Theme Twin Naming

"Kevin E. Levin: Ken? Your brother's name is Ken? Ken and Gwen Tennyson? What are your folks' name, Sven and Jen? I'm talking to you, Ben."

- Ben 10: Alien Force

"Carly: If you did have a twin brother, why would his name need to sound similar to yours?"

- iCarly

When twins appear in fiction, it's very likely that their names will somehow sound similar, be it through rhyme (Tyler and Skyler), alliteration (Michael and Michelle), anagrams (Amy and May), or some other kind of theme. Commonly there is only a one letter difference between the names.

If the twins are often referred to as one individual (e.g. "Jim" and "Tim" are almost always called "Jim-and-Tim" in conversation) this is even more likely, so it's understandably very common with Single-Minded Twins.

Also, a character's Evil Twin will often have the same name as the character, only reversed, e.g. the evil twin of Alfred will be named Derfla. Of course, if the character's name is something like Bob, this leads to some confusion.

In Japanese and other syllable-based languages this is especially common, because twins often end up sharing either the first or the final characters of their names. Most definitely Truth in Television.

Like most twin tropes, this annoys the hell out of many real-life twins. Child psychologists even advise parents against the practice, since it can impede the children's development as individuals.

A subtrope of Family Theme Naming.

Anime and Manga

 * Kyon of Suzumiya Haruhi calls Mikuru's fake twin "Michiru", playing off this trope.
 * From the anime W Wish, there's twin siblings Junna and Senna.
 * Appears in several CLAMP works:
 * Sisters Tarta and Tatra from Magic Knight Rayearth.
 * Fraternal Half-Identical Twins Hokuto and Subaru of Tokyo Babylon and X 1999 are both named after constellations of seven stars. Subaru (昴) is Pleiades, while Hokuto (北都) means The Big Dipper. The seven stars theme is quite significant in X.
 * Cho Li and To Li from Miyuki-chan in Wonderland (themselves analogs to Tweedledee and Tweedledum).
 * In Chobits, Freya and Elda/Urda are named after Norse Goddesses.
 * CLAMP appears to have restrained themselves with the twins of Tsubasa Reservoir Chronicle, however, since their names have no apparent meaning and may have been intended to simply sound foreign to Japanese readers.
 * Maru and Moro of ×××HOLiC, whose full names are Marudashi and Morodashi (meaning "flashing" and "streaking", Yuuko has an odd sense of humor).
 * Suiseiseki and Souseiseki of Rozen Maiden ("Jade" and "Lapis Lazuli" respectively, also matching up to their dress colors).
 * Mion and Shion from Higurashi no Naku Koro ni. The "on" in both names is the same kanji, 音 (meaning "sound").
 * Sakon and Ukon of Naruto take this a bit further than most—they actually share the same body, and the first kanji in their names mean "left" and "right" respectively. Also, Hinata and Neji's fathers are twins: Hiashi and Hizashi, which mean "daytime" and "sunlight" respectively, and both contain the kanji for "sun" like most Hyuga family members.
 * Ranma ½ had Chinese Girl twins Pin-Ke and Lin-Ke (Pink and Link in some translations) and (anime-only) separate characters Rinrin and Ranran (Ling-Ling and Lung-Lung in the translation).
 * Mermaid Melody Pichi Pichi Pitch had There's also the Black Beauty Sisters, Mimi and Sheshe, although "sisters" is just a stage name (possibly so they could get away with public displays of affection in the seven-AM programming block). Although being a pair of enchanted anglerfish, they probably are sisters. The other pair of twins in the series, Caren and Noel, do not match.
 * Digimon Tamers has Ai and Makoto, meaning "Love and Truth" respectively, as well as being the title of a popular book.
 * Likewise, Digimon Frontier had Kouichi and Kouji - "First Radiance" and "Second Radiance".
 * Tiff and Tuff in Kirby Right Back At Ya. This does not match in the original, as their names were Fumu and Bun, respectively.
 * The Meido twins from Tsukihime, Hisui (jade) and Kohaku (amber), are named after their respective eye colors.
 * Momiji and Kaede of Blue Seed are both named after words for "Maple".
 * In Harukanaru Toki no Naka de, the story about Nue has him followed around by two deers whom he calls Momiji and Kaede. Whether it's a Shout-Out to Blue Seed or just a coincidence is unclear (the maple imagery in general does make a few other appearances in the Haruka franchise, along with the more traditional Cherry Blossoms).
 * Kyou and Ryou of Clannad both have Tomboyish Names that rhyme.
 * Yuna and Yuma Kashiwagi in Pani Poni Dash!.
 * Kirio and Kirika of Kamichama Karin. It's also worth noting that their father's name is Kirihiko.
 * Darry and Gimmy (puns on hidari and migi, Japanese for left and right, respectively) in Tengen Toppa Gurren Lagann.
 * Fuuka and Fumika Narutaki in Mahou Sensei Negima. Less obvious in translation, as the former's name is usually Anglicized as "Fuka".
