Rosario + Vampire has Koe the bat, who narrates to the audience, as well as acting as a censor by flying between the camera and any inappropriate shots - no one knows who he keeps talking to all the time.
Love Hina: Has Mutsumi and Su doing this from time to time, For example:
Mutsumi talking to Naru about a letter from Keitaro
"Don't you remember…I told you about it just a few pages ago."
Su talking to Keitaro about his broke leg.
"Can't ya just put a band aid on it and make it better in the next scene like ya normally do?"
The anime only Kentaro. Originally The Rival, morphed into something of a personified Deus ex Machina, who makes some comment about the narrative he points at the subtitles when Naru gets his name wrong.
"Well. I suppose that's all the screen time I'm getting this time."
Many tankobon volumes of manga (ie, any individual-series manga you'd pick up in a shop) have additional sketches or comments from the author between chapters. Some of these are just random blurbs of information about the author and what went on when making the series, others fall into this, bordering into No Fourth Wall territory. A particular set of examples in several of the tankoban volumes of Fruits Basket are single-panel reactions from characters stating their disdain at not being featured as prominently in that particular volume, with another talking about the one with the most focus, or whoever's on the cover. Some go as far as to have the characters actually holding the very book themselves.
In AnotherHOLiC, the ;;Xxx HO Li C;; story written by Nisio Isin, Yuuko Ichihara says that something is "most vexexing". When Watanuki asks if she just stuttered, she replies "No. Merely a typo."
Jessie, James and Meowth in Pokémon, particularly in the English dub, frequently reference the writers, the artists, the audience, the half-hour time slot, and the fact that they're in a "cartoon"—and if they're in a movie, they're sure to appreciate being "on the big screen". None of the other characters seem to notice this.
Or do they?
Jessie: Prepare for trouble like you've never seen!
James: And make it double, we're on the big screen!
Ash: I'll have to catch this on video!
TR: GAH! (near-face fault)
Nah, he was just being Very Punny with their new motto.
Ajimu of Medaka Box is fully aware she's in a manga and even tries to end it before the beginning of the anime adaptation by defeating the main character with another supporting character. Everyone just thinks she's crazy. Kumagawa seems like this, but he has simply read a ton of manga himself.
Deadpool of Marvel Comics is known for being able to see through the fourth wall and snap it in two if he wants to. The reasoning is because he's a very special kind of insane, which occasionally allows him to perceive things others cannot. From being able to see the yellow boxes that he thinks in, to referring to the last time he showed up by issue number, Deadpool's odd observations are even occasionally plot points; for example, Deadpool is unaffected by Marvel's recent massive retcon of the past twenty years of Spider-Man's history, leaving some fans to speculate it was put there as an editorial escape plan if necessary.
Likewise She-Hulk is known for knowing about the fourth wall. She has arguments with editors and artists, has at least one time used panels to win a fight or skip over boring parts of a story, and has complained about advertisements or used them to her advantage.
Unfortunately, with Marvel becoming Darker and Edgier by the minute, she's seen doing this less and less.
The current excuse for removing this aspect of her character is that She-Hulk is no longer aware of the fourth wall, and has forgotten all these instances of knowing about it. The times when she was, have been explained away as a "side-effect of her gamma-irradiation" which caused her to see things that may not have been there. Lyra has revealed she also has a perception change ability, but instead of seeing the fourth wall, she sees all gamma particles when in a meditative state.
Also, think about it a little bit; if She-Hulk knows about the Fourth Wall, doesn't that kind of make Deadpool less special? (Squirrel Girl below is okay; she's obscure enough not to form a problem)
According to some sources, she still has the ability but just lets Deadpool have fun with it instead.
When Deadpool and Squirrel Girl team up in a GLA special, the Fourth Wall doesn't so much break as slink away quietly with its tail between its legs. Rather than explain to her in detail what happened to her boyfriend Speedball, Deadpool just hands a copy of the relevant comic to Squirrel Girl and lets her read it.
Most of the characters written by Fabian Nicieza become Fourth Wall Observers during the recap pages. They are allowed to, because the recap pages are not in continuity (a clause even Deadpool is forced to follow).
