The Dresden Files is an interesting one, actually.Elheru Aran wrote:From what I recall of Dresden Files, the way that 'verse handles the 'masquerade' is liberal amounts of "this weird shit happened but there's a totally plausible explanation for it, now forget the actual weird shit" spells being thrown around. Concealment spells, spells that prevent mundanes from seeing the Fair Folk or the vampire courts, things like that.
The justification... mm... honestly I'm not sure there's one. Generally the notion, I think, is that if the mundanes knew of things like the Vampire Courts, there might be mass panic or the Vampires might decide it was open season in the name of self-defense, something like that. The magical organization that Harry Dresden is nominally a part of is more or less assigned the job of keeping everything under cover in order to keep the world safe from Cthulhu (or something along those lines) because if the mundanes found out about the magical world, they would suddenly be a lot more vulnerable to being eaten by star-spawn. Again, or something like that. I haven't read all the Dresden Files books...
There's no overt conspiracy to hide the supernatural world. You even have supernatural factions commissioning books to be written and so forth to leak stuff. Like the White Court vampires supposedly commissioning Dracula to expose the Black Court's weaknesses (not sure if this is mentioned in the books or is behind the scenes stuff from the author or something). Or minor gods/fairies who gain power based on how much worship they have. Or deliberately disseminating information about rituals because the more people try to use them, the less potent they become (the beings who power those rituals can only empower so many at a time).
Mostly secrecy is a combination of magic fucking up advanced electronics (meaning its hard to get good recordings of the supernatural) and people not believing it/rationalizing it away/being in denial.
The one hard and fast (sort of) rule seems to be not to bring mortal authorities into a supernatural conflict. As I recall, Dresden describes that at one point as being their world's version of using nuclear weapons. This being due to the number of mortals, at least in part.
Some do sort of cheat on it, though. The White Court has plenty of contacts in mortal government, ditto John Marcone's criminal organization.
Edit: Their was a more narrow cover up mentioned in the series, though, when the White Council hunted down all the copies of Kemmler's books and destroyed them. Kemmler being a major necromancer who in-universe helped orchestrate WWI before being killed (multiple times) by the White Council.