 * In Rurouni Kenshin's Kyoto arc, we learn that Cool Big Sis Tae Sekihara has a twin sister named Sae.
 * The Half-Identical Twins in Kiddy Grade are named Tweedledum and Tweedledee (see Literature section above). There are also two Bishonen Sinistra and Dextera ("left" and "right" in Latin), who are not actually twins but look very much alike.
 * Angelic Layer has sisters Shōko and Shūko, although they, too, are not twins — Shuuko is older. This was lampshaded by their English voice actresses in the audio commentary, who wondered what kind of cruel parents their characters had.
 * A variation occurs in Fushigi Yuugi. While Amiboshi and Suboshi are known by their Seishi names and not their real ones, it is still worth noting that their Seishi names sound alike. Miboshi, however, is another story...
 * The Tachibana twins in Captain Tsubasa are named Masao and Kazuo.
 * The Dylandy twin brothers in Mobile Suit Gundam 00. The older twin is Neil, whose name means "cloud"; the younger twin is Lyle, and his name means "island".
 * Sarasa's and her twin Tatara's name from Basara sound rather similar.
 * Tatsuya and Kazuya from Touch. Taking it a step further, they are nicknamed Tacchan and Kacchan.
 * In and Yoh (Japanese for Yin and Yang) from Cos Prayers.
 * Marchiano's 12 Sisters in Coyote Ragtime Show. All twelve of them are named after the months of the year (though their relative ages [they're gynoids] are not the same as the order of the months). The three "youngest" sisters are October (Octo), November (Nove), and December (Dece).
 * from Chaos;Head.
 * Sailor Moon: Deimos and Phobos (Rei's pet crows) are both named for Mars' two moons. Phi and Chi (and Theta) are named for Greek letters. Lethe and Mnemosyne are named around the idea of memory.
 * Luki and Noki from DOGS Bullets and Carnage.
 * Raiga and Fuga from Fist of the North Star, who are modeled after Raijin and Fujin (the Twin Gods of Thunder and Wind in Japanese mythology).
 * The true identity of the Heavenly Empress is none other than.
 * Raoh's suspiciously similar elder brother Kaioh, although they're not exactly twins.
 * Nijuku and Sanju from Shoulder a Coffin Kuro, whose names are also contracted versions of the Japanese words for twenty-nine and thirty.
 * Zero and Ichiru Kiryu from Vampire Knight. 'Zero' literally means 'zero' and the 'ichi' in 'Ichiru' means 'one'.
 * Zero and Rei from Kurohime.
 * Hana (flower) and Ageha (butterfly) in Papillion.
 * Yanbo and Mabo from 20th Century Boys, though these seem to be nicknames.
 * Creepy Twins Hansel and Gretel from Black Lagoon.
 * Slayers has main character Lina and her (never-appearing) older sister Luna.
 * The Kongo Twins of Eyeshield 21 are named Agon and Unsui, which is all part of a very intricate pun:
 * Kongo-Rikishi are the two guardian statues seen at the entrance of Japanese Buddhist temples. The nicknames for these statues are "Agyo" and "Ungyo".
 * Symbolically, "a" represents birth/beginning since it's the first character of the Sanskrit alphabet and "Un" represents death/ending since it's the last character. Thus referring to something as an "A-Un relationship" is another way of saying it's harmonious and natural.
 * An "a" statue refers to a statue with an open mouth. An "un" statue is one with a closed mouth (usually frowning). Guess which twin is the quiet one and which one's the talker?
 * There is a yaoi manga called Twins Labyrinth (not about Twincest) where the twins are named Rin and Ren.
 * Tekkaman Blade has a main character and Evil Twin named Takaya and Shinya. Teknoman breaks the pun by renaming Shinya as Cain.
 * Mei and Kyu in Yu-Gi-Oh; "meikyu" means labyrinth. In the dub their names become Para and Dox.
 * Yu-Gi-Oh! 5D's gives Rua/Lua and Ruka/Luca, the dub keeps the alliteration with their Dub Name Change - Leo and Luna.
 * This sometimes happens in Magical Girl anime where the main character as two sidekicks/assistants/what have you. Examples include Posi and Nega from Creamy Mami and Pigu and Mogu from Fancy Lala (renamed Pog and Mog in the English dub, despite never being seen on TV).
 * Mipple and Mepple from the original Pretty Cure.
 * While not twins exactly, Ran, Miki, and Suu from Shugo Chara were named after the members of a Japanese singing group from the 1970s called Candies.
 * Shizuki and Yuzuki from Hekikai no AiON. Shizuki's name means "calm moon" and Yuzuki is "kind moon".
 * An episode of Pokémon features Forrest and Forrester. Their original names are Jiro ("second son") and Ichiro ("first son") respectively.
 * Risa and Riku from D.N.Angel.
 * Is It Wrong to Try to Pick Up Girls in a Dungeon? has the amazon sisters Tiona and Tione Hiryute, who regularly adventure together.
 * Is It Wrong to Try to Pick Up Girls in a Dungeon? has the amazon sisters Tiona and Tione Hiryute, who regularly adventure together.