Which doesn't prevent him from, in the story, wishing that the recap page were in continuity so he might have a clue about what the hell was going on.
Amazingly, these recap pages are in continuity for Squirrel Girl.
While The Joker is occasionally like this in normal comics as well, in the Emperor Joker storyline, where he gains 99% of Mr. Mxyzptlk's powers, he becomes one of these big time, occasionally making references to the comic and the industry, which the other characters usually ignore. Among the best of these that he did was sticking a "Why Didn't Anyone Call In To Save Me" sign on Jason Todd's skeleton (a reference to the fact that DC used a phone-in poll to decide whether he would live or die), and, faced with the fact that he couldn't erase Batman from existence due to his obsessions, yells at the artist to stop redrawing him.
Mxyzptlk himself is Fourth Wall Savvy. In a recent issue of Superman/Batman:
"I wanted you all to have a little more fun. And to sell a whole bunch of issues."
He's lost the fourth-wall breaking with his current incarnation in the New 52, apart from the odd Continuity Nod referencing Morrison's defining run.
In a Simpsons Comics Hallowe'en story, after multiple alien invasions and random people spending several panels ranting about conspiracy theories, Sideshow Bob turns up to tell the Truth — they're "all merely pen and ink creations trapped in a juvenile comic book!" He gets laughed at at first, but proves his case by pointing out the comic book panels and then forcing everyone to look at the reader.
The Incredible Hulk used to pal around with a group of super-powered do-gooders called The Pantheon. Except Paris wasn't quite the do-gooder they thought. In addition to causing outright chaos, he speaks to the reader, is aware when the end of the book is coming up and at one point, turns the book OFF. Creepy.
In issue 66 of Alpha Flight, Whitman Knapp becomes one of these for the length of the issue, treating the writer with sarcasm. It turns out to be a delusion created by the Dreamqueen.
Again with the Hulk. Rick Jones, long-time superhero sidekick, has developed 'comics awareness' as detailed in 'Captain Marvel #60'. He does not seem fully aware he is in a comic book, but he can clearly see the forest for the trees. Years of dealing with cosmic beings who can rewrite reality on a whim has made him the most genre-savvy of the entire Marvel Universe. He recognizes when it is time for the wacky adventures to stop for now. It's not perfect, mind, he accepts the comforting delusion that his wife had a pleasing lesbian affair due to telepathic influence, not because she was bi and the marriage was on the rocks.
Flint Dartson of A Loonatic's Tale is renowned for constantly breaking the fourth wall. While he may not make it known to the other characters, he continually acts knowing that there is a script and author causing the events around them.
An interesting case in Supergod in which the Dajjal was talking out loud while the narrator was also making an Apocalyptic Log. Since he is The Omniscient, then he is probably aware of the fourth wall.
The Marvel Comics finale of Mighty Mouse has this all over the place. It starts with the action stopped after the first page as Pearl Pureheart boycotts the rest of the issue because comedian Andrew "Mice" Clay was appearing (a nod to Nora Dunne refusing to appear on Saturday Night Live because Andrew "Dice" Clay was appearing).
The Grim Adventures of Billy & Mandy story "Future Tense" (Cartoon Network Block Party #36) has Grim saying he can use his scythe to find out what Nostradamus is saying about his future, with Mandy finding it too convenient: "Doesn't this comic have any standards?" she asks.
Although most characters saw the 4th wall in the Sonic The Hedgehog series, they seemed to have lost this ability when the comic's genre shifted. However, Bean the Duck continues to break the wall.
Genie from Disney's Aladdin is one of these; though his insights usually have more to do with real world events, celebrities, and popular characters than actually referencing the fourth wall, he still has the same effect on the other characters. The cartoon series discusses this at one point, where Aladdin explains to Jasmine that Genie is just referencing things that don't exist yet, and basically admits that he just ignores him when he does this.
Stranger Than Fiction is an interesting variation. The main character can hear the narrator and recognizes a sort of fourth wall, but the narrator is actually someone in his world whose writing dictates his life. In fact, they eventually meet.
