Spiritual belief: A trait you gain after around 150 deaths.
Allows spirits to form after dead bodies decompose. A 1/10 chance of happening.
Around 0.005% happiness every 5 ticks for each spirit.
Spirits can watch over people. While being watched over, the person will have a less chance of being hurt and being sick, depending on their current job.
A person can be watched by up to 3 spirits.
Spirits will choose one person to watch over. If the person dies, the Spirit will go to someone else, or leave. This depends on your happiness. 0% is a 1/3 chance of going to someone else. 100% is a 2/3 chance.
If population is low, spirits may stay, but will not watch over anyone, giving everyone a very minor happiness boost. (0.00005%)
Spirits can bring a new ending: Watched ending. This happens when you have no population left, but have at least 10 Spirits at that time. Fairly hard to get. After you get this ending, subsequent playthroughs will gain you more Spirits.
After every ascension, Spirits get a higher chance of forming and going to other people.