Unreliable Expositor

""How amusing. [snip] You say that what I'm saying now is a lie -- yet what I said in the past is not?""

- Sosuke Aizen, Bleach

Sometimes, Exposition is put into the mouth of an unreliable figure. The result is an Unreliable Expositor. Frequently invokes From a Certain Point of View, or in-character Did Not Do the Research.

Examples should be confined to exposition that is later proved to be flat out wrong, exposition from somebody later proven to be a lying liar who lies or much much less knowledgeable than they claim to be, or Did Not Do the Research-level science in the mouth of somebody who either is willfully simplifying or is a liar, fanatic, or otherwise fundamentally unreliable.

Related to, but separate from Unreliable Narrator, as the Unreliable Narrator is the storyteller; the Unreliable Expositor is merely providing exposition. Similarly, Mission Control Is Off Its Meds is closely related and may overlap with this trope, but concerns unreliable advice rather than unreliable exposition. May overlap with Motivational Lie.

Anime and Manga

 * Darker than Black provides a healthy dose of Expospeak early on, from a scientist who studies things that are under The Masquerade, no less. The next thing we see? Our expo-speaker did not even knew and presumably was not allowed to have any really sensitive information at all. So, have a happy dish of common oversimplifications and tampered memories. You're on your own. Hell, 90% of everything anyone says in the first two episodes is misleading at best, and Blatant Lies at worst. We're looking at you, Hei.
 * As seen in the page quote, half the things Sosuke Aizen of Bleach says are lies. The other half are half-truths and A God Am I BS. Everything he doesn't say is a lie. His power even has the ability to alter all of your perceptions, or, lie. This is a problem, considering that almost everything we learn about the plot comes from that guy.
 * Applied in layers in Naruto, where Itachi provides exposition about himself and, who provides contradicting exposition about Itachi and himself (as well as quite a few other things later on). Given later exposition from people who seem to be reliable , it currently seems that each was telling the truth about each other but lying about themself.
 * Umineko no Naku Koro ni: Beatrice. So much.
 * In FLCL pretty much all of the exposition that Amarao says is false, its unknown if he made it up trying to look cool or if actually believes the things he says. He was right about the robot replacing Kamon. For all we know, everything he says is true, or at least was true the last time he met Haruko. He can't be faulted for having information that's a decade or more out of date.
 * In the Ace Attorney manga, Robin Wolfe invites Phoenix to his house, saying that he's a suspect in killing his employee Eddie Johnson because he had a talk with him about his disrespectful attitude before he committed suicide, and was the last person to speak with him before his death. It then comes to light that he had taken Eddie to the Den of Spiders add restrained him in a chair for three hours, but while Robin claims that he was unaware of Eddie's arachnophobia, his wife Theridia testifies to his knowing about it. Robin's other lies include the claim that Eddie tried to get into a relationship with his daughter Lira but failed (Lira loved Eddie and hates her father for driving him to his death), and that his brother Bobby is "a servant" (not only do the Wolfes not have servants, but Robin keeps Bobby out of sight of guests, thinking him an embarrassment to thefamily name).
 * Itsuki Koizumi in Haruhi Suzumiya. He says so himself.
 * Itsuki Koizumi in Haruhi Suzumiya. He says so himself.

Comic Books

 * In Gotham Central #14, The Joker alludes to his hostage being hidden somewhere with a Time Bomb. The GCPD note this, but are Genre Savvy enough to know they shouldn't discount leads to the contrary since Joker is the "least reliable person on the planet".

Film
""Didn't I tell you not to trust anyone, Dr. Jones?""
 * Star Wars:
 * Obi Wan Kenobi's original statement to Luke about the fate of his father is extremely misleading, and was the former Trope Namer for Half Truth. This makes Obi-Wan very much one of these.
 * An Alternate Character Interpretation of Han Solo's claim the Millennium Falcon "made the Kessel run in less than 12 parsecs." An ACI as far back as the original script. Backed up in that Obi-Wan visibly winces at this line.
 * In Indiana Jones and the Last Crusade, Walter Donovan:


 * In Charlie and the Chocolate Factory, Willy Wonka.
 * In Miracle Mile, Harry receives a phone call from a stranger frantically exclaiming that World War III is beginning. When Harry tries to confirm what he just heard, the caller plays the whole thing off as a prank.