In a Finnish comedy film from the Uuno Turhapuro series, a waiter has been tricked, by two alcoholics, into drinking a full bottle of vodka. Later, when a lady enters the restaurant, and listens to the waiter singing a song, she glances around, and declares with an enlightened face: "I see. This must be a Finnish movie. There's no other explanation for the presence of so many drunkards in one scene."
The titular character becomes this after returning to his fictional life at the end of Last Action Hero.
And in Spaceballs, Helmet finds out where the heroes escaped to... by watching Spaceballs. This includes fast-forwarding past the embarrassing scenes that happened to the bad guys, and accidentally finding the scene where they are watching Spaceballs, causing a very confusing conversation about defining the concept of "now".
Similar to the Men in Tights example noted above, in The Muppet Movie, Kermit and Fozzie give the Electric Mayhem a copy of the movie's script rather than explain the entire backstory of their trip. This allows their new friends to learn what's going on while Kermit and Fozzie take a much-needed nap - and later in the film, it allows them to track down the lost frog and bear because they recognize the description of the current scene.
Ferris Bueller from Ferris Bueller's Day Off regularly comments directly to the audience about the film's plot, about the other characters, about being in High School, and so on. At the end of the film, after the credits, he even says to the audience, "You're still here? The movie's over! Go home!"
Groucho Marx of The Marx Brothers incorporated this into almost all of his movie roles. It's one of the traits he passed on to Bugs Bunny.
Groucho(looking out at the theater):"I may be stuck here, but there's no reason you can't go out into the lobby until this all blows over."
Susan: ...Do you think we might be in a children's book?
Ed: Of course we are, if you look down you can see the page numbers.
A similar thing happens with Bromosel in Bored of the Rings, after it has been foretold that he'll die sometime "around page eighty-eight." None of the others seem to understand this, but whenever they get into dangerous situations, Bromosel is mentioned as taking a quick glance at the page number.
In the superhero novel The Silver Seven the character Timothy Wonder looks directly at the fourth wall on numerous occasions, calls out tropes as they are played, but still demonstrates a complete lack of Genre Savvy.
One of the Reminiscences of Ijon Tichy from Memoirs of a Space Traveller by Stanislaw Lem is about a scientist that succeeds in creating sentient AI in the form of computer-generated phantoms living in a digital world. One of this beings is aware of how things are (or rather foreknows it), and is held by the others as a madman. It is suggested in the story that its characters may well be in the same situation.
Live Action TV
In one of the later seasons of the X-Files a movie producer witnesses a skeleton assemble itself and walk/dance around the room. When talking about it later on he says: "It was either animatronics or CGI." For the record it was the latter.
Originally, Denny Crane was the only one who knew that Boston Legal was a TV show. In later seasons other characters, particularly Jerry Espenson, start to notice as well.
If Abed on Community had a job description (other than "student"), it would be "Fourth Wall Observer." He believes the world to be like TV, and because he's a character in a TV show, it is. He can even predict the future thanks to his knowledge of tropes. Heaven knows why he doesn't have a handle here.
Abed does break the Fourth Wall occasionally. In one episode opening skit, the other characters ask him if he can stop acting like everything is a TV show. His reply? "That's kind of my gimmick... but we did lean on that pretty hard last week, so I guess I can lay low for an episode." He has no further lines that episode. And, yes, the previous episode had been particularly Abed-heavy.
This gets even better when Jeff starts to understand Abed's way of thinking a little bit after some time, slightly becoming a Meta Guy himself. More frequently referring to 'seasons' and 'episodes' as well.
This is ultimately deconstructed. Abed doesn't truly believe he's in a TV show, he just has great difficulty understanding the world around him. Framing his life as a TV show makes it easier for him to understand, and is sort of a coping mechanism of his. When his life temporarily turned into a mafia parody, he dropped the meta shtick as reality then made perfect sense to him and didn't need a framing device.
In the Til Death episode "Hi Def TV", the character Doug spends whatever screen time he has being the Fourth Wall Observer. He is suddenly fully aware of when the camera is on him, that their food is from brands that don't exist, convenient plot elements, censors, the laugh tracks, that all the rooms have only three walls and there is no such thing as a second floor. He is even unfortunate enough to catch a glimpse of one of the mics. Needless to say all the other characters think he's a little off his rocker.
