One canon that knows about us is The Puppet from FNaF, on the basis that it has power over life and death. Seeing as Death itself and its various avatars know about us, the Puppet was given the same honor. (Probably due to the fact that aside from being able to stuff spirits into animal suits, we have no clue what the Puppet is capable of, so he's put there just in case. At least, that's my theory.)

Another one would most likely be Hermaeus Mor from Skyrim. Seeing as he's the daedric lord of knowledge and memory, I doubt neuralyzers will affect him.

Also, the Outsider from Dishonered may qualify as well: given that he's said to be all-powerful on many, many occasions in the game, he definitely fits.

I do believe they should be more special then your regular canon character. After all, the knowledge of the fact they are in a fictional story is important. However, this does not mean they should be aware of the PPC. So, what to do? I say, make them able to see agents, but not know who they are. Canon helps to cloak the agents from the average canon character, unless they make themselves known. However, because of the interesting nature of fourth-wall breakers, this cloak fails to hide the agents from those who can already see far more then they should.

What does this mean? That Deadpool will always harass any agent in the Marvel cannon? Well, no. He likely would not care about them. And not because of the SEP field (which I am on record for thinking as cheating, and am not a fan of their usage in missions) but because, well, why would he? Does he interact with literally every single person milling about the local block? Well, sometimes, but that's besides the point. Unless the agents are in a conspicuous location that he is clearing out, say something that would be funny of he were to interject, or otherwise draw his attention, he's likely to notice them and just move on. Why do you think agents have disguises? Here you go.

What does this change? Unless the author wants it to, not much. It opens up an avenue for character interaction and agent danger, while not necessitating a interaction if the mission writer does not want to be bothered.

The one exception to this (that I can think of) is Pinkie Pie. Not that she should know about the PPC, mind you, but that she would force an interaction on you if you are in Ponyville. She knows everypony in town. Everypony. And if you're new in town, she will make sure to give you a big welcome. And yes, this would include folks under SEP fields. New ponies in town are her problem. Always. How can you justify not having a surprise party forced on your agents every time they enter Ponyville? Well, for one, have the agents be careful. Two, she may not fully recognize them, but something tells her that it would be a really bad idea if she were to bother the new ponies right now. She may leave a small gift for them instead. Third, there is something very familiar about return agents...

Just my thoughts. It makes fourth wall characters a little more interesting, without making PPC knowledge a badge of being *specul*.

Don't introduce them unless you have a really good reason. They're a lot of headache. If possible, Hand Wave around them.

The following points include mild spoilers/speculatons about the Dresden Files and Persona. You have been warned.

For characters indoubtly in the know about PPC inside the DFs, there is one I would like to have an opinion about, The Archive, Ivy during the main series.

The Archive is a woman who holds inside her mind a perfect copy of any information ever written, plus the memories of the preceding Archives, and who in the past, could play the Pythie of Delph thanks to this knowledge.

I think she would be in the know because anything written means the charges lists. Now, you could say "Don't write anything then.", and you're right (It's even the 1488th thing not allowed to do inside PPC.). Te catch? It also means the canon material necessary to exorcisms, and once even one book is brought inside this world, she would know about this (And with the slash you can find about Dresden and mafioso Marcone, you bet that exorcisms are in sore need here.) . Now, the Archive can 'delete' an information from her mind once it's the only place where it's left, but couldn't she keeping PPC awareness from this experience?

My other question isn't about canons in the knows, but who could be able to see through SEP Fields and would know if they're faced with a glitterbag: Igor and the Velvet Room attendants inside said Velvet Room.

Gameplay-wise it's a hub where you can fuse new Personae, check Social Links progress... Lorewise, it's a construct inside the Collective Unconscious, manned by Igor, servant of Philemon, supposed to be the embodiement of any good inside mankind (check Jung for more information), and the attendants, other beings from this other world.

Now, the VR is a place who, judging from the implications in-game, exists within the main of the Persona Users linked to Philemon (Persona 1 and 2), or whoever inherited the Wild Card power and passed a 'contract' with Philemon (Persona 3 and 4, for now.).

Now, they also seem to know anyhing about the people(s) linked to the Velvet Room, so the intrusion of a glitterbag would rise their eyebrows. Not only that, but they also say something without a complete psyche cannot enter the VR, and they're aware of the mind of any person entering, and since glitterbags were always stated to be less than complete on that matter, they'll see them as something closer to Shadows than anything else.

Now, it doesn't mean PPC knowledge, but in my opinion, it means no SEP Fields inside this room, and necessity to neuralize Igor and the attendants every single time. Am I right?

Last note, what's would be your opinions about the 'gods' inside the Collective Unconscious, beings like Philemon, no actual gods, but enbodiement of some type of thoughts from mankind, like grief, desire to die...