Fundament of the Soul's Fugue

Normally a soul freshly separated from it's body through quiet death is shed from a shard and wanders the aether until it is ushered to a shard with this fundament. Living things that die on this shard never naturally leave this shard.   A soul is retained in the material of the shard until it needed by the shard to create a fundamental population. A soul can also be incarnated through the population that currently live on the shard.  

Amateur Psychopompy

Travelers to this realm whose knowledge of the occult or divine is sufficient enough may be able to interpret where a particular soul is being retained on such a plane. Locating a specific soul in such a way is a difficult task that requires specialized tools or magical incantations although the isolation of the soul from the environment is a simple matter requiring purification reagents and retention implements to store the person. The resulting crystalized soul is a reagent that waives half the cost of what it takes to perform a ritual used to bring them back from the dead. On such fugue worlds finding and attracting souls in this way has become a lucrative business for the more unscrupulous types- although their services are incredibly useful to have on retainer.