Effy from Skins does this quite often, most noticeably in the final shot of the finale of series two.
Played with in The Muppet Show, which was sort of a Show Within a Show. The "outer" show's fourth wall remained largely intact, while Waldorf and Stadtler (aka "The two old guys in the balcony") were this to the "inner" show.
In a recent episode of How I Met Your Mother, where Marshall and Lily hold a game show to decide which of their friends is to be the guardian/godparent of their newborn child, Marshall gives the opening narration of the show to the camera. Ted asks him who he's talking to.
There were times on Green Acres when Lisa Douglas couldn't sleep because she could see the credits. Oliver never saw them.
MythQuest: In-universe whenever Alex or Cleo travel into a myth. Also Gorgos, who knows he's in a myth.
There's a hilarious sketch in A Bit Of Fry and Laurie, where Fry and Laurie are policemen looking for a criminal. At one point Laurie, caught up in his speech to the woman present, walks off the living room set and past one of the cameras. When he realizes what he's done, he then casually strolls back on, never breaking character or stopping the sketch.
The main character in the US version of 'House of Cards' regularly soliloquises directly into the camera's lens, often to inform the viewer of his deceptive behaviour.
The Burns And Allen Show: In the TV series, George addressed the camera in every episode. In the live episodes (the first two seasons), George addressed the camera and the theater audience. In the filmed episodes over the remainder of the series, George not only addressed the camera, he also had a TV in a den that allowed him to watch the other characters in the show.
WWE's Triple H holds the crown of fourth-wall breaking. From hinting at his Real Life marriage to Stephanie McMahon to cracking jokes about the referees, the sound crew, the cameramen, and how the heel / babyface relationship works. Some of his more humorous examples are:
To an audience at a Raw taping: "And for the millions, who, five minutes ago, were watching at home. (crowd boos) Oh, come on! It's like, 11:08, guys, we're off the air!"
After a microphone malfunctions at a press conference: "Crack sound team we got here. Where'd you buy these things, Wal-Mart? I think we're gonna be auctioning them off later, you might wanna get a receipt."
To Shelton Benjamin, coming down the ramp during an episode of Smackdown: "Shelton man, stop right there. That's not how this works. See, I'm doing what we call a 'promo' (does air quotes). In this 'promo', I'm gonna stand here and talk about how I'm gonna beat you in our match. And then you're playing what we call a Heel, you've gotta wait till my back is turned and then sneak up on me. That's how this works."
To Vince McMahon off of Vince's outraged "What are you doing here?", after first waiting several minutes for the crowd to stop cheering: "I'm waiting for this pop to die down, man, did you hear that?"
The whole "Cm Punk will leave the company with the title" story has kind of turned Punk into a fourth wall observer. Every story connected to it revolved around real life issues. Its very evident when punk had promos with Cena because theres an obvious contrast when Punk is talking about the stuff that make all the smarks cheer their heads off while Cena stays totally in character and treats Punk like the evil Heel
The MLB: The Show series does an admirable job making its in-game presentation as if it were a TV broadcast, but occasionally, the commentators will break the fourth wall. During a cutscene of a frustrated pitcher, Rex Hudler will comment that "he's using words we can't use in the video game!". And if you get a generous call at the plate as the year's cover athlete, Dave Campbell will remark, "See, that's the kind of call you get when they put you on the cover on the game." Conversely, if Roy Halladay (opposing franchise MLB 2K11's cover boy) has a bad call go against him, Campbell will opine that Halladay would have gotten the call if he was on their cover.
In Dead Rising 2, player character Chuck Greene, always says something relevant when you have him put on new clothes. Get him to crossdress, and he'll express discomfort, saying things like "Um...Seriously?", "Uh..." "If you say so..." and "I got a bad feeling about this." These seem to be his only moments.
If a certain bartender in RuneScape is asked where a brave adventurer might find her or his fortune, he fears that giving away hints will make the 'computer game' too easy. One of the options on the resulting dialogue tree triggers an amusing conversation in which the bartender attempts to explain things by heavily breaking the fourth wall, only for the player character to give up and tell him that he is obviously mad.
