Pineal Gland
The organ which produces the hormone of darkness, melatonin, it is tied vitally to a human's ability to interact with the Dark. It is therefore a vital interest for a seeker to keep his pineal gland healthy. To others which seek to protect themselves from the dark, the opposite is true.
Pineal gland calcification protects humans from incursions by ethereal Others. It is accompanied with an unpleasant side effect of an inability to experience natural and healthy sleep.
Worldly powers conspire to protect their citizens from the Dark and thus have set forth on a decades long campaign to accelerate Pineal gland calcification in normal humans, or known colloquially as "normies".
This plan was first formalized by the Fabian Society. It was later ratified in various tertiary groups, chief among them the Club of Rome. Actions were discussed and agreed upon to suppress cult activity and keep normies from the Dark.