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Developer(s)Toby Fox
Publisher(s)Toby Fox
Reveal dateJune 25, 2013
Release dateSeptember 15, 2015 (Original PC release)
Platform(s)Microsoft Windows
PlayStation 4
PlayStation Vita
Nintendo Switch
Xbox One
External link(s)Official site
Related articles on Fanlore.

Spoiler Warning: This article or section may contain spoilers. If this bothers you, proceed with caution.

Undertale is a 2015 indie video game developed by Toby Fox. It is a 2D role-playing video game with a focus on story, player actions, and metafictional storytelling. Combat encounters in the game can be resolved through both lethal and nonlethal methods, with the game's dialogue, characters, and storyline changing depending upon how the player chooses to resolve encounters.

Upon Undertale's release, the game was well received by professional gaming publications and the general public, and gained a extremely large fandom on social media. The game's fandom became notable due to its size, activity, and variety of fan works, and has been covered by professional outlets. However, the fandom has also been the subject of controversy and negative reception due to the behavior of some fans.

In 2018 and 2021, Toby Fox released demos for a related game, Deltarune. Deltarune shares some story elements with Undertale, but varies in gameplay and story themes.

It inspired a pin ball version of the game.


In Undertale, the player assumes control of a human child who has fallen into the Underground, an underground region inhabited by monsters, who were sealed inside a mountain after losing a war with humans long ago. In searching for a way out, the child encounters different monsters, some friendly and some hostile.

During combat, the player can choose from various actions, including attacking, performing encounter-specific actions to pacify enemies, or offering enemies mercy. Enemy attacks play out similarly to a bullet hell game, requiring the player to dodge their attacks.

In-game character dialogue changes not only depending on in-game decisions, but from data management elements such as saving, loading, resetting, and multiple playthroughs. This aspect of the game, along with many hidden elements and easter eggs, encourages multiple playthroughs to find all of the game's secrets.


Major Undertale characters include:


Undertale's story changes and endings are sorted into three main "routes" by fans: Neutral, True Pacifist, and Genocide.[note 1]

  • Neutral: The default route, achieved by failing to meet the requirements for True Pacifist or Genocide. This route has different ending variations based on which major NPCs are alive at the end of the route and how high or low the main character's LV is.
  • True Pacifist: Achieved by never killing any monsters and completing the three hangout events.
  • Genocide (also known as No Mercy): Achieved by completing a kill count of monsters in each area and killing all bosses. Notably, the story is much darker in tone than the other routes, and completing the route permanently alters the ending of the True Pacifist and Genocide routes.

References to fandom

On several occasions, Undertale's updates and re-releases have incorporated references to the game's fandom.

  • The ship Nicepants (Burgerpants/Nice Cream Guy) is a crackship popularized by fic writers simplycarryon (also known as playeronecontroller), MiniNephthys, and others. The v1.01 update to the game gave Burgerpants some new dialogue implying that the Nice Cream Guy flirts with him.[citation needed]
  • The PlayStation port's trophies include references to Jewish mythology. This may be a reference to the fic writer Feral Phoenix, who writes the character of Chara as Jewish and uses Moses-related symbolism.[citation needed]




  • Asgore/Sans/Toriel (Sansgoriel)
  • Frisk/Chara/Asriel (Frischarasriel or Chariskriel)
  • Alphys/Undyne/Papyrus

Reader Insert Ships

  • Sans/Reader
  • Mettaton/Reader
  • Papyrus/Reader

Gen Relationships

  • Sans & Papyrus
  • Sans & Toriel
  • Papyrus & Undyne
  • Alphys & Sans

Undertale fandom is also prone to multishipping and rarepair fic and art.


