Spirituality is defined by the relationship between the mortal plane and the three spiritual planes (celestial, neutral, infernal).

The continent of Eryst resides on the mortal plane. All souls of beings who die on the mortal plane are sent to the celestial, neutral, or infernal plane depending on which deity they worship. If a soul is pledged to a deity, the soul will be sent to whichever plane their deity is bound to. Souls that are not pledged to a deity are sent to the neutral plane, where they are overseen by a purely neutral deity who rarely chooses to get involved. A pledge can be formed between a soul and a deity only with consent from both parties, but once the pledge is formed, the deity has complete control over breaking the bond.

If a deity moves between planes, all souls bound to that deity move with them, so politics between deities impact the souls bound to them. Deities have personalities and agency and they plot and politic amongst themselves. Deities can be forced from their plane to another plane if they are overpowered by the other deities on their plane, and they can force their way onto another plane if they are powerful enough, but this is very difficult and almost never happens.

A deity has a base amount of power granted by their divine spark, but most of their power is based on how many followers they have and how devout those followers are. Deities are very invested in what is happening on the prime material plane because they want to increase their followers and decrease the followers of opposing deities.

A deity can support a number of paladins and clerics based on their power level. Minor deities can only grant power to a few followers, and even the strongest deities can only empower a few hundred followers at most, so they want to choose carefully. Deities rely on their agents to use their power to protect their followers and increase their influence.