%% Image selected per Image Pickin' thread: http://tvtropes.org/pmwiki/posts.php?discussion=1333805575046662500
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[[quoteright:300:[[Manga/DeathNote http://static.tvtropes.org/pmwiki/pub/images/rsz_death-note-89715_6157.jpg]]]]
[[caption-width-right:300: It's short for Laura.]]

->''"You may want to add a few more vowels into your name there, ''Z''."''
-->-- '''Sebastian Stark''', ''Series/{{Shark}}''

When you take OnlyOneName to the extreme, this is the result. Most often a CodeName.

For some reason letters from the second half of the alphabet are much more likely to be chosen. Even people who change their names to something starting with A to get to the top of an alphabetical list seem to never use just A.

A fair number of older novels (from, say, the 19th and early 20th centuries) use this as a form of "discretion shot". (See SpellMyNameWithABlank.) For example, a lot of Sherlock Holmes stories refer to "Mr. B----" as a way to imply that this is a real person and the story really happened in the real world, but that due to the potentially embarrassing nature of the events Watson is too much of a gentleman to reveal Mr. B's true identity.

Compare YouAreNumberSix, when the name is a number. JustForFun/NotToBeConfusedWith OneLetterTitle.



[[folder:Anime & Manga]]
* A serial killer in ''Manga/HellTeacherNube'' that patterns himself after Aka Manto (Red Mantle) is simply referred to by authorities as "A". It's clear this is an attributed alias, but we never learn his real name.
* ''Manga/IWish'' has the male protagonist called K. It's stated early on that he goes by K, because his real name is cursed.
* Count D and his relatives in ''Manga/PetShopOfHorrors''.
* D, the alien spy from ''Anime/ProjectAKo''. It is, however, a code name.
* D from ''Anime/DualParallelTroubleAdventure''.
* The title character of ''Anime/TekkamanBlade'' is nicknamed D-boy. In the OVA, he has taken to signing his name "D", and Yumi simply calls him that. (It's actually "Dangerous", for doing a lot of reckless things early in the series.)
* The title character of ''LightNovel/VampireHunterD''.
* ''Anime/YuGiOhGX'':
** In the English dub, Aster Phoenix's adoptive father is named [[SpellMyNameWithAThe The D]]. In the Japanese version, he was called DD, [[CaptainObvious which is a two-letter name]], but comes close.
** In the Japanese version, the Deck Destruction pro-duelist is named X. In the English dub, he was called Howard X. Miller.
* G, the BigBad of ''Manga/RealBoutHighSchool'', who honestly doesn't remember his name after the years of psychological and physical conditioning he was subjected to since he was a boy in order to become the perfect bodyguard. As far as he's concerned, it's a placeholder; He'll find out what his name is if it's the last thing he does. [[ShoutOut Like many characters in the series]], G is a CaptainErsatz of a ''[[VideoGame/TheKingOfFighters King of Fighters]]'' character; in his case, K' (see below).
* G., the first Vongola Storm Guardian from ''Manga/KatekyoHitmanReborn''.
* Phantom Thief G? from ''D.Gray-Man''
* Soldat J, from ''Anime/GaoGaiGar''
* J from ''Anime/HeatGuyJ''
* J from ''Manga/BoboboboBobobo.'' You know, the one with the garlic/onion (the heroes can never decide this) for a head?
* In the Diamond/Pearl saga of the ''Anime/{{Pokemon}}'' anime, a villain known as Pokemon Hunter J and a one-shot filler character known as O were introduced. %% N from Black/White goes in the game section. %%
* In ''{{Manga/Pokemon Adventures}}'', the protagonists of each arc are named after their generation's games. So the protagonists for the XY arc are named... X and Y. Granted, when romanized their names become Ekkusu and Wai, [[AerithAndBob but it still doesn't make their names any less weird.]] Averted with Y in the Viz version, as her actual name is [[DubNameChange Yvonne]] but has 'Y' as her nickname.
* ''Manga/{{Gravitation}}'''s K. (Although his actual name is revealed later.)
* K in ''Anime/PuniPuniPoemi''.
* L from ''Manga/DeathNote''. A handful of other characters use one-letter codenames at some point, as well, (most notably [[spoiler:L's successor Near]] first introduces himself as N) but, as [[AllThereInTheManual revealed in the "how to read" book]], [[spoiler:L actually is his first name. The full name being L Lawliet.]]
* L-sama from ''LightNovel/{{Slayers}}'' novel afterwords. Though this is an abbreviation of L.O.N. or Lord of Nightmares.
* IdolSinger [[ThemeTwinNaming twins]] L and R Nomura in ''Anime/MarginalNumber4''
* In ''Anime/ValvraveTheLiberator'', soldiers trained at the Karlstein Institute have their real names taken, and they are replaced by combining this with YouAreNumberSix. So we have L-Elf (Elf meaning 11), and several others.
* X from Manga/MajinTanteiNougamiNeuro.
* Y in ''LightNovel/HumanityHasDeclined''. Assuming that's her actual name, seeing as [[NamelessNarrative no one else has one...]]
* The main antagonist of the third ''Anime/TenchiMuyo'' OVA goes by Z, remarking that his real name, Z-0001332536893, is too long.
* ''Anime/{{Mazinger}}'' universe: {{Fanon}} often refers to the eponymous HumongousMecha Mazinger Z as simply "Z".
* Z, the BigBad from the [[AntagonistTitle eponymous]] ''OnePiece'' movie ''Anime/OnePieceFilmZ''.
* The Alphabets, Major Eberbach's subordinates in ''Manga/FromEroicaWithLove'', are each known by one single letter as a codename. The Major always seems to have 28 of them around despite having sent some to Alaska. (Also, the letters are pronounced like German alphabets.)
* In ''Manga/{{Naruto}}'', a lot of people from the Village Hidden in the Clouds: The Raikage is "A", his brother is "B" (though [[OnlyKnownByTheirNickname everyone called him "Killer Bee"]]), he has an aide named "C" and they sent a shinobi after Sasuke, who was called "J", and an incidental character was named "F". In this case, these are code-names/ranks (that may have fully replaced the characters' original names which are never revealed). For example, B is given the name after being chosen as the combat partner for A when he was promoted to head of the village and its armed forces (implying the Raikage is always called "A" and paired with an assistant/bodyguard called "B").
* The [[Anime/MobileSuitGundamWing Gundam Engineers]] Doctor J, Professor G, Doktor S, Instructor H, and Master O. The sequel novel ''Frozen Teardrop'' has Trowa and Quatre taking similar aliases Doktor T and Instructor W, as well as revealing Doctor J's real name: [[spoiler:Jay Nul]]
* ''Anime/CControl'' (itself a OneLetterTitle) has an [[{{Mons}} Asset]] going by the name Q. Also, [[spoiler:a chain reaction that impacts the global economy when a Financial District goes bankrupt]] is simply known as [[TitleDrop C]].
* ''Manga/BungouStrayDogs'' has a character that ''technically'' has a full name, but is only ever referred to as Q by the other characters.