Comic Books

 * In Marvel Comics, the Fenris twins Andreas and Andrea von Strucker; and mutants Jeanne-Marie and Jean-Paul Beaubier. Additionally, the latter twins' code names, Aurora and Northstar, are both astronomy-themed.
 * Twin sisters Dusk and Dawn of Noble Causes.
 * Dawn and Don Allen, the twin children of the second Flash. (One suspects their parents resorted to nicknames early on.)
 * Is this to do with accent? If so, then pronunciation would only be a problem if Barry and Iris spoke with some sort of Pacific Coast accent, which they presumably did not, seeing as how they were raised in the Midwest.
 * Albert Desmond and his "psychic" Evil Twin Alvin both went by Al.
 * Michael and Michelle Carter from Booster Gold, were given the masculine and feminine versions of the same name respectively.
 * Amusingly enough, Thompson and Thomson (originally Dupond and Dupont) from the Tintin comics are not twins. They're not even related, despite being identical except for the shapes of their mustaches. Dupond with a D has the slightly d-shaped one, and Dupont with a T has the slightly t-shaped one.
 * Tambi and Bambi Baker from Strangers in Paradise. (Real names: Mary Beth and Sara Beth.)
 * When you have a character who's an artificial intelligence named ONE, you can't REALLY act surprised when his twin, TWO, shows up. Or when he goes evil for that matter.
 * In Pre Crisis days, two of Clark Kent's neighbors in his apartment building were twin sisters April and May Marigold.
 * While not phonetically similar, the Teenage Mutant Ninja Turtles share themed names, as Splinter named them after Renaissance artists; Michelangelo, Donatello, Leonardo and Raphael.

Film

 * Parodied in the third Austin Powers with the twins Fook Mi and Foo Kyu.
 * Noreen and Doreen from Hairspray.
 * President Scroob's twin mistresses, Marlene and Charline, from Spaceballs.
 * Star Wars: Luke and Leia Skywalker, Ann and Tann Gella, Jaina and Jacen Solo.
 * Dawn and John from the second Care Bears movie.
 * Mia and Tia, the Miata twins from Cars.
 * Also Rusty and Dusty Rus Eze and Johnny and Jamie.
 * Flora and Fauna, the conjoined twins from The Addams Family.
 * In the sequel to the deliberately campy The Lost Skeleton of Cadavra, two characters who had been killed off turn out to have had identical twins. One of them merely shares the last two letters of his dead brother's name, but the other one has exactly the same name. When he's asked whether it ever caused confusion, he explains "We have different last names".

