Madrius Dark Sun
A parallel metaphysical realm exists on Athas. It is the realm of the spirits, which has a strong bond with the mana realm. There is a thin veil that separates the physical and the spiritual. Some beings have the ability to cross freely from one realm to the other. Others need a catalyst. Beings that are naturally in tune with the spirit realm can often catch glimpses of it from an early age. These people are often thought to be insane because of their “imaginary” friends or “absurd” visions. In fact, the spirits frequently seek these people out, especially those sympathetic to their cause – whatever it may be. Those selected often become champions of the spirit world. Shamans, duids, and other primal characters become more in tune with nature thanks to the guidance of the spirits.
The spirit realm is not a place that the dead go to once they pass away. It is also not like the generic “fey” realm of other campaign settings.