[[folder:Audio Plays]]
* Ixpellia from ''Audioplay/StrikerSSoundStageX'', whose nickname of Ix/Ikusu is transcribed in English as "X" in the CD booklet.

[[folder:Card Games]]
* [[http://ww2.wizards.com/gatherer/CardDetails.aspx?&id=74252 This]] ''TabletopGame/MagicTheGathering'' card (from an official joke set) has a ''zero'' letter name.

[[folder:Comic Books]]
* Trenchcoat Brigade member MisterE from ''ComicBook/TheBooksOfMagic''.
* V from ''ComicBook/VForVendetta''.
* ''ComicBook/XMen'':
** Professor X. It's short for Xavier.
** Then there's X-Man.
** M (Monet St. Croix) from ''ComicBook/GenerationX'' and ''Comicbook/XFactor''.
* WesternAnimation/ActionMan's nemesis [[MorallyAmbiguousDoctorate Dr. X]]
* The anti-hero protagonist of ''ComicBook/{{X}}''.

[[folder:Films -- Animation]]
* Woody Allen's character Z in ''WesternAnimation/{{Antz}}'' (short for Z-4195).
* Professor Z, TheDragon of ''WesternAnimation/Cars2''.

[[folder:Films -- Live-Action]]
* F, the voiceless vampire girl in ''Film/{{Marebito}}''.
* G, of the movie ''Holy Man'' (played by Creator/EddieMurphy) -- the titular character, in this case.
* In ''Envy'', Creator/ChristopherWalken's hobo character calls himself "the J-Man."
* The film ''Film/TheLeagueOfExtraordinaryGentlemen'' has M, who is the one who gathers the League and gives them their task. Of course, it turns out that M stands for [[spoiler:[[Literature/SherlockHolmes Moriarty]]]].
* ''Film/VForVendetta'': "Voilà! In view, a humble vaudevillian veteran, cast vicariously as both victim and villain by the vicissitudes of fate. This visage, no mere veneer of vanity, is a vestige of the vox populi, now vacant, vanished. However, this valorous visitation of a bygone vexation stands vivified, and has vowed to vanquish these venal and virulent vermin vanguarding vice and vouchsafing the violently vicious and voracious violation of volition! The only verdict is vengeance; a vendetta held as a votive, not in vain, for the value and veracity of such shall one day vindicate the vigilant and the virtuous. Verily, this vichyssoise of verbiage veers most verbose, so let me simply add that it's my very good honour to meet you and you may call me V."
* Willem Dafoe's character in ''New Rose Hotel'' is known only as X.
* X, leader of the alien invaders in ''Film/GodzillaFinalWars''. He says it's just a nickname for the humans to call him because his real name is [[TheUnpronounceable too hard for humans to say]].
* X is one of the men going to the Million Man March in ''Get on the Bus''. Flip doesn't believe it's his real name, and it isn't -- it's short for Xavier, but he's always preferred "X".
* Z (pronounced Zed) from (and short for) ''Film/{{Zardoz}}''.
* ''Film/MenInBlack'' agents, including Agents J, K, L, and Zed[[note]](i.e., "Z" in any English-speaking country except the U.S., and French-speaking countries as well)[[/note]], along with almost everyone else with the organization. The third movie adds an "AA", but it's only in a BadFuture anyway. Interestingly, the names appear to be based on the first letter of the first name (James, Kevin, Laura, [[Music/MichaelJackson Michael]]). This begs the question -- are there only 26 agents in the MIB? What happens when two agents have their first names start on the same letter?
* The ''Film/JamesBond'' films famously have several of these.
** Bond's boss M, based on the RealLife head of Mi6, who goes by the codename "C". It's mentioned in ''Film/CasinoRoyale2006'' that M is not just a random letter (whether it references a name -- the novels have the original [[AlliterativeName Miles Messervy]] and Barbara Mawdsley, a prop in ''Film/{{Skyfall}}'' has the name [[http://www.dailymail.co.uk/news/article-2319598/Mystery-surrounding-James-Bond-mentor-Ms-real-revealed-007-fan-discovers-character-played-Judi-Dench-called-Olivia-Mansfield.html Olivia Mansfield]] - is unclear):
--->'''Bond:''' I had no idea it stood for--\\
'''M:''' Utter one more syllable and I'll have you killed.
** Gadgeteer Q ("Q" being short for "Quartermaster"/"Quartermaster's department", referencing his job to supply agents).
** Q's assistant, dubbed as R ("reserve"), before he gets promoted to Q.
* ''Film/FaustLoveOfTheDamned'': The main bad guy is known only as "M", though it's presumably short for [[LouisCyphre Mephistopheles]].

[[folder:Fan Works]]
* The ''WesternAnimation/MyLittlePonyFriendshipIsMagic'' fanfic ''Fanfic/{{Jericho}}'' has C, a villain.
* The BigBad of ''Fanfic/{{Pokeumans}}'', Mr. X.

* ''Via Reader's Digest, 1958'':
-->My friend R.B. Jones doesn't have a first or middle name only the initials R.B. This unusual arrangement was never a problem until he went to work for a government agency. The government is not accustomed to initialed employees, so R.B. had a lot of explaining to do. On the official forms for the payroll and personnel departments, his name was carefully entered as R (Only) B (Only) Jones.\\\