Fan Works

 * In the Metal Gear Solid 3: Snake Eater fan webcomic The Cobra Days, the Fear lies about pretty much everything, including his back story. Considering he starts out as the main expositor for the Sorrow, he really messes with the Sorrow's perception of the unit.
 * In another Metal Gear example, the main expositor,, in the MGS3 Fanfic The Joy of Battle lies to the Cobra Unit from the beginning in order to turn a mission from the American Philosophers into his own mission. He's not the only one. Actually, any exposition or explanation given by ANY character has a 90% chance of being a lie.
 * The books Twilight reads in The Son of the Emperor tend to be biased or simply incorrect about a number of topics. Mostly those concerning Equestria.
 * With Strings Attached has the Fans, who out-and-out lie to the four on many occasions when they're imparting information—and  lies quite frequently to Shag and Varx as well. While   expository lies are apologetically detailed by the other two after he leaves, their own lies never get exposed (though Shag does feel shame about them at the very end of the book, after the four have been returned home). The biggest lie is why the four are on C'hou in the first place; they were actually part of an undergraduate science experiment to gauge their reactions to being sent to another planet, but they're told they were sent there to break the curse on Ketafa.
 * Also, the story of C'hou's history concerning the Vasyn and the gods gets told several times by different people, until Shag and Varx find out the real story and reveal it to George and Ringo. Even  didn't know the truth.

Literature

 * Practically every book by Tom Holt has at least one of these, often several, outrageously contradicting each other.
 * Falling Sideways is probably the worst about this: fortunately it's all sorted out when one character points at the sky causing giant fiery words to appear: Yes, this is the real world, it's all true. Regards, God.
 * Every member of the Discordians in The Illuminatus! Trilogy. Then, once you get used to not believing a damn thing they say, the narration starts proving unreliable. It Culminates in a scene where
 * The entire plot of R.A. Wilson's The Masks of the Illuminati is based on the unreliability of second and third hand exposition.
 * An in-universe example in Good Omens, where  It's implied that this was intentional. "There is a difference between knowing the path and walking the path," and all that.
 * Complicated by the fact that predicting the future for her was "like seeing through a straw", so she didn't get the full picture on things.
 * In The Roman Mysteries, a number of characters state scientific, medical or geographic facts that are inaccurate but correspond to what character in the 1st century AD Rome actually believed.
 * Tomorrow War subverts a Sci-Fi cliché of the infallible Mr. Exposition—it's narrated by a Space Fighter pilot who thought the range of some missiles is limited because their warheads freeze (What? He's a good pilot). Fanon explanation is that while we can be reasonably sure that an engineer making rather "hard" setting knows better than that, this unties the authors' hands in more slippery cases: now they always can write off a few details to mistakes of one Eager Young Space Cadet who slept through a half of his lectures.
 * Done by various people in Warbreaker to the point where it's difficult, even in the end, to tell who's been telling the truth about the origins of the God Kings, the nature of the religious turmoil between Idris and Hallendren, or much concerning biochromatic breath.
 * An entire prologue in the one of Belgariad books is written by Torak, who plays up his role in creating the world, and tries to paint Aldur and the Orb as evil and his theft of the Orb as a noble sacrifice to try to save his brother.
 * Information on the outside world of 1984 all comes from The Party, which by the premise of the book can't be trusted.

Live-Action TV

 * Anytime we get any exposition on Lost about anything related to the Island and its various mysteries, it turns out to be a case of this. Thi is mostly because Ben, one of the people who knows the most about the island, is a lying liar.

Tabletop RPG

 * Forgotten Realms has a lot of this.
 * The "best" case, of course, is Volothamp Geddarm and his "guides" that canonically combine dangerously clever investigations and silly hearsay.
 * Mintiper's Chapbook is a Realmslore textbook on Unreliable Exposition: it consists of short excerpts from verses or tales by Mintiper Moonsilver, long comments by knowledgeable Keeper of the Vault about events in which Mintiper's "or his source's" alias participated and... even longer Chronicler’s Footnotes that explain how some or other Keeper's notions above are flawed due to his bias toward Silverymoon history and realities and unwarranted scepticism regarding the breadth of Mintiper's adventures.
 * The history of High Moor. One pissed-off druid in Elminster's Ecology assumes it to be the result of typical human deforestation. It's the result of a Killing Storm. He just assumed based on what he saw and knows, and probably never saw a single elf capable or willing to do this, nor would know, since elves aren't eager to tell anyone else about less glamorous moments of their past.
 * Also, a two-part article named simply "Trusting in Lore".

Theater

 * Mrs. Lovett from Sweeney Todd: The Demon Barber of Fleet Street is definitely one of these. The news about his wife's rape and his daughter's adoption by Judge Turpin were most definitely true, but the same cannot be said about . Sweeney only learns the truth after he, and needless to say, he is not happy.