Thanks to the innovative nature of the game, its high polish for a mostly single-developer project, and Toby's visibility as a creator involved with already popular works like Homestuck, Undertale's fandom took off almost immediately after the full game was released, and it exploded with a popularity that even Toby himself later referred to as overwhelming and intimidating.[1]

The new-fandom period of warm fuzzies and peace lasted for about a month or two, but then as with all large enthusiastic fandoms, pernicious wank and non-fan annoyance towards fans' exuberance began to emerge, and Undertale's fandom gained a reputation for being the latest Fandom That Ate Fandom. Despite this, it is still well-beloved for its story, gameplay, characters, and the highly personalized experience of playing it--even by many fans who are so frustrated by fandom drama that they refuse to interact with the fandom at large.

Undertale's popularity attracted the attention of many well-known indie and professional gamemakers worldwide, such as Hatoful Boyfriend creator Moa Hato, who loved the game so much that she created her own Let's Play of the neutral route with Japanese subtitles (now no longer available) in hopes of garnering fan interest in Japan. International interest led to the creation of fan translation patches in many different languages, and eventually to 8-4 releasing an official Japanese localization in 2017. Trends in ship popularity and fan interpretations sometimes differ from country to country.


Undertale has a myriad of "public-domain" AUs dabbled in by many fanwork producers. Some of them involve twists on the Undertale setting based on classic fic tropes, while others are more or less limited to aesthetic changes to the original setting rather than changing the plot. Several of both varieties originated as or take inspiration from fanart posted to tumblr. Many of these AUs are named a relevant noun prefaced by "Under-" or with "-tale" tacked on, stylistically similar to the naming scheme of Homestuck AUs that use "-stuck".

AU-centric fanworks commonly focus on characters from one AU meeting characters from another AU, or meeting themselves from another universe. The differences in these AU versions of characters can be as simple as a personality change, or so drastic that they could debatably be called original characters.[2]

Some parts of Undertale fandom, as well as people who aren't members of the fandom, find these kinds of AUs distasteful. Said detractors often believe them to be "cringey" or unnecessary. Proponents of Undertale's AUs would argue that this sort of fan content is only natural for a large fandom with many young fans, and draw comparisons to other game fandoms popular with kids and young teens like Five Nights at Freddy's. A commonly voiced opinion within the latter crowd is that older fans should calm down and let the kids have fun, no matter what they think of kids' fanwork.

Less infamous but still prevalent in fandom are AUs which place the characters in another fandom's setting and "for want of a nail" style fanfiction based on some change in the plot.

A whole wiki devoted to Undertale's AUs may be perused here.

  • Underfell - An "evil" AU where all the monster characters are portrayed as much more hostile than in canon. It became very popular and widespread.
  • Underswap - Roleswap AU where Frisk and Chara, Toriel and Asgore, Sans and Papyrus, Undyne and Alphys, and Mettaton and Napstablook switch roles. This has inspired other similar roleswap AUs, such as Storyshift.
  • Swapfell - An "evil" spinoff of Underswap in the same vein as Underfell.
    • Fellswap - An AU based on the same concept as Swapfell but with different designs. Set up as a Soviet Russia-inspired dystopia, based on the creator's real-life experiences in their home country.
  • Bitty Bones - Pet AU
  • Errortale - Glitch AU by CrayonQueen. The Sans from this AU is commonly known as Error.
  • Mafiatale - 20's-esque Mobster AU
  • Humantale - a Mundane AU
  • Dusttale
  • Dancetale - Think Undertale meets Happy Feet. An AU where monsters dance to communicate, and all major characters are associated with different dance styles.
  • Horrortale - AU in the style of indie horror puzzle/exploration games.
  • Outertale - Space AU
  • Reapertale - Mythology AU created by Renrink on tumblr, inspired by Greek and Christian mythology. Centered around Sans/Toriel. Information about the AU can be found here.
  • Floweypot (Houseplant Flowey) - A canon divergent AU where Flowey is brought to the Surface after the game, usually portrayed as living with Frisk and Toriel. Artists such as tumblr users velocesmells and creepyknees helped popularize this AU