Sure enough, when R.B. got his pay check, it was made out to Ronly Bonly Jones.\\

* In ''Literature/TheBourneSeries'', Jason Bourne went by the military-alphabet name Delta when he was in the Medusa program in Vietnam.
* General G in the novel ''Literature/FromRussiaWithLove''. Probably at least partly because of his [[OverlyLongName long freakin' name]], Grubozaboyschikov.
* OlderThanTelevision: The protagonist of ''The Castle' by Creator/FranzKafka is known only as K.
* The protagonist of Franz Kafka's ''The Trial'' is named Joseph K.
* In ''Literature/SputnikSweetheart'', the narrator is only ever known by the letter K.
* In the Japanese novel ''{{Kokoro}},'' [[TheMentor Sensei]] writes a long testament about his relationship with his dead friend, whom he only refers to as "[[ThePhilosopher K]]."
* As the title probably suggests, the heroine of the erotic classic ''The Story of O'' is known only by her initial.
* S (aka "The Stooge"), the protagonist of Paul Pope's sci-fi graphic novel, ''HeavyLiquid''.
* V from ''Vegan Virgin Valentine''. Her full name is [[AddedAlliterativeAppeal Vivienne Vail Valentine]], so you can see why she shortens it.
* ''Literature/ToKillAMockingbird'' has a bit character called X Billups. Most people didn't believe that was his full name until he was asked to spell it during a court case.
* John Hackworth's nemesis Dr. X in ''Literature/TheDiamondAge''. (A slight subversion in that his actual name is quite long, but it is very hard to pronounce, so everyone just calls him Dr. X. Interestingly, his ''Chinese'' name is written with only one character as well.)
* 6 and @ from Max Berry's book ''Syrup''. [[spoiler:When 6 was born, her parents named her 0 (zero), then on her first birthday, she was renamed 1, up until they were killed when she was, yup, six years old. The name stuck. As for @, well, it's not explained, but 6 says she only did it to copy her.]]
* In ''[[Literature/TwentyOneBalloons The Twenty-One Balloons]]'' by William Pène du Bois, the island of Krakatoa is settled by twenty families, who take on the letters A through T as names (e.g., the man who founded the island is only known as Mr. M, his wife is Mrs. M, and their children are M-1 and M-2). When the protagonist is stranded there, he asks if they would like to start referring to him as Mr. U; they decline, as it would lead to pronoun confusion. No mention is made of how they manage to non-confusingly talk about the I family, though at least I is only a pronoun in the subjective case.
* Members of the Audubon Ballroom in ''Literature/HonorHarrington'' use X as a surname, though most have a different legal name.
** As an extension of this, freed slave and noted academic Web Du Havel's full name is W. E. B. Du Havel. He didn't understand how names work when he needed to provide one for the record, so W. E. B. doesn't actually stand for anything.
* The Aann, a reptilian race from the ''Literature/HumanxCommonwealth'' novels, use a string of capital letters in place of a surname. As they advance in rank within their society, letters are removed from these strings, meaning that the Emperor of their kind has a one-letter surname.
* E.E. "Doc" Smith and Stephen Goldin's ''Family D'Alembert'' series has two major villains: Lady A, and someone (or something) called C. However, there is no B in the hierarchy (nor D through Z for that matter) and C is actually the boss. Why this is so is only revealed when it's almost too late to save the situation.
* J. Eugene Raxford in Donald E. Westlake's ''The Spy in the Ointment'', due to not being given real names by the FBI agents he's forced to deal with, mentally refers to them as Agent A, B, etc.
* The protagonist of ''I Am J'' is a teenage trans boy whose name is "J". Early in the book, a flashback shows that in sixth grade he gets into a confrontation with a teacher when she kept on calling him "Jenifer", though his soon-to-be friend Melissa stepped in and made an excuse that he couldn't be called "Jenifer" because of an incident in his family that caused the name to bring up negative memories.
* In Ödön von Horvaths novel ''Jugend ohne Gott'' the narrator only refers to his students by letters, which are implied to be the first letter of their first names.
* The protagonist of the teen novel ''M in the Middle'' is an autistic teenager whose obsession with the letter M has led to her adopting it as her name and refusing to answer to her real name.
* In ''Literature/GravityFallsJournal3,'' the Author only refers to his friend/lab assistant as "F." Of course, those who have watched [[WesternAnimation/GravityFalls the show]] already know that it's short for F[[spoiler:iddleford [=McGucket=]]].