Literature
"Now with twins, I don't know what it is, but parents have a natural instinct to give them those soundalike, same-initial, cutesy names. "Hey, meet our twins, Timmy and Tommy." Once again, it's cute when they're four, but by ten they're in therapy. Each twin needs to have his own personality and that should start with the name. It should be unique in and of itself, and not dependent on the sibling. That's the healthiest thing you can do for them as parents. I can see different personalities already starting to develop in my boys. Gregory's the independent one, outgoing and daring and not afraid to try anything. Schmegory... well, he's got a few problems."
 * Tweedledee and Tweedledum of Alice in Wonderland.
 * In The Care Bears Adventure in Wonderland, the Wizard calls them simply "Dim" and "Dumb". This suggests that Tweedle might be a surname, much like Turanga or Mao. But these Tweedles still have their own theme: low intelligence.
 * Marilyn and Carolyn from The Baby-sitter's Club.
 * And later, when Abby joined the club, her twin was named Anna.
 * Which is rather funny, considering the Author admitted that Abby and Anna were called Lucy and Ethel in drafts, as naming the twins was the grand prize of a fan contest.
 * There are also twins named Mariah and Miranda in the girls' class at school.
 * Most twins featured in A Song of Ice and Fire have rhyming names, including Errik and Arrik and Aemon and Aegon.
 * Averted with main characters Cersei and Jaime and their cousins Willem and Martyn, though.
 * Alanna, herself a twin, from Tamora Pierce's Tortall Media Franchise, named her twins Alan and Alianne. Alan was the name of her late father, as well as the name she used while posing as a boy during her knight training. However, in an aversion, her twin's name was Thom. Which itself means twin.
 * Rhyme and Reason from The Phantom Tollbooth, on top of the fact that most characters in the story are just about the definition of Anthropomorphic Personification.
 * Sara and Tara Leighton from Tales of MU.
 * Adele and Eleda from The Truth Tellers Tale. The mirror-image names are a reference to their Different As Night and Day personalities, but the author also gave everyone else in their family palindromic names.
 * Tira and Kira from the Belgariad and prequels, and even more so once they get their wizard names: Beltira and Belkira.
 * From Discworld "Pyramids", a pair of twins named Ptaclusp IIa and Ptaclusp IIb (their father being simply Ptaclusp). They're actually pronounced "two-ay" and "two-bee".
 * Happens in J. R. R. Tolkien's Middle-earth (Silmarillion, The Lord of the Rings, etc), although here it is only part of the larger tradition of family members commonly being given similar names: Amrod and Amras (Feanor's twin sons, who were also both named Ambarussa); Haleth and Haldar, the twin children of the human chieftain Haldad; Dior's twin sons Elured and Elurin; twins Elrond and Elros; Elladan und Elrohir (Elrond's twin sons); Folcred and Fastred (twin sons of a king of Rohan).
 * Also happens in Narnia, specifically Archenland, which may be connected given C.S. Lewis' and Tolkien's friendship and their influence on each other. Archenland is known for sets of twins with similar names such as Cole and Colin, Corin and Cor, and Dar and Darrin. In The Horse and His Boy, this is lampshaded as a naming tradition.
 * A naming tradition for brothers. Of the three pairs mentioned, only Cor and Corin are known to be twins.
 * In the Cambridge Latin Course, there are a pair of twins named Loquax and Anti-Loquax. This sort of thing may have been relatively common practise among the ancient Romans.
 * Anatole, a French mouse who is also a cheese expert, has three sets of twins (sextuplets?): Paul & Paulette, Claude & Claudette, and Georges & Georgette.
 * David Weber does this in the Honor Harrington series with the Masadan ships in Honor of the Queen.
 * Power and Dominion
 * Throne and Principality
 * Angel and Archangel
 * David and Solomon
 * Cherubim and Seraphim
 * Most of these are from the medieval celestial hierarchy; in decreasing order, Seraphim, Cherubim, Thrones, Dominions, (Virtues,) Powers, Principalities, Archangels, and mere Angels.
 * Shakespeare's The Comedy of Errors features two sets of twins who both have the same name. This is somewhat justified in that both pairs were raised separately.
 * From Harry Potter: Padma & Parvati Patil and Lorcan & Lysander Scamander . Though not twins, Sirius and Regulus Black are named after stars, as are their cousins Andromeda and Bellatrix (would that make Narcissa the Odd Name Out?).
 * Averted though, with Fred and George Weasley.
 * Their uncles (who could be twins) were named Fabian and Gideon, overlapping with a different trope.
 * This troper believes that Percy's name might originally have been meant to be something beginning with D or E, as this would give (including their father) in order: Arthur, Bill, Charlie (nothing for D or E, maybe Percy was meant to be here), Fred and George. And then completely messed up at the end with Ron and Ginny.
 * Daisy and Demi in Little Women, named after their parents Margaret (Meg) and John.
 * Sent up in Ray Romano's book Everything And A Kite:


 * In BattleTech, a renegade group of Clan Jade Falcon scientists created children that were genetic clones of their war hero, Aidan Pryde. All named children in the book had anagrams of Aidan for their names.
 * East of Eden, which draws heavily on the Cain and Abel story from The Bible, first depicts the relationship with two brothers (not twins) named Charles and Adam. When Adam's twin sons are born, he considers actually naming them Cain and Abel, but a neighbor tells him that would be asking for trouble. He goes with Caleb (Cal) and Aaron (Aron) instead. Of course, the relationship repeats anyway.
 * V. C. Andrews has done this a few times: Carrie and Cory Dollanganger, Deirdre and Darren Marquet, Cade and Adrian Eaton, Justin and Austin in the "Secrets" series. Averted with Celeste and Noble, Cary and Laura, Ruby and Gisselle, and both sets of Pierre and Jean Dumas.
 * Over the last two books in the Teenage Worrier series, Letty's classmate gets pregnant with twins and is forced to drop out of school. She names them Barin and Rabina, which Letty finds funny, but turns out to be significant because
 * Bradley and Brian in the Calendar Mysteries series.

