When an individual dies, that is not the end of them. Their spirit moves on to reside in another plane to continue its existence.
When a person dies, their body is prepared for burial through a very precise ritual. During this ritual, the ones preparing the body recite, over and over, a type of prayer. The words of this prayer are spoken in the holy tongue and give the spirit instructions on how to proceed to judgment so they can continue their life in a spirit-deified form.
While the body is being prepared for burial, the spirit of the person finds itself in the Halls of Judgment, lost in the maze of it all. It is only by listening to the litany recited by those preparing their body and repeating it to themselves can they make their way through the maze and find the Room of Scales.
While they wander through the halls, they can return to the world of the living and watch their family and friends and observe the events of the world, but they can only interact with the world in limited ways. Chills, foreboding feelings and minor mischief are all the powers they are granted in the living world before their judgment.
Once in the Room of Scales, the god of death weighs their heart against a feather provided by the goddess of order and right. In their heart is stored the weight of all their deeds performed in life. Evil and selfish deeds weigh more heavily on the heart while righteousness makes their heart as light as the feather. Those whose heart balances with the feather are taken into the divinity of the god of death and are released to continue living their spirit-lives in a reflection of the world of the living. Those who are found wanting are cast down into the cold river of death where they languish in hopelessness.
The divine spirits, the ones whose heart balanced, are granted the power to manifest to their loved ones during times of need. While they still only have limited ability to interact with the living world, they can appear in a spiritual image of themselves to give help and advice. This costs the spirit a great deal of energy and so is done only in times of great need.
Spirits who fail to find their way through the Halls of Judgment to the Room of Scales are lost in limbo. They are never weighed and so never receive divinity or banishment to the river of death. Such lost spirits wander the land of the living or the Halls of Judgment forever, cursing the lives of those who draw their ire, until such time as someone recites the litany over their grave, allowing them to find the Room of Scales, or their spiritual form is destroyed by Faith or by Magic.
The divine spirits who continue their lives in the spiritual reflection of the living world maintain the status their bodies were buried with, living the best life they can with the goods that were left with them. When they do trade with the other divine spirits, they trade the one thing that has any meaning: favors for their living relatives. Divine spirits tend to avoid the lost spirits completely. Their is no war or conflict in the Realm of Spirits. Only peace.