Followers are the economy. Between crusades, they are what keeps the cult moving.
What they do
They gather resources, build, and hold faith. A cult with working followers funds crusades without you micromanaging every task.
Who to keep
Keep followers who are loyal and useful: high faith, no grudges, and a trait that helps the cult. A happy follower is fuel for rituals and builds.
Who to use
A follower who has turned, or one you have too many of, is a candidate for sacrifice. The ritual returns value to the cult instead of leaving dead weight.
Happiness
Happiness is food plus rules that fit. A follower who is fed and agrees with your commandments stays. One who is not becomes the leak that drops faith.
The follower database lists every type and what they bring, so you can plan the cult instead of guessing.
Recruit the labor, drop the dead weight
Followers have traits (industrious, sickly, etc.) that change what they contribute. Keep industrious ones for farming and building; sacrifice or exile traits that only cause trouble. A larger cult farms more but needs more food and beds, so grow it in step with your base, not ahead of it. Recruited enemies from crusades are free labor — convert them before you spend resources on new ones.
The database is your plan
Before a big ritual, check the follower database for who meets the requirement, so you sacrifice the right one instead of a farmer. Planning the cult from the list avoids the “why is no one farming” moment after a purge.