Video Games

 * Knights of the Old Republic II gives us Kreia, who lies. She lies a lot. Considering she is your main source of exposition, this poses something of a problem.
 * Knights of the Old Republic has a much smaller example. On the unknown planet near the end of the game, one can find two tribes of Rakata who have retained the history of their race to some extent. But while one of these tribes kept their history stored in databases, the other is essentially a primitive tribe with only vague and legendary stories about their history, handed down orally over the course of 25,000+ years. Needless to say, the history they keep is somewhat less than reliable.
 * The Codex of Mass Effect. While it has a wealth of information that provides good background information on The Verse, certain details sometimes contradict what the player has seen or done.
 * The best example of this may be in Mass Effect 2 where the entry for "Reapers" claims they are nothing more than a superstitious myth. The players know better.
 * The Codex of Dragon Age has entries on a myriad of topics written by people in-universe. How true the entries are... varies.
 * Planescape: Torment "Don't trust the skull!"—the one that appears at the beginning of the game and remains mostly throughout, feeding you information.
 * This is sort of a selling point for The Elder Scrolls series. There is no true canon except what happens during the game, and every person or book's version of the backstory (of which there are several, backstories and versions that is) has to be taken with a grain of salt. Essentially, the only information you learn about the game world is the stuff you could learn by actually being there, even recent history. Combine this with the depth of the world itself and the number of different overlapping mythologies and cultures in said world, and you wind up with a lot of really damn weird discussions on the forums with cosmological debates rivaling those of, well, the real world. Vivec embodies this trope, being a self-professed pathological liar and implied madman who provides most of the series' cosmology.
 * One chronicle that is completely reliable would be an Elder Scroll itself. The Scrolls are completely irrefutable due to their close link to reality itself; their power transcends even the gods. The only problem is that it could also end up showing you what could have happened if you don't read them right (though that information could be of use too).
 * Psychonauts, being a game that takes place mostly inside people's minds, brings this up at times, though a little digging makes the real stories clear. Notable are Gloria's biographical "plays" (a bit warped by her own point of view of her childhood), Edgar's wife (a deliberate romanticization), and Coach Oleander's memories of the military.
 * Portal.
 * A bad case occurs in Higurashi no Naku Koro ni where often even the unreliable expositors don't realize what they're saying is nonsense, or it's completely irrelevant or even just misleading. After all, the characters are trying to work out what's going on at the same time as the reader. Apart from not knowing whether their conclusions are correct, a lot of the time characters are going crazy or getting paranoid.
 * This is par for the course in all Metal Gear games. The person who gives you your first bit of exposition is more than likely trying to manipulate you into doing something you'll regret by the end of the game. The in Metal Gear Solid 2: Sons of Liberty is an example of an unreliable expositor where, in the end, you still don't know what the truth was.
 * Early on in Last Scenario, most of the exposition about the overall plot comes from Zawu, a mysterious woman who shows up out of nowhere one day to tell the main character he has a great destiny. As the story continues, her motives start getting called into doubt; ultimately it's revealed that
 * Somewhat similar to the above Elder Scrolls example is The Legend of Zelda. As it is, really, a legend, the events of each game have faded into myth by the time of chronologically later games, so in any given game the exposition about what happened previously is as heavily corrupted and confused as any real-world legend, and every game will inevitably delve heavily into the in-universe legends about what happened last time in the chronic Vicious Cycle. This can lead to massive player confusion when they make a prequel about those previous events, and they turn out to be not very much like what legend remembers them as at all.
 * This is also why the fandom's attempts at creating a coherent timeline (or two, or three) out of the series have failed.

Western Animation

 * Batman Beyond has an interesting, possibly unintentional, case: One character claims that psychic powers are a result of being able to use the remaining 90% of Your Brain; but that character is an avowed Psychic Supremacist criminal foot soldier (in other words, exactly the wrong person to be giving scientific exposition).
 * Likewise in Justice League Unlimited, when Amanda Waller claims Cadmus was made purely in response to the Alternate Universe where the Justice Lords conquered the Earth. At least two creations of Cadmus, Doomsday and the metahumans who would become the Royal Flush Gang, predate contact with the Justice Lords' universe which indicates either a continuity error or Waller lying about how old the organization was. It's later implied that it was actually in response to Superman being brainwashed by Darkseid two series earlier.
 * In The Boondocks, Grandad's stories about his life experiences are often questionable and he tends to lie to try to get out of just about anything.
 * In The Legend of Korra, Amon turns out to be this, though this should come as no surprise given the historical precedent of charismatic radicals fabricating their origin stories.