At the start of a post-Eclipse campaign, formal magic should be rare and poorly understood by most people. The world contains witches, spiritual practitioners, and old knowledge, but the average village priest or soldier cannot cast magic like a standard fantasy wizard.
Folk belief is everywhere. People believe in curses, saints, omens, demons, blessed water, charms, old trees, forbidden caves, and spirits of the dead. Some beliefs are wrong. Some are symbolic. Some preserve fragments of real astral knowledge. This lets the AI create mystery without turning every superstition into hard mechanics.
Witches and true spiritual experts should be rare, secretive, and cautious. They may understand the Interstice, spirits, wards, and the danger of brands more clearly than the Holy See does. They should not instantly explain every mystery or solve every threat. Their knowledge often comes with social danger because the Holy See may persecute practices it does not control.
For gameplay, use low-level magic through rituals, wards, talismans, herbal cures, dream interpretation, spirit communication, and protective circles. True large-scale magic should feel ancient and exceptional.
A good rule: common people have religion, witches have technique, apostles have corrupted power, and the God Hand have cosmic authority. The party should feel the difference between these layers.