Clark Kent: ...Then you don't know me as well as you think.
When an established existing medium ventures into the Expanded Universe, writers will often rely heavily on familiar characters and past storylines from the official canon to ensure that fans of the original material are happy. Unlike the original canon, however, an "expanded universe" adaptation also gives the writers freedom to introduce new, "never before seen" characters, as the production staff enjoys their newfound liberation from whatever codes and limitations ruled the original work.
Often, these new characters will be added to fill a particular need in the new story, and add some degree of novelty to attract readers/watchers. Frequently, they'll also fill some gap in the current cast, such as adding a female character to an all-male cast (or adding a second female where there was only one before), or adding some other element of diversity, be it racial, geographic, sexual, or simply personality. This can spark new conflicts and adventures that wouldn't otherwise occur under the limitations of the "conventional" cast and series format one of the main points of "expanded universe" fiction to begin with.
If a fanfic or a spinoff is created from a work of fiction and it is full of original characters, it may invert this by including some characters from canon. Typically, these characters will not be killed off even if original characters do die for the sake of preserving it.
Depending on how well the character fits into the adaptation or how much the fans like the character, Canon Foreigners can either be much beloved or much hated, and if popular enough, may be Ret Canoned into the official canon where they are known as Canon Immigrants.
Compare Original Generation characters, who are Canon Foreigners to several canons at once in a Crossover plot, or Canon Character All Along, when a supposedly new character is later revealed to be a well-established character within a canon.
Contrast Adapted Out, where a character in the source material is omitted in the adaptation.
See God-Created Canon Foreigner when this character comes from the original creator.
- The Big Finish Doctor Who audio plays had Erimem (companion to the Fifth Doctor), Evelyn Smythe (companion to the Sixth Doctor), Hex and Raine Creevey (both companions to the Seventh Doctor), Charley Pollard (Eighth and later, at least from her point of view, Sixth Doctor companion), C'rizz, Samson and Gemma Griffen, Lucie Miller, and Mary Shelley (all companions to the Eighth Doctor) all slotting in around gaps in the timeline of the TV series.
- The Blake's 7 Liberator Chronicles introduce the Auron scientist Gustav Nyrron, who boards the Liberator in "Solitude" and is promptly dumped at Avon's insistence. He returns in later episodes.
- Although, like the comics, the Star Trek Expanded Universe novels seldom used original recurring characters in the late '80s-early '90s, it was the norm by the late '90s and the modern novels make regular use of Canon Foreigner characters, and there are whole book series that aren't based on the shows and are populated mostly by Canon Foreigners or Ascended Extra characters (e.g. Titan, Vanguard, Corps of Engineers, IKS Gorkon, and Department of Temporal Investigations). In spite of their popularity and critical importance in the Expanded Universe, neither Captain Calhoun nor Elias Vaughn has ever been featured in canonical Star Trek. Although one major character created for the Star Trek: Deep Space Nine novels set after the series was intentionally based on a certain extra who was only seen from the back in a canon episode.
- Virgin Publishing's Doctor Who New Adventures novels created a number of new companions for the Seventh Doctor, including Bernice Summerfield, Roz Forrester and Chris Cwej. Virgin's Doctor Who Missing Adventures had Grant Markham, a short-lived companion to the Sixth Doctor. BBC Books' Eighth Doctor Adventures range had Samantha Jones, Fitz Kreiner, Compassion, Anji Kapoor, and Trix MacMillan. Innumerable new villains have occurred in the Doctor Who Expanded Universe. One, Faction Paradox, the Evil Counterpart to the Time Lords, spun off into its own sub-universe of audio plays, comics and novels. They began in novels.
- Hotblack Desiato and Disaster Area in The Restaurant at the End of the Universe and subsequently the TV version of The Hitchhiker's Guide to the Galaxy were created to replace the sequence with the Haggunenons in the radio series, which was mostly written by John Lloyd, and therefore Douglas Adams didn't feel was "his".
- The first StarCraft Expanded Universe novel, Liberty's Crusade, was a Pragmatic Adaptation of the first game's Terran campaign. Its viewpoint character is a journalist named Michael Liberty who is embedded with then-Colonel Edmund Duke's Alpha Squadron (partly to hide him from Confederate magnates he pissed off with his previous story). With the exception of Queen of Blades (which covers the SC Zerg campaign from Jim Raynor's viewpoint) and Speed of Darkness (which focuses on a group of Confederate Marines on Mar Sara who were Heroes of Another Story to the Player Character of the Terran campaignnote ), the other books don't touch the game campaigns, inevitably creating dozens of Canon Foreigners.
- Inevitable in the Star Wars Expanded Universe, since its timeline spans roughly 100,000 years of which the movies comprise about forty.
- Sonic the Hedgehog
- Another Note expands on the LABB Murder case mentioned briefly in Death Note, and introduces L's Evil Twin, Beyond Birthday.