Live-Action TV

 * Arrested Development has identical twins named "George Oscar" and, presumably, "Oscar George".
 * There's also Maeby and the non-existent "Surely".
 * Averted with the other Bluth twins, Michael and Lindsay.
 * Northern Exposure: Joel Fleischman's twin brother Jules show up for one episode.
 * 7th Heaven has the Camden babies Sam and Dave. Yes, that's a theme, Sam and Dave are the musical duo that sang "Soul Man".
 * Although they're not actually twins, the Identical Stranger nurse who replaced Laverne Roberts in Scrubs is called Shirley. As in Laverne and Shirley.
 * Miss Piggy's nephews Andy and Randy Pig in Muppets Tonight.
 * Porter and Preston on Desperate Housewives. Their siblings are Parker and Penny.
 * Beverly Hills, 90210 twins: Brandon and Brenda.
 * Power Rangers RPM has Half-Identical Twins Gem and Gemma. Likely justified as being codenames given to them by the government think tank they were abducted into - their friend in the tank was known as "Dr. K" and specifically could not remember her real name.
 * No twins in Wonderfalls, but an example close to the Ben 10 quote above: The members of the Tyler family are named Karen, Darrin, Sharon, Aaron... and Jaye.
 * In an episode of Wings, Lowell is asked to name his pregnant cousin's child, and she has twins, which gives him some trouble, since what with Lowell being what he is, he thinks the names have to rhyme. Not long after, Joe jokingly throws out Nancy and Fancy, which Lowell immediately loves, leading to the line: "If in 25 years a very large man named Fancy Mather shows up to kill you, this is why."
 * From Newhart: "I'm Larry, this is my brother Darryl, and this is my other brother Darryl."
 * Privileged takes the "thematically similar" route with Rose and Sage.
 * Popular featured the Tuna twins, April and May.
 * In the second series of ITV crime drama Whitechapel, Ronnie Kray's twin sons, Jimmy and Johnny Kray.
 * The Amazing Race had the teams of Derek & Drew (Season 3) and Kami & Karli (Season 5).
 * Utterly averted on The West Wing: Andy's twins are named by two different people, for completely different reasons, and in fact not even at the same time.
 * Towards the end of Dark Angel, it was revealed that the heroine Max had a long-lost twin sister named Sam.
 * The Doctor Who serial The Twin Dilemma featured twins called Romulus and Remus. Unfortunately the actors playing them had difficulty pronouncing the letter "R".

Music

 * In Vocaloid, twins Rin and Len respectably mean "right" and "left". Also, their last name Kagamine includes the character for "mirror", representing their mirror representations of each other.