[[folder:Live-Action TV]]
* A, the main antagonist of ''Series/PrettyLittleLiars''.
* Mister F from ''Series/ArrestedDevelopment''. It turns out to be a subversion. [[spoiler: MRF actually stands for Mentally Retarded Female.]]
* G Callen from ''Series/NCISLosAngeles'' (his first name accidentally vanished when he was put into foster care). When they finally track it down, the building explodes before Callen can open the drawer. In season seven, his full name is eventually revealed to be G[[spoiler:risha Aleksandrovich Nikolaev]] Callen.
* Horatio Caine, usually just H, from ''Series/CSIMiami''.
* Played for laughs in ''[[Series/HermansHead Herman's Head]]''. Jay goes to a Sex Addicts Anonymous meeting and to maintain his confidentiality declares he will introduce himself by the first letter of his name.
* Mr. K from ''Series/GoOn''. It may or may not be short for something, but given [[{{Cloudcuckoolander}} his odd mental state]], it's probably not worth asking.
* Q from ''Franchise/StarTrek''. Since it's used for both the character and the species to which he belongs, things can get confusing when other Qs show up. (Though it's less so in print: the second Q from "Deja Q" is rendered as Q2, and Q's son is q.) An ExpandedUniverse trilogy adds another god-like being named 0. That's right, a One ''Digit'' Name. There's also <*> (that energy cloud from TOS causing humans and Klingons to fight), a One Asterisk Name.
* Mr. X, Mulder's second MysteriousInformant from ''Series/TheXFiles''.
* Lord Zedd from ''Franchise/PowerRangers''. His {{Mooks}} had this letter on their breastplates.
** ''Series/PowerRangersSPD'' had a character named Z, short for Elizabeth.
** ''Series/PowerRangersRPM'' has a character known only as Dr. K, later explained as being because she grew up in a secret government think-tank codenamed "Alphabet Soup". Presumably Dr. A through Dr. J had non-Ranger based areas of expertise.
* One episode of ''Series/{{Shark}}'' involved a fashion designer named Z Pruitt. He was much ridiculed.
* ''Series/DoctorWho'' has a villain named Omega.
** In "The Happiness Patrol", the natives of Terra Alpha all have one-letter surnames denoting social rank. Offworlders have their surname replaced by 'Sigma'.
** The Doctor himself has been known to sign his name as simply "?".
* ''Series/GetSmart'': When Max and the Chief swap roles due to a bureaucratic foulup, the Chief goes back to his old designation of Agent Q (he joined CONTROL before they switched to numbers).
* On ''Series/{{Dollhouse}}'', all the actives in the LA house are apparently assigned a letter, but are referred to as the military phonetic code for said letter (Alpha, Echo, November, Sierra, Whiskey, etc). How they deal with having more than 26 actives is never addressed; quite possibly they just don't ever have that many.