- The Ultima novels introduce Baron Amrik, Ariel, and Sharon, in Ultima Underworld, Cindy, Howard, Philipps, and Zole, in The Cabal of Zole the Mage, Roto, in Adventure Novels: Ultima I, Gauta, in Adventure Novels: Ultima IV, and Aya Mizugami, Takuma Hiura, and Kitasato, the Spirit of Wind, in Monstrous Metamorphosis.
- Many Waters has its protagonists go back to Bible Times and stay with Noah and his family; aside from his three sons and their wives, he is depicted having four daughters. There are also other secondary characters who live in there.
- The Resident Evil novelization by S.D. Perry introduces Trent, a Mysterious Benefactor of sorts. At the time the games had little, if anything, tying them together, so Trent was created as a common point between the books to fill the holes and give them an overarching narrative.
- While several TNA contracted wrestlers had matches in AAA, the luchador known as Border Patrol specifically represented TNA yet had never worked for it. TNA also has a long running gimmick called "Suicide", to which AAA gave a counterpart in Australian Suicide, who kept the name even after Suicide was renamed Manik.
- The Adventures of Superman introduced Jimmy Olsen, Inspector Henderson, Kryptonite and the names "Daily Planet" and "Perry White."
- The BBC Radio 4 series The Rivals adds Inspector Lestrade from the Sherlock Holmes books to the adventures of various other Victorian detectives, creating a sort of Shared Universe from unrelated stories.
- Nathaniel Ward of the H. P. Lovecraft Historical Society's projects is an unusual case. Originally created as a Call of Cthulhu RPG character, the hosts of the Dark Adventure Radio Theatre series later spoke of him as the hero of a separate program within the audio adaptations' own miniature universe. Eventually, Ward featured in the HPLHS's film adaptation of The Whisperer in Darkness, a monograph, and three of the Society's other radio dramas to date (The Dreams in the Witch House, Imprisoned with the Pharaohs, and Dagon: War of Worlds). He's implied to have an epic life beyond even the aforementioned titles.
- While the characters of the software are guests for New Dynamic English, there are also new characters being interviewed. There's also Elizabeth Moore, who's the host of Functioning in Business, and can be heard socializing with Max and Kathy in the Story Interludes.
- Whenever Clue comes out with an expanded version or spinoff based around Boddy Mansion (as opposed to say, Star Wars or The Simpsons) it seems traditional to add a bottle of poison as a weapon, as well as the appearances of Madam Rose, Sgt. Grey, M. Brunette, and Miss Peach as extra characters.
- The mage/planeswalker Jodah in Magic: The Gathering was created by Jeff Grub for the novelizations of the plot of The Dark and the Ice Age cycle of books, created in 1999 (where the sets were created in 1994-5). He'd prove popular enough to get an Avenger card in Planar Chaos.
- The Neon Genesis Evangelion RPG game The NERV White Paper introduced Maria Vincennes, a female EVA pilot from America.
- The Most Happy Fella, adapted from the straight play They Knew What They Wanted, built the comic Beta Couple of Cleo and Herman out of whole cloth, and gave Tony a sister Marie to object to his marriage. (In the original play, the objector is the Catholic padre; also, Amy jokingly refers to herself at one point as 'Cleo', playing off Antony and Cleopatra.)
- Several characters in As You Like It (which was Shakespeare's adaptation of the Thomas Lodge novel Rosalynde), most importantly Touchstone and Jacques (of "All the world's a stage" fame). The rest of the Canon Foreigners in the story are all related to them in some way: Jacques, being a cynical philosopher, gets a scene where he plays off the idealistic, music-loving "Amiens", while Touchstone's subplot necessitates the inclusion of his love interest, "Audrey, a country wench", a country priest named "Oliver Mar-Text", and "William", Audrey's ex-boyfriend.
- Swiss Miss from Spider-Man: Turn Off the Dark. Within the actual story, it's more or less acknowledged that she was created to add a female villain to Spider-Man's otherwise male rogue's gallery.
- A lot of characters in the Sera Myu musicals. Sailor Astarte, Space Knight, Lemures Baba, a whole bunch of new Shadow Galactica members...it'd take too long to name every new character introduced.
- The Tsukiuta series tends to have some of these in every entry. There are several recurring actors who have played original characters in multiple series entries, particularly Sean Suzuki, who has been in 5 of the 8 entries so far, playing a total of 7 different characters.
- In Disney Theme Parks, Star Tours introduces the Star Tours travel agency, the StarSpeeder 3000, the Tzarina luxury yacht, and a third Death Star, retconned as a worldcraft habitation sphere. Star Tours: The Adventures Continue introduces Ace the AC-38 droid, the StarSpeeder 1000, and Spaceport THX1138. The G2 repair droids, G2-4T and G2-9T, and Rex, the RX-24 droid, appeared at both rides. In Tokyo Disneyland, the max-W 100, P-6, and S-4 PanaRobo droids are manufactured by Matsushita Electric (Panasonic), the F series repair droid F-24 appeared at the first ride, the F-25 droid appeared at both rides, and the RX-Series pilot droid HHG-RX appeared in The Adventures Continue.
