I usually avoid the topic of religion when I design or run games, except as backgroud/setting fluff. This is largely because most people (IME) don’t seem to want to play clergy. Also because it can be a bit of a sticky issue when it comes to players with strong religious beliefs, especially with newer players.
So I am now turning my thoughts towards creating different religious beliefs. The first one in my mind is a worship of the four basic elements (or more if you go for the Asian ones). Those faithful to an element, return to that element upon their death. Different ways of life follow different elements. You could communicate with a deceased loved one by travelling to their element and attempting contact.
- Fire- passion and war
- Water- Life and secrets
- Air- Stealth and death
- Earth- Security and riches
At Least that is my current thinking, I will clean this up at a later date.