Video Games

 * Mio and Mayu from Fatal Frame II: Crimson Butterfly. The story also includes twins named Sae and Yae, Azami and Akane, and Itsuki and Mutsuki. (The entire game is essentially about a village that considers twins to be one spirit.)
 * Palom and Porom in Final Fantasy IV.
 * Hurdy and Gurdy in Final Fantasy XII.
 * As well as Ai and Yu from Final Fantasy Unlimited. In addition to being homophones for I and You, Ai can mean "love, affection, friendly" and "indigo" while Yu can mean "happy, pleased" or "jade".
 * Lucas and Claus in Mother 3. They were actually named after the protagonists of Agota Kristof's novel The Notebook.
 * Also, Lucas and Claus are anagrams of each other. Not that you can tell when they're written in katakana...
 * Lei-Lei and Ling-Ling, twin Chinese girls who use a Dangerous Forbidden Technique to fuse into a Chinese Vampire in Darkstalkers.
 * Solid and Liquid Snake (of Metal Gear Solid) are twins named after opposing states of matter, while the third brother is named Solidus. This has led to jokes (and more than a few Urban Legends Of Zelda) that there may be a fourth Gas Snake out there somewhere (and knowing Kojima this may very well be possible).
 * That's not the only suggested name for a hypothetical Separated at Birth twin. See the Wikipedia article List of states of matter for a pretty conclusive list. Plasma Snake? Supercritical Fluid Snake? Colloid Snake? Electron-degenerate Matter Snake? Bose-Einsteinium Condensate Snake?
 * Twins Chinami and Ayame of Gyakuten Saiban 3 have flower themed names. Their names in the English Phoenix Wright: Ace Attorney: Trials and Tribulations are.
 * Ariel and Mariel in Summon Night: Swordcraft Story not only have similar names, but dress the same (though in different colors).
 * At one point Mariel refers to Ariel as "big sister", but as they are specifically called twins, this is probably a title of respect.
 * Kat and Ana of Wario Ware. Yes, they're ninjas.
 * But are they better?
 * Dante and Vergil from Devil May Cry, named after the two protagonists of the Divine Comedy.
 * Hannah and Hinnah from The Last Remnant.
 * Vent & Aile of Mega Man ZX. French for "Wind" & "Wing", respectively.
 * Though they aren't twins so much as alternate universe equivalents of each other (or something).
 * And of course Rock & Roll from the original. They're not quite twins, as Roll was built a bit later, but it still fits.
 * There's also Crea and Prea (create and pray) from Mega Man Zero, named by Alouette.
 * And Battle Network has the Hikari twins, Netto (熱斗) and Saito (彩斗). Both names share a kanji character and are both puns on computer terms - "netto" (ネット) is short for "intaanetto" (インターネット), Japanese for "Internet", and "saito" (サイト) means "web site". In the English version, their names were changed to Lan and Hub, both computer terms.
 * Ingram & Viletta (a corruption of Baretta) from Super Robot Wars, both named after guns. They're not exactly twins, though.
 * Billy and Jimmy Lee from the Double Dragon series. The NES version of the third game infamously misspelled the former's name as "Bimmy" in the 2-Player version of the opening intro.
 * Their counterparts in River City Ransom are named Randy and Andy, the Dragon Twins. In the Japanese Kunio-kun games, their names are Ryūichi ("first dragon") and Ryūji ("second dragon") Hattori.
 * Vocaloid has Rin and Len Kagamine. Their names are a pun on the words "right" and "left", respectively.
 * The Edison twins Jed and Ned in The Day of the Tentacle.
 * The whole Edison family gets in on this. In total, there are Dr. Fred, Weird Ed, Edna, Dead Cousin Ted, Red, Ned, Jed, Zed, Zedna and Ved (The latter three being in the far future, explaining their use of Xtreme Kool Letterz.)
 * Serena and Sera (Suu and Muu in the Japanese version) from Rune Factory 2.
 * Bubble Bobble games: Bub(blun/by) and Bob(blun/by), the main protagonists in the games. And Coro(ron/n) and Kulu(lun/n), that female Beta Couple in Bubble Symphony.
 * In Bubble Bobble Plus (Wii Ware), Pab and Peb, a different female Beta Couple. (refer to Title Operations Guide in Wii Shop Channel)
 * Maori's twin sisters Koito and Kouta in Arcana Heart. It's more obvious in Japanese, their names both start with the kanji for 'small'.
 * Gouken (Strong Fist) and Gouki (Strong Demon) from the Street Fighter series, although this is Lost in Translation due to the latter becoming "Akuma" in the international versions.
 * While the cast of Eternal Sonata falls under something more like Population Theme Naming (so that March and Salsa aren't particularly noteworthy), a better example, similar to Kat and Ana above, can be found in Tenuto's fields early in the game: a pair of twin girls named Sop and Rano.
 * Big Bang Beat's Kendo and Kyudo Nakanishi are named for their respective fighting styles - Kendo is the "way of the sword" (practiced with the 'shinai' that Kendo uses as well as actual swords), and Kyudo is "the way of the bow", or archery.
 * See Chaos;Head in the "Anime" folder above. (Warning: it's a Spoiler.)
 * Eirika and Ephraim of Fire Emblem 8.
 * Redmond and Blutarch in the backstory for Team Fortress 2 just so happens to be the founders of the rivalling companies Reliable Excavation Demolition and Builder's League United, aka RED and BLU. You will also notice that the first three letters of the brothers' names syncronize pretty well with the acronyms for their companies.
 * Miho and Maho Shirayuki of Tokimeki Memorial 2. Maho's name is especially ironic, in that she's the "shadow sister" of the two, while the Kanji "Ma" (真) of her name means "Truth" in Japanese.
 * Single-Minded Twins Timmy and Tommy from Animal Crossing series.
 * Many members of the Twins trainer class in the Pokémon series use this trope, especially in the Gen II games. Twins Ann & Anne are probably the most extreme example. They also tend to use identical, similar, or complementary Pokémon.
 * Ami and Mami Futami from The Idolmaster franchise.

Web Animation

 * Doreen and Maureen. And their mum Noreen. Then there are their parody counterparts Meryl, Beryl and Cheryl. (who have saggy arses instead of saggy breasts)

Web Comics

 * Nale and Elan in The Order of the Stick.
 * In The Inexplicable Adventures of Bob, Bob nicknames Molly's clone/sister Galatea "Golly", leading Molly to comment, "We're a Little Richard song!"
 * Also not exactly twins, but... Ellen and Elliot from El Goonish Shive. Justified as Elliot coined the name by feminizing his own when he was first turned into a girl.
 * Thoss and Thlassa in Juathuur.
 * Sally and Sammy in LnM. Their nicknames for each other, L and M, come from being the only letters in their names that are different.
 * Sally and Sammy in LnM. Their nicknames for each other, L and M, come from being the only letters in their names that are different.

