One of the first things mentioned about Project Eternity was the concept of Souls being important and a source of power, that you were interested what world building ideas are generated from that design mechanic.
Where did the inspiration behind this concept come from ? I've heard many people mention NWN2: Mask of the Betrayer, although I personally thought of Lionheart: Legacy of the Crusader.
It actually came out of some thoughts I had about the physical and metaphysical underpinnings of our own world. When worldbuilding, I think a lot of designers want to explain everything up front. There's obvious value in defining how the world works because it helps everyone wrap their heads around what the setting is about. Over the years, I've felt that breaking down the supernatural into easy-to-comprehend chunks drains the magic from it.
Compare this to our own observation and understanding of the physical world. Public reaction to the discovery of the Higgs boson particle was very telling. Despite the scientific community's general requests to stop calling it the "God particle", the public and media couldn't help themselves. A discovery that potentially explains, if not the "why", at least the "how" of existence is appealing.
Project Eternity's world has a similar level of flawed understanding. They can perceive souls, they can detect and record some data about them, they can verify their findings to a certain extent, but they still don't really "get" how it all works. Arguably of greater importance, they don't understand why souls work (and don't work) the way that they do. Individuals also don't agree on the role the gods play in the cycle. Last week, our art director, Rob Nesler, came in and asked me, "Are the gods actually gods or just beings of immense power?" While there aren't many people in the world of Project Eternity who deny the existence of gods, that question is one that people in the setting have debated for millennia.