* The alternative rock band A, though they were originally called Grand Designs.
* E from the band Music/{{Eels}}, who used to also make solo albums under that name, until he decided it made his music too hard to track down. He has gone by his real name though - his autobiography ''Things The Grandchildren Should Know'' and [[PopStarComposer the soundtrack to the film]] ''Levity'' are both credited to Mark Oliver Everett. He initially started being called E in high school because he just [[OneSteveLimit knew too many other people named Mark]].
* Ian "H" Watkins of Steps.."
* L from Music/{{Infinite}}.
* M, the new-wave band most famous for "Pop Muzik".
* N from Music/{{VIXX}}.
* V from Music/{{BTS}}.
* Music/HelloProject former group W. Quite tricky to search for their material, if it wasn't for one of their alternate names, Double You.
* If plurals of a single letter count, short-lived Christian swing/ska band The W's.
* X was at the forefront of the Los Angeles punk scene.
* Music/XJapan was known in its early years only as X; they adopted the "Japan" once they broke into the international market, to distinguish from the above.
* Y is Music/{{AOA}} drummer Youkyung's "angel name"[[note]]To go with the group's angel concept they were given stage-names called "angel names" at debut.[[/note]] but like the other members' angel names it's stopped being used for the most part.
* Y is also the stage name of Choi Sungyoon, a member of Music/{{Infinite}}'s "brother group"[[note]]signed under the same company, Woollim Entertainment[[/note]] [[https://en.wikipedia.org/wiki/Golden_Child_(band) Golden Child]], who debuted in August of 2017.
* In Vivian Stanshall's comedy LP ''Sir Henry at Ndidi's Kraal'', the eponymous Sir Henry Rawlinson mounts an expedition to [[DarkestAfrica Africa, the "dark incontinent"]]. He can't remember his native bearers' names, so "to their - ahem - cheery delight, I ''numbered'' the sods. The last twenty-seven I named after the letters of our alphabet. The twenty-seventh - knew you were going to ask me that! - was a question mark.

[[folder:Pro Wrestling]]
* After Kodo Fuyuki stripped Hayabusa of his [[TheGimmick gimmick]] and gave it to Mr. Gannosuke in [[Wrestling/{{FMW}} Frontier Martial-Arts Wrestling]], the former Hayabusa became the [[JapaneseDelinquents delinquent]] known as H.[[/folder]]

[[folder:Tabletop Games]]
* In TabletopGame/{{Pathfinder}}, there's a Monk archetype which - at high levels - allows the monk to heal and resurrect all their allies in return for being wiped from existence to the extent that their name can't be written down. It has been proposed that one could abuse the one letter name trope to use 26 monks to destroy the alphabet.[[/folder]]

