The Nature of the Soul
Each living thing has a soul. From this fact one is forced to ask a good number of questions: What is the soul? Where does the soul come from? Is there a difference between the souls of animals, plants, and sentient life? Below are the answers to these questions.
Souls can have two parts: the base soul and the higher soul.
The base soul is that which animates the body. Without it the body can survive but can only fulfill the most rudimentary of functions. The base soul fulfills the function of animation. This part can be found in the souls of all living things- animals, plants, and sentient life. This part of the soul seems to be a part of the world in the same way that sunlight or magic is. It comes with life and seems continually reincorporated into it.
The higher soul exists in sentient beings. It is this which animates the mind in the same way that the base soul animates the body. Unlike the base soul, this portion comes from beyond the Material world. Each soul comes from a Deity and enters their chosen people upon birth. The higher soul grows over the course of a lifetime. As the individual learns and experiences life the higher soul expands. Upon death, by default this portion of the soul returns to the Deity this individual believes in. This growth of the soul over the course of a lifetime is what allows a Deity to make even more souls for the next generation.
If this natural cycle for the higher soul is disrupted it can be a blow to the Deity's Power. So long as the cycle is complete, no additional Power is needed to manufacture the new souls of their people. When an individual is converted, sacrificed, or their soul is in some way kept from returning to its originating Deity this is no longer necessarily the case.
Alternate cycles can and do exist. One example is that in which the Deity creates the soul, allows it to live the full course of its life and then enables it to live forever in an afterlife. The souls in the afterlife strengthen the Deity slightly, giving them most of the Power needed to continue the creation process of an escalating number of souls. There is a small loss of Power in this cycle, but there is the added advantage of giving a rewarding afterlife to the faithful. By default, these souls can no longer grow and learn as they did in life.