- At Universal Studios:
- E.T. Adventure shows all of E.T.'s friends that weren't shown in the film or any of its spin-off material, including Tikli, Orbidon, and Magdol.
- Kung Fu Panda Adventure features Kang, a villainous wolf pirate determined to stop the heroes from achieving their goal.
- Lord Darkenon, the villain of Poseidon's Fury, is not a part of any form of Greek mythology, instead being a character created just for the attraction.
- Star Trek Adventure introduced new Federation recruits, a Klingon crew, the Preceptors, and the planet Akumal 7.
- The T-1000000 or "T-One Million" in Terminator 2 3-D: Battle Across Time, making a cameo in the Nuclear Twilight comic.
- EVAC was created just for Transformers: The Ride, servicing as the Autobot that primarily deals with evacuation matters, as his name would suggest.
- The Trendmasters King of the Monsters Godzilla Force toyline has Godzilla Force, and its members David Easton, Peter Richards, Margaret O'Brien, and Michael Van Horn, a group of human commandos wearing Power Rangers style helmets, based on G-Force from Godzilla vs. Mechagodzilla II. Both groups fly a Garuda ship.
- Kenner's Super Powers Collection contained a few characters not seen in either The DCU or the Super Friends TV series. Among the new characters were heroes named Golden Pharaoh and Cyclotron, as well as an Apokoliptian assassin named Silicon.
- The Pink Shogunzord from Mighty Morphin' Power Rangers only exists in the toy line, as Ninja Sentai Kakuranger, the show Season 3 of MMPR was adapted from, did not feature a Pink Ranger. This caused a bit of a continuity error in the show, since the fact that the Shogun Ultrazord was filmed by using the toys meant that the Ultrazord's right arm would inexplicably change from white to pink depending on the shot.
- Around the time of the first Hulk movie, ToyBiz launched a series called "Hulk Classics" (a companion to their Marvel Legends, Spider-Man Classics, X-Men Clasics and Fantastic Four Classics lines), which featured various characters from across the history of the comic. The major exception was Mecha-Hulk, a robotic Hulk piloted by the Gremlin. Despite the suit never having appeared in the comics (even though the Gremlin did) Mecha-Hulk proved to be a huge hit with collectors.
- Likewise, the most sought after figure from the Fantastic Four (2005) movie line is the Doombot, a character who didn't even appear in the film (and whose design is totally different in the comics).
- The toy line for Power Rangers in Space contained a Zord named Silver Titanus, who appeared in neither the show itself, nor Denji Sentai Megaranger, the Japanese series it was adapted from.
- As mentioned in the Live-Action TV section, the Titanium Ranger from Power Rangers Lightspeed Rescue did not exist in Rescue Sentai GoGoFive. Adding to that, the Titanium Ranger had a toy-exclusive Zord called the Titanium Land Crawler, which did not appear in either TV show.
- The toy line for Power Rangers RPM included the Mammoth Ranger, the T-Rex Ranger, and the Triceratops Ranger. None of these characters ever appeared in the show, but the Paleozords they were modeled after did.
- The Power Rangers Dino Charge toyline had a few exclusive Zords that didn't appear in either the TV series or its source material — the latter justifying it by saying that the "auxiliary" dinosaurs lost their physical form in the battle against the Big Bad at the end of the dinosaur era.
- Donovan Corbett in Street Fighter: The Later Years
- Lewis Lovhaug is the White Zeo Ranger.
- The Richard E. Grant Ninth Doctor from the Doctor Who web animation Scream of the Shalka, and his companion Alison Cheney.
- Pokemon Digimon Mon Wars: While set in the Pokémon anime, characters from Pokémon Adventures and the games themselves may appear, even though they had yet to show up in the anime. Same could be said on the Digimon with characters outside Digimon Adventure.
- Ultra Fast Pony is an abridged series that nevertheless has a few original characters thanks to creative editing. There's Snuggle Berry, who's referred to a few times but never appears on-screen—and dies in the same episode she was introduced in. There's also Mutation: in UFP she's a separate character, but in the original canon she was just a shared secret identity.
- The Glass Scientists keeps a lot of characters from The Strange Case of Dr. Jekyll and Mr. Hyde and other victorian novels, but Jasper, a werewolf Audience Surrogate, is a new addition.
- The Transformers: Combiner Wars: Maxima is created by the Machinima team to be an original entity in their series who wasn't present in the comics the show adapts from.
- DSBT InsaniT: ???'s Guardromon Mooks and Tyrannomon are from Digimon. Killdra even references this.
Killdra: Thats copyright infringement. You don't have the license to use trademarked characters like those.
- Dreamscape: Vampire Lord comes from Yu-Gi-Oh!.