[[folder:Video Games]]
* A from ''[[Franchise/{{Digimon}} Digimon: Digital Card Battle]]''. [[spoiler:It's a pseudonym]].
* D in ''''VideoGame/AnotherCode: Two Memories'' (a.k.a. ''Trace Memory''). [[spoiler:D turns out to have been a nickname. His real name is Daniel.]]
* D is the default name of the main character in ''VideoGame/CrystalStory II''.
* The second character David meets during the events of ''Videogame/TheCrookedMan'' calls himself D. He refuses to give out his full name.
* D from ''VideoGame/GrandTheftAutoV''.
** Also, Michael, Franklin and Trevor often call oneanother M, F and T.
** Just like the protagonists, Bratt is also called B in the opening mission.
* At one point during ''VideoGame/VampireTheMasqueradeBloodlines'', you run into a thin-blood named E, who asks you to find out about thin-bloods and rescue his girlfriend and sire, Lily. The Malkavian run lampshades this at one point, referring to him in conversation with Lily as "the letter that comes before F and G".
* G from ''VideoGame/HouseOfTheDead'', who, despite being the only one with such a unique name, is pretty ordinary for a secret agent. It becomes a RunningGag in ''VideoGame/TheHouseOfTheDeadOverkill'', where G constantly refuses to answer what the letter means whenever people ask him.
* G from ''[[VideoGame/BubbleBobble Bust-A-Move 4]]''. He's an old wizard, but he acts like a senile old coot to throw people off.
* H, an otherwise unremarkable {{mook}} from the video game ''Fighting Force''. Also features an Agent X toward the end.
* Double H from ''VideoGame/BeyondGoodAndEvil'', [[spoiler: though this is just a codename, his real name is Hubb]]
* J from ''VideoGame/FinalFight''.
* Julius Belmont from ''Castlevania: Aria of Sorrow'' refers to himself as J until he regains his memory.
* The main playable character of ''VideoGame/EliteBeatAgents'' is known as Agent J.
* ''VisualNovel/ZeroEscape'':
** Late in ''VisualNovel/NineHoursNinePersonsNineDoors'' [[spoiler: the narrator]] introduces herself as "I am I, the ninth letter of the alphabet".
** K from VisualNovel/VirtuesLastReward. Technically Phi and Sigma too, although their names are spelled out in English. [[spoiler:[[MeaningfulName K is a placeholder variable in math]], hinting at his switch with Akane in the true timeline and Sigma's name references his ability to remember memories from multiple timelines.]]
** Q from ''VisualNovel/ZeroTimeDilemma''. Also [[spoiler: Delta in the same fashion as Sigma and Phi above]].
* K′ from ''VideoGame/TheKingOfFighters'' (the apostrophe-like symbol, pronounced "dash" or "prime", is the mathematical notation for derivatives, [[MeaningfulName a hint of his origin as a genetically altered clone of Kyo Kusanagi]]).
* [[PaperThinDisguise Mr. L]] from ''VideoGame/SuperPaperMario'', though that's not his real name. [[spoiler: He's Luigi, much to the surprise of no one.]]
* Inverted in the PC game ''N'': [[IAmNotShazam most people think the main character ninja's name is N]], but actually the ninja is nameless and N represents "the way of the ninja", a system of beliefs to which the ninja subscribes. These details are found on N's "Story" page.
* N from ''VideoGame/PokemonBlackAndWhite''. (The Japanese games actually use the English letter as his name, a rarity in a JRPG). It's short for [[spoiler:Natural, as in natural number]], so it makes sense.
* O is the name of a minor NPC in ''VideoGame/PlanescapeTorment''. He's not just any old O, but part of the "divine alphabet." Whatever that means, he can give you a permanent boost to your Wisdom if you ask the right questions, before vanishing.
* Dr. O from the "Old World Blues" DLC for ''VideoGame/FalloutNewVegas''. [[spoiler: Only not really - while everyone ''calls'' him O, his actual name is [[YouAreNumberSix 0]].]]
* Q from ''VideoGame/StreetFighterIII 3rd Strike''. The third season of ''VideoGame/StreetFighterV'' is introducing a newcomer named G, as well.
* Mr. X, the BigBad of ''VideoGame/MegaMan6''. [[spoiler: He turns out to be Dr. Wily, to the surprise of no one.]]
* Z, late-game mooks with WolverineClaws in ''VideoGame/CaptainCommando''.
* 3 from ''VideoGame/ThreeInThree'' (though she's an anthropomorphisation of the actual ASCII character "3", so this is as much a job description as it is a name).
* Mr. X and Robot Y from the ''VideoGame/StreetsOfRage'' games.
* Many of the main characters from the ''VideoGame/MegaManX'' series:
** The main character, X. Technically a shortening of Megaman X, [[AllThereInTheManual but no one ever calls him that in series.]]
** Technically, Zero is a one-number name (0).
** Sigma (∑) is also one letter name, but with a Greek letter. His name is actually written with the Greek letter, and is the symbol on the health bars of anyone associated with his organization in later games.
** And [[VideoGame/MegaManZero Omega]] (Ω.)
** R from ''VideoGame/MegaManXCommandMission''.
** And Epsilon (E), the game's villain.
** The Biometals in ''VideoGame/MegaManZX'' are all named "Model [Single Letter]."
*** The letters are derived from the names of the guardian the biometal is based on. So Model P for the ninja [[VideoGame/MegaManZero Phantom]] and Model X for... well... X.
* ''VideoGame/ResidentEvil2'':
** The mutant form of William Birkin is officially called "G", but most players simply refer to him by his real name.
** The Tyrant from the same game was also given the nickname of "Mr. X" in the American version.
* ?, the character of ''neu'' from ''VideoGame/PopnMusic''. There is also a ∑ in a different song.
* The main character from ''VideoGame/FreezeME'' is just called R, and her best friend is a dog named M. No real reason for it is given InUniverse--probably they just sound cool.
* One of the playable characters of ''VideoGame/XenobladeChroniclesX'' is named L. Technically, his full name is L'cirufe, but he prefers to go by just the first part.
* The villain in ''Ominous Objects 4: Lumina Camera'' is known only as Z.
* ''VideoGame/CrisisCore'' has a series of sidequests revolving around telepathic messages from {{esper}} called P.
* The mysterious QuestGiver issuing orders to defeat the Four Archangels in the ''VideoGame/ShinMegamiTenseiIV'' is called M. [[spoiler: To everyone's surprise, it's [[NiceGuy Mastema]], who in ''VideoGame/ShinMegamiTenseiStrangeJourney'' had been an irredeemable jackass.]]

[[folder:Web Comics]]
* Elzandra Ayla [[spoiler: Umbria]], AKA Alexandra Underwood of ''Webcomic/AMagicalRoommate'', prefers to be addressed as X. Nobody's sure why. Maybe it has to do with the fact that [[TheQuietOne she rarely says a word with more than three syllables in it, and Alexandra has four.]]
* ''Webcomic/GirlGenius'' has a minor character named [[OverlyLongName Zami Yahya Ahmad ibn Suliman al-Sinhaji]], who asks to be called "Z".
* The ''Webcomic/IrregularWebcomic'' "Espionage" theme (a spoof of ''Film/JamesBond'') has characters named Ñ and Ü. Apparently turnover was so high that they ran out of ordinary letters.
* The vampire that killed Blaine's parents and has been stalking and murdering his family for generations in ''Webcomic/CharbyTheVampirate'' is only known as "N".
* ''Webcomic/GrrlPower'' has the Arcdark agent X. According to him, it's supposed to be forgettably generic.
* Attley's pet spider Mrs. F in ''Webcomic/TheSanityCircus''.
* In ''Webcomic/BoyfriendOfTheDead'' due to GhostAmnesia N has no idea what his name was while alive. He does have a business card with his face on it, but a combination of being ripped up then taped back together and covered in bloodstain's has rendered it illegible, save for the first letter of his name: "N". [[OnlyKnownByTheirNickname So that's what they call him]].