Web Original

 * Survival of the Fittest v4's Ishida twins, Reiko and Reika.
 * Subverted in We're Alive. Latch and Scratch are nicknames.
 * In Red vs. Blue, there are a pair of twin Freelancers codenamed North Dakota and South Dakota.
 * In Fenspace, "Mikuru Asahina" is a gynoid double for her creator, who is named "Kurumi" (spelled with the same kanji as "Mikuru" in a different order).

Western Animation

 * Azula's elderly Creepy Twin teachers Lo and Li from Avatar: The Last Airbender, playing off a Chinese phrase that means "to mumble endlessly".
 * Sherri and Terri from The Simpsons. Patty and Selma are an odd exception to the theme naming rule.
 * Kim Possible's younger brothers, the twins Jim and Tim Possible. Shego's twin brothers are Wego. Both of them.
 * Also their father James "Jim" Possible has a(non-twin) brother, Slim. Plus mention was made of a turn-of-the-century member of the family, Mim(short for Miriam). The Possible family got a lot of mileage out of that rhyme scheme.
 * Phil and Lil of Rugrats.
 * Although, in an aversion, their full names are Phillip and Lillian.
 * And then un-averted, as it was probably designed that way so that their shortened names would rhyme.
 * Tomax and Xamot, the twin leaders of COBRA's Crimson Guard, in G.I. Joe.
 * Wilykit and Wilykat from Thundercats and Thundercats 2011.
 * Thematic example with Nancy and Drew Quymn in The Venture Bros. They are, of course, named after Nancy Drew.
 * Tessa and Vanessa of Pepper Ann. Their Day In The Limelight episode "Vanessa Less Tessa" has a Show Within a Show with protagonists Gina and Tina.
 * Adam and Adora from He-Man and the Masters of the Universe/She Ra Princess of Power.
 * Also true of their superpowered counterparts, He-Man and She-Ra.
 * Tommy and Timmy from Arthur.
 * Ben 10 had these. Their introduction? "I'm Andy!/And I'm Mandy! (together) We're twins!"
 * Ben and Gwen (and, as the page trope says, Ken, Gwen's lesser-known older brother) fit this trope although they aren't twins. They were born on the same day, however.
 * Ben's last name is Tennyson. As in "Ben Tennyson. Gwen also shares his last name. Kevin's last name, however is Levin... as in "Kevin Eleven". Yup.
 * Kevin's middle name is eventually revealed to be Ethan, making his actual name Kevin E. Levin. Even Ben thinks it's too much.
 * Which is a subversion. Why couldn't it be Evan?
 * Camp Lazlo provides an interesting subversion. Of the loon twins, the most commonly referred-to one is "Ping" which makes you think the other's name would be "Pong". In actuality, though, the first is named "Ping Pong" and the other is named "Dave". It is, however, played straight with Chip and Skip, the dung beetle twins.
 * Huey, Dewey, and Louie, the nephews of Donald Duck. They rhyme without sharing any letter combinations.
 * Although they only appear in the comics, there's also Daisy's nieces April, May, and June.
 * The Proud Family had fraternal twin babies BeBe and CeCe, which not only rhyme, but are a reference to Gospel music artists BeBe and CeCe Winans, a brother and sister duet group.
 * In Batman Beyond: Return of the Joker, a pair of twins act as Co-Dragons, and are known collectively as "Dee-Dee". Their real names, revealed at the end, are Delia & Deidre Dennis.
 * 6teen's clones are named Kirsten, Kristen and Chrissy.
 * Alexander and Alexandra Cabot on Josie and the Pussy Cats.
 * The original names for the Lamborghini Twins in Transformers were Sideswipe and Spinout.
 * Spinout become Sunstreaker, which is still a bit similuar... Both can be abbreviated to SS.
 * And now we have Jetstorm and Jetfire, the...jet twins.
 * Thomas the Tank Engine has this in spades. Bill and Ben, Donald and Douglas, Mighty and Mac...
 * Averted with Annie and Clarabel
 * Umm... Annie is short for Anabel.
 * Yin Yang Yo!: Yin and Yang anyone?
 * The Fairly OddParents: Tad and Chad, Wanda and Blonda, Tommy and Tammy.
 * I'm pretty sure Tad and Chad aren't actually related. Tommy and Tammy also aren't confirmed to be twins, though it's quite possible.
 * Brits of a certain age will remember Molly and Polly from Pigeon Street ("Molly and Polly, they're two of a kind / They look both the same when they're seen from behind / But when they turn round then it's easy to see / Who's Molly with an M and Polly with a P").
 * Single-Minded Twins Hip and Hop Koopa in The Adventures of Super Mario Bros 3.
 * Ang and Ling Jouyan in Legend of the Dragon—because Ang is Yang and Ling is Yin.
 * Robin and Rosie in the British stop-motion series Cockleshell Bay.
 * In Season 3, episode 14, of The Boondocks it turns out Uncle Ruckus' siblings are named Daryl and Darrell.
 * Tugs and Hugs from Care Bears.
 * Brothers Flim and Flam of the My Little Pony Friendship Is Magic episode "The Super Speedy Cider Squeezy 6000".