In Max Payne, an unknown person turns Max into a Fourth Wall Observer. During one of Max's hallucinations on the drug V, he is told by an unknown person that he is in a graphic novel (what the cutscenes are presented as). He instantly relizes that his life is all fragmented still shots and the fact that he can see his thoughts and words hanging in thought/speech bubbles in the air. The same voice then tells him that he's in a computer game. Once again, he instantly sees "weapon statistics hanging in the air, endless repetition of the act of shooting, time slowing down to show off my moves, the feel that someone is controlling my every step."
In Rogue Galaxy: All the characters have flavor lines they say as you move around. These lines might change given where you are, and what events are unlocked. Well... Kisala, when you play for longer than a certain amount of time without saving (or defeating a few bosses also seems to trigger it) she says something along the lines of "shouldn't you get to a save point?" And if you play more than 3 hours or so, "You've been playing a really long time! Aren't you tired?"
"You've been playing forever. Why don't you call it a day."
Every World of Warcraft player character, and I'm not referring to chat and player controlled actions, eg "Not Enough Rage".
Travis Touchdown of the No More Heroes series fits this well. He says a lot of things that imply he's aware he's in a videogame, like telling the player what button to press to start the game. He even speaks to the player during a sum up scene of him explaining how he got into this mess in the first place.
A scientist in the Starcraft universe holds a theory that they are all nothing but units in a computer game obeying some greater entity's whims. Naturally, she is mocked by everyone else.
In Dragon Age II, a patron at the Hanged Man frequently comments on various aspects of the game and openly wonders if he's just a character in a story that someone else is telling... and why he couldn't have been made more attractive.
Secret of Evermore has a ranting prophet in the city of Nobilia. He declares his entire universe to be at the control of a "button-pressing overlord" and eventually gives you the option to transform him into one of several objects. If the player cancels out of the dialog, he thanks you (the player) for not polymorphing him and gives your character an item.
Psycho Mantis from Metal Gear Solid may be one of the most famous examples. He knows how many times you've saved, reads your memory card and comments if specific games are on it, makes your controller move "with his own mind".
The dwarf sidekick in Save the Prince is very much aware of the fact that he's in a game. When the main character Giselle asked what he was doing at the start of one level he said he was consulting the strategy guide, and when she asked if they were still a long way from the castle toward the beginning of the game he replied that they were only on level nine.
Blazblue: "Don't worry. You're friend on the other side of the screen will remember all this."
The  series takes this trope and goes to town with it.
Com'c: Block is a professional wall breaker specializing in walls labeled "4". He doesn't fit the "not believed by anyone else" part of the trope, however, because the author has made him unnoticable to the characters with an intact Fourth Wall.
It seems this isn't a problem with Nope Guy - NG has been shown to interact with both Block and the main characters, which may indicate that he is also an example of this trope.note Even the author doesn't know if he is or not.
Cherry from RPG World is quasi-Fourth Wall Savvy. She keeps questioning the tropes of the game in which they exist.
Drowtales: Kiel "has an imaginary friend who just happens to be wherever the camera is." Said friends — and by extension the readers — are actually the demonic taint itself.
In The Order of the Stick, all of the characters show Medium Awareness and huge amounts of Genre Savvy, but Elan generally shows more than the rest, but not necessarily knowledge of the fourth wall more than the rest (as the characters consider the fourth wall more part of the sets of rules for their universe, and rarely ever directly break it as much as reference it). However, the Oracle does show complete omniscience in that regard, talking to the audience as well as the general Medium Awareness the characters show, and gets the same reactions as most of these examples, thus, he is one of these relative to the rest of the characters, even though the other characters show bits of No Fourth Wall themselves. This has extended as far as borrowing things from themselves in other places on the site, with the artwork for those places being contemporaneously updated to reflect the change.
Think of it this way: Most of the characters have a jackhammer with which to dig a hole (size varies with the character) through the Fourth Wall, through which they can look at and interact with our world. The Oracle? He gets an Earthmover, and is very well acquainted with the controls.
In particular, the demon roaches who are always loitering around can break the fourth wall at will, and do so at every possible opportunity.
Tea, the white-haired girl in Gunnerkrigg Court, appears in some between-chapter bonus pages to talk directly to the reader. Since author Tom Siddell has stated that all strips (except for the one in which he himself appears alongside Tea) are Canon, it can be deduced that Tea has the power to see our world and know about her own world's true nature.