[[folder:Web Original]]
* Coach Z, from ''WebAnimation/HomestarRunner''. Didn't start out this way, as his name was spelled "Coach Zee" in the original book of ''Where My Hat Is At?'', presumably to prevent his name from being pronounced "Coach ''Zed''".
** In answering an email from Canada, Strong Bad reasons that Coach Z would be called "Coach Zed" there and decides to call him that in the future ([[NegativeContinuity Although he doesn't]]).
* Happens frequently in LetsPlay/TwitchPlaysPokemon, [[RunningGag especially with the letter A]].
** One notable character specific to TPP with a different letter is "d", the protagonist of ''LetsPlay/TwitchPlaysPokemonX'', also known as "Li'l d".
* ''Literature/WhateleyUniverse'': Mr. X, of the Brooklyn Sentinels, as said in [[http://whateleyacademy.net/index.php/stories/357-saks-and-violence Saks and Violence]]:
--> The guy working the "Question" look with the blank face mask and the leather trench coat is Mr. X. And Mr. X may have some sort of invulnerability angle, but give him his due, he does a good job of working the "crazy prepared" and "badass trench coat" tropes.

[[folder:Western Animation]]
* The ''WesternAnimation/MenInBlack'' animated series also has Alpha, one of the founding members of MIB and K's mentor, before he went rogue. When he first meets J, he introduces himself as agent A. When J later mentions A to K and Zed, Zed points out that there is no agent A.
* [[TheVoiceless B]] from ''[[WesternAnimation/TotalDrama Total Drama Revenge of the Island]]''. It turns out it's short for [[spoiler:[[GenderBlenderName Beverly]]]].
* Substitute teacher Mr. E in ''WesternAnimation/{{Recess}}''. Helps his badass mystique that gets him to cow the rest of the class into doing what he wants (in a good way!)... Except for the resident idealist T.J. (Theodore Jasper, in case you were wondering. He's not an example of this trope, he just uses it as a better-sounding nickname. Can you blame him?) They find common ground in the end anyway.
-->'''T.J.:''' So, can I ask what the E stands for?\\
'''Mr. E:''' No.\\
'''T.J.:''' You are ''so'' cool.
* In one episode of ''WesternAnimation/TheSimpsons'', Homer decides to find out what his middle initial J stands for. It turns out, it stands for Jay.
* ''WesternAnimation/InvaderZim'' plays with this, and has a character named "The Letter M".
* ''N'' the Eliatrope from ''WesternAnimation/{{Wakfu}}: Les Gardiens'' and ''VideoGame/{{Dofus}}''.
* O is also one of the racers in the Oban cycle of ''WesternAnimation/ObanStarRacers''
* "X Agent" from ''WesternAnimation/SheepInTheBigCity''. The trope was parodied in his first appearance:
-->'''General Specific:''' I don't want an "X Agent"! I want a ''current'' agent!\\
'''Private Public:''' The "X" is put in to indicate mysteriousness rather than his job status sir.\\
'''General Specific:''' Well why can't he choose another letter? Like "K"?\\
'''Private Public:''' "K" isn't as mysterious a letter as "X", sir.\\
'''General Specific:''' What about "L"? "L" is pretty mysterious! ''[waving fingers]'' Llllllllllllll... Lllllllll!!!\\
'''Narrator:''' So as General Specific re-acquaints himself with the alphabet...
* X, later know as Rampage, from ''WesternAnimation/BeastWars''.
* X Racer, (named after his uncle's codename), from ''WesternAnimation/SpeedRacerTheNextGeneration''.
* Z from ''WesternAnimation/AllGrownUp''. [[OverprotectiveDad Chas]] tries asking what it's short for, but he says "It's just Z."
* ''WesternAnimation/TheZetaProject'' has Infiltration Unit Zeta. His companion Ro calls him Zee, and sometimes he uses "Zee Smith" as an alias while pretending to be human.

