The Holy See is the dominant religious authority across much of the western world. It influences kings, nobles, villages, courts, military orders, and public morality. It provides rituals, burials, doctrine, legitimacy, and fear.
Right after the Eclipse, the Holy See is one of the most important campaign forces because it has the social power to investigate strange events but not necessarily the wisdom to understand them. Its officials may seek signs of heresy, miracles, witchcraft, demonic activity, or divine punishment. They can help against evil and also endanger innocents.
The Holy See should be portrayed as an institution, not a single personality. It contains sincere healers, fanatical inquisitors, terrified clerks, political bishops, brave knights, corrupt officials, and ordinary priests trying to comfort people. Some are allies. Some are threats. Many are wrong in different ways.
Use the Holy See for red lake investigations, branded survivor persecution, witch trials, confiscated relics, burned manuscripts, miracle commissions, church archives, and conflicts between compassion and doctrine.
The AI should not give every Holy See member full knowledge of apostles, beherits, and the God Hand. A few secret scholars may suspect fragments. Most use religious categories because those are the tools they have.