Erin from Dragon City pretty much knows it's there. The rest of her family is quasi-aware of it because she often gets in trouble for breaking the fourth wall, but for the most part, everyone else pretends they don't know.
The Sidereal fate-ninja Nemen Yi dodges attacks by jumping between panels and utilizes skewed perspective to do things that should be impossible (such as slashing three people standing ten feet apart with a single strike). On one page she even breaks off part of the nearest frame and uses it as an Improvised Weapon, which other characters still cannot see. (In Exalted, Sidereals can see and manipulate Fate in a way no other human can.) However, she does not acknowledge the audience.
The Fair Folk take this to the next level: They're fully aware that they exist in a webcomic, and in fact attack the party solely because they wouldn't exist otherwise. They also operate the Fourth Wall Mail Slot, bringing letters to other characters who have no clue who sent them. Of course, the humans think they're insane. All this is perfect, because in ExaltedThe Fair Folk very much treat themselves, each other, and Creation as fiction and story-telling, and they've even been compared to role-players.
''Magellan features the cult of murderers called the Character Assasins, who assasinate people seemingly indiscriminately. Their leader believes they are all characters in a fictional world, and that by finding and killing the "Alpha Character", they can take control of the creator. All characters in the world treat him like a loony, but in a way he's Properly Paranoid (though assuming the "Alpha Character" is the protagonist, he did get the wrong one). Naturally, he breaks the fourth wall during his rants.
Everyone in Webcomic/1/0
One Dr. Rioghail of the SCP Foundation went mad, believing he was coming up with SC Ps, writing reports on them, and submitting them to the SCP database for review.
In what has got to be a consolation for the above, in the Weisman-run The Spectacular Spiderman, the Green Goblin was shown to see through the fourth wall on occasion, and in one instance of this, quotes/paraphrases lines from Puck in A Midsummer Night's Dream.
In the Adventure Time episode "Beyond This Earthly Realm", Ice King is hinted to be this as he stares into the static on Finn and Jake's TV set (and eventually at the audience) while rambling:
Ice King: Whaddaya think, Finn? Can we pull back the veil of static and reach into the source of all being? Behind this curtain of patterns, this random pattern generator... so clever, right here in every home, watching us from a one-sided mirror... (realizes Finn is staring at him) Heh heh, whoops! Just wizard-talking to myself!
Megavolt in "Darkwing Duck". Let me count the ways: complaining that the show's theme song is stuck in his head, observing that the "frequency fiend" monsters could return if they obtained a part from a standard television set, momentarily thinking himself to be the villain of Scooby-Doo (before correcting himself: "Wrong cartoon!"), and, to take the cake, inventing an in-universe device that teleports him and Darkwing to a world where they're only a cartoon—in other words, our world.
Angelo Rules: Angelo is fully aware of the camera and often talks to the audience as if were one of his friends joining him wherever he goes.
Alaina (Angelo's sister): (ranting about fashion)
Angelo: (turns to look at us) "I'll spare you the next 5 minutes." ("fast forward" icon appears next of him and the scene speeds up until they get the mall at which point a "play" icon appears and he gives the viewer a "You're welcome" look)
There is a variant of paranoid schizophrenia now named "Truman syndrome", in which the patient believes that their lives are actually a television show. This may be the best and most controversial example of Defictionalizationever.
John Carmack, in a similar vein to the X-Files example above, after decades of designing game engines, could apparently look at anything in real life and determine what type of CG technology was being used to render it.
Having computer graphics as a hobby has a similar effect, only the results are geared more towards being able to tell what primitives and texture components you'd need to recreate what you see in the computer.
Anyone who has a lucid dream. For those who don't know what they are, in a nutshell, they're dreams that you're aware they're dreams whilst having them. Exactly how aware you are of them being dreams vary, though.
With enough awareness, you can take full control as a Reality Warper or will yourself awake.
Religions are big on this. When it gets right down to it, prayer is begging the author for a happy ending.
Physics. Especially quantum physics, where the scientists observe how weird the underlying rules of reality can get.