[[folder:Real Life]]
* The head of Britain's Secret Intelligence Service (a.k.a. MI6) is always codenamed "C", in honor of the original head, Mansfield Smith-Cumming. In the same vein, the head of ''MI5'' is called K, after Vernon Kell. If any British intelligence officers are codenamed "M", that apparently has yet to be declassified.
** As Creator/AlFranken points out while talking about the Downing Street Memos in ''The Truth (with jokes)'', there are a number of other individuals in British government given single letter codenames. He mentions a meeting involving "C, Z, R, and a group called 'the vowels'."
* In botanical publications, Carl von Linné (aka Carolus Linnaeus, the father of modern botanical nomenclature) usually gets his name abbreviated to just "L."
* [[TheTropeFormerlyKnownAsX The artist formerly known as "The Artist Formerly Known as]] Music/{{Prince}}" had, during the time when he was known by the quoted name, an unpronounceable symbol as his name. Said symbol, while not a alphabetical letter, still had to be printed during this time, and Warner Brothers had to send out floppy disks of a special font that included the symbol so that print media could print it.
* There are several one-letter geographic names, including:
** D, "the world's shortest" river in Oregon.
** E, a township in Maine.
** Å, Nordic for "brook", a dozen places in Scandinavia. There are also 249 Norwegians with this as a surname, spelled "Aa". It's pronounced "awe", by the way.
** Y, a commune in northern France; amusingly, "y" is [[PunnyName French for "there."]]. Also a "census-designated place" of the same name in Alaska. And a short river in Siberia.
** Mount E, a volcano in Northern Japan.
** Ö, Nordic for "island", several places in Scandinavia. Linguistically the same as "öja" or "eya", and survives in many English place names as suffix ''-ey'', such as Jersey, Guernsey and Alderney.
* A writer for ''Wired'' magazine named his daughter "E" with the intent of letting her choose her own name later on. She decided to stay as "E".
** He then did a complete 180 and gave his son a [[OverlyLongName name that wouldn't fit in a single row of text on this page]].
* ? of the band ? and the Mysterions, although ?'s name[[note]]It's widely believed that his birth name was Rudy Martinez, but his legal name was "?."[[/note]] is normally rendered as "Question Mark" in interviews.
* UsefulNotes/HarryTruman's name is in full "Harry S. Truman". Besides having the name "Harry"--usually a nickname for Henry or Harold--as his actual first name,[[note]]He was named after his maternal uncle Harrison "Harry" Young, but that doesn't change the fact that his name was Harry, not Harrison[[/note]] the "S" famously doesn't stand for anything. His middle name was really just "S.". This was apparently an old Scots-Irish tradition, revived by Truman's family because they couldn't decide if they wanted his middle name was to be "Solomon" (after his maternal grandfather Solomon Young) or "Shipp" (after his paternal grandfather Anderson Shipp Truman). However, the UrbanLegend that his name was "S" without a period is false--he almost always spelled his middle name with a period, despite it not standing for anything--the legend comes from a joke that the famously folksy Truman once told the press.
** Ulysses S. Grant is in the boat as well, though his name came about due to a clerical error when he enrolled at West Point: his birth name was Hiram Ulysses Grant, which rather unfortunately abbreviated to "H.U.G."--not exactly the kind of nickname you want either on the frontier (he grew up in the then-relatively backwoods area east of Cincinnati) or at a military academy, which is why he wasn't in any hurry to correct the Academy administration when it messed up his name. Later, Grant did take on the nickname "Sam".
* H Ty Warner, the founder of Ty Inc. (creators of Toys/BeanieBabies and various other plush toys). He added the "H" as an affectation.
* Music/JohnnyCash's birth name was J. R. Cash because his parents could not think of a good name at the time. He later changed it to John R. Cash (the middle initial still didn't stand for anything).
* An unusual variant (even for this list) is journalist Jennifer 8. Lee. Yes, her middle name is the number 8. Apparently, she chose it as a teenager as she wasn't given a middle name at birth. On legal documents, it's spelled out "eight" when numbers aren't allowed.
* Actress S. Epatha Merkerson (best known as Anita Van Buren in ''Series/LawAndOrder'') legally changed her first name from "Sharon" to "S".

!!Examples of One-Letter Surnames:
* Vanilla H from ''VideoGame/GalaxyAngel''.
* In RealLife, O is a genuine Belgian surname. It also shows up in Hispanic countries, with some people called "de la O".
* Mr. T pities the fools who haven't added him to this list. He legally changed his name from Lawrence Tureaud so people would have to call him Mister.
* Louis V. from ''Manga/LoveIsInTheBag''. [[spoiler:Subverted, it's "Vee".]]
* UsefulNotes/MalcolmX
* Y ([[SpellMyNameWithAnS or I, or Yi]]) is the second most common family name in Korea, shared by about 20% of the population. Pronounced "ee". In much of the West, however, they take up the more traditional "Lee" (or "Rhee", or... okay, forget it) just to make things less confusing (it matches up better with the Chinese pronunciations for the same character, and it is not incorrect: the traditional spelling is in fact "Ri", a pronunciation still retained in much of the north).
** So, in a moment of great drama, if you wanted to have an epic SayMyName moment with a person by this surname, you could [[ShoutOut literally shout out]] "''[[Manga/JoJosBizarreAdventure Riiiiiiiiiiiiii!]]''"
** The Korean surname Lee/I would use two letters, but one character. The majority of Korean surnames are one character, but made up of 2-3 letters. It is impossible for any words to be one letter in Korean.
** Except Lee/I uses the null symbol which isn't a letter. It is just a place holder for no sound. At least 2 symbols but one sound which would correspond to a letter is possible.
* A valid Korean name is A O. A double dose of One Letter Name!