Real Life

 * Behind the Name has a page on such theme naming.
 * Kishimoto Masashi, author of Naruto, has a twin brother Kishimoto Seishi, author of 666Satan. The last character in both names is the same.
 * The Social Security list of popular names for twins shows that this is distinctly a case of Truth in Television. Nearly all of them rhyme, alliterate, fit into a theme, or are names of famous siblings.
 * This could be a case of statistics not telling the whole truth. It makes sense that two similar names would be used on more sets of twins than two unrelated names. And the numbers aren't that big- less than two percent of the sets of twins born per year have name sets on that list.
 * Mark Antony and Cleopatra's twins, Alexander Helios and Cleopatra Selene. Helios is the god of the sun; Selene is the goddess of the moon.
 * The famous newspaper advice columnists Abigail Van Buren and Ann Landers were identical twins. Their real names are/were Pauline Esther (the original Abby—the current columnist is her daughter) and Esther Pauline (the late Ann).
 * New Zealand had a case where the parents wanted to name their twins Fish and Chips. This was blocked by the courts. The courts did allow a request from another set of parents to call their twins Benson and Hedges. More details can be seen here
 * Anyone who has a remote knowledge about the stereotypes about New Zealanders can clearly see why they weren't allowed to name their kids fish and chips.
 * The twin grandsons of Earl Mountbatten of Burma, who were with him when the IRA blew up his boat in 1979, were Nicholas Timothy Knatchbull (who died) and Timothy Nicholas Knatchbull (who survived).
 * The Islamic version of Cain and Abel, Habil and Kabil.
 * Jennifer Lopez and Marc Anthony named their twin children Max and Emme. As in Dragon Tales.
 * It was apparently somewhat common for Romans to name one kid Xxxx and the other Anti-Xxxx. In other words, one kid was defined as not being the other one.
 * The Romans were very uncreative about naming in general, so this probably wouldn't have stood out.
 * Rami Malek (known for his role in The Pacific and Night at the Museum, just in case if you don't recognize him) has a twin brother named Sami Malek.
 * Actress Jill Hennessey has a twin sister named Jacqueline. In other words, "Jack" and "Jill".
 * Ronnie and Reggie Kray, notorious London gangsters.
 * Back in the Middle Ages, "Adam and Eve" were common as twin names. Fridge Logic makes you wonder why parents were naming siblings after a married couple, however, until you realize that Eve was a clone created from cells taken from Adam's side, and therefore both were genetic identical twins. (Not that anyone in the Middle Ages would have thought of that.)
 * Legendary Mixed Martial Arts fighters and identical twins Antônio Rodrigo Nogueira and Antônio Rogério Nogueira, with only their middle names being slightly different. To avoid confusion, most fans refer to them as "Big Nog" and "Lil Nog" (given that Rogério cuts weight to fight at light heavyweight and his "big brother" doesn't), or less commonly, "Diet Nog" (Rogério has even been seen wearing a Diet Nog t-shirt). They've even been referred as this by the announcers on TV (more for Lil Nog, Rodrigo can also be differentiated by his nickname Minotauro).
 * Funny enough it's subverted in Danish culture. The strange thing about this is that many, if not most, normal siblings have similar sounding names but in case of twins, parents are apparently obeying the advices of child psychology.
 * Averted with Bill and Tom Kaulitz—though, amusingly enough, the name Tom means, simply, "Twin".
 * Averted in a daycare this troper worked at, where the two sets of twins had names that were nothing like each other at all.
 * Totally played straight in China, where not only twins are subjects of the trope, but entire families. Chinese names are usually two-part names, with two elements. In twins and often in non-twinned siblings, the same element is often used for either the first or second part of the given name, and then different elements used for the other. Well known examples include Madam Chiang Kai-shek, whose birth name was Soong May-Ling. Her sisters were Soong Ai-Ling and Soong Ching-Ling.
 * LaShawn Maurkice Pouncey and James Michael Pouncey (centers from the Pittsburgh Steelers and Miami Dolphins, respectively) seem like an aversion, until you realize both use their middle lames, Maurkice and Mike.