divided into two primary types. Ghosts and Wraiths or Banshees. Ghosts usually were quite human like, but often forgetfull, and seemed "lost." They were translucent in form, and resembled the lifeforce when it was thin like spider's silk.
The Wraiths or Banshees though, were malevolent and tortured souls, who were twisted often by entropy and dark in appearance, and spacious in shape. They often were seen feeding on the lifeforces of the freshly dead, and tried to drain or kill the living by their cold touch, to which shamans were called to repair the energy or vital body, by getting back "organs," or pieces of the soul, which the shades had taken.
Naturally, also the evil souls dwelled in the Underworld, and even bad natured animal souls, and were often twisted in form, and greedy and angry in nature. These too were seen as sometimes attacking the living. It is these spirits which were later to be called demons and devils, and made the great tortures and rulers of the underworld, and the evil among men.
Hell is different from the Underworld, as it is a place of tormet, verses death and dying and destruction. The Egyptians, Chinese, Norse, Mesopotamians, and others, had legends of Hell. In all cases it was a special place of the underworld, where the damned dwelled, not merely the dark or dead.
Anyway, as people began interacting via magick with the dead, and exploring nature, they came across the Upperworld, or the Heaven(s). Soon it was realized that the righteous souls, and powerful shamans came to live here, skipping the underworld when they died or explored duing an alive OBE, and these became the first gods, devas, angels, and other aerial spirits.
Dispite civilization and time, the Shamanic Underworld is much still the closest truth to what actually lies in the lower astral, today, but many do not know this, as they are taught the lower planes are just dangerous and a place of evil and so the Hells.
Shamans, Necromancers, Mediums, and others who deal with the dead have a different story to tell, and it's infact the lower astral we first inhabit and explore when we die, and we do not immediately "go to Heaven." Though we may have immediate visages of it, as the higher planes open up and send light down below to guide the dying or astral traveller.
Edited by ChaosTech, 25 February 2012 - 07:38 AM.