The rumors of satanic black-magic animal sacrifices and the pentagram ritual were nothing but lies spread by the church as a smear campaign against their adversaries.
Langdon quickly explained how most people pictured satanic cults as devil-worshiping fiends, and yet Satanists historically were educated men who stood as adversaries to the church.
The priest whom the Illuminati had inadvertently brought to power by killing the Pope had emerged as a worthy adversary.
There are no more uses of "adversary" in the book.
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Then, again, our military training is in many respects superior to that of our adversaries.
Thucydides -- Pericles’s Funeral Oration
Finally, it was rumored, there would be complete information-sharing among all of these previously disconnected and even adversarial entities, and when they were coordinated, and once all the health data they’d collected was shared, most of this made possible through the Circle and more important, TruYou, viruses could be stopped at their sources, diseases would be tracked to their roots.