I had this idea for a setting, it might tie into an existing project, probably the Dark Places. It works on the idea that their are people with a divine spark, fractured essence of a primordial entity splintered into billions of fragments. Some people have more, some people have less. Those with less are capable of conscious thought, those with more are able to wield control over the world around them. In the old days, there were less people, so you get stories of Methuselah living to 969 years, epic heroes with amazing powers... the excess primordial energy occasionally infused animals and plants, giving them sentience as totems, and at times a convergence of excess power caused entities without physical grounding to spontaneously manifest (such entities might be referred to as gods, angels, spirits, demons, etc.).
As the population grew, the amount of excess energy waned. Fewer totems and non-physical manifestations occurred. In times when the population threatened to leave no excess energy at all, spirits would send plagies and wad to cull the pulation and refresh the excess energy reserves. A petty, greedy and vindictive trickster spirit rose to prominence over centuries, claiming energy for itself, teaching mortals how to limit the flow of energy to other similar entities, and eventually banish them from the mundane world. This trickster claims to be the one God, the alpha and omega... "him who is called I am". One of the most reliable ways to distil and extract soul energy from the universe is to birth followers and have them killed in your name. The trickster banned it's followers from contraception to maximise the mortals extracting soul energy from the universe, then devised "last rites" and deathbed confessionals to ensure the energy came their way.
Eventually there was no excess energy. The surviving spirits fought over the remaining energy, not seeing the true threat. We can add more analogues to history here, but we'll move through the "Age of Reason" when miracles were disclaimed and forgotten, through to the modern age. But we'll move to more recent decades umder the cosmology. More mortals are being born into the world and there was no energy to infuse them. The trickster doesn't want to give up the energy it has spent millennia accumulating, it hasn't released energy back into the world by invoking miracles for centuries.
Mortals are born without souls, without the divine spark. At first only a few, unnoticed among the masses. After generations, their numbers increase exponentially.
These mortals have no divine spark, they are null entities in the universe. Any semblance of a soul is a reflection of the souls around them, some even claim that they absorb that soul energy to function, draining the people around them. These a called the "Reflected Souls", often contracted to "R-Souls" (the wordplay amuses many of the spirits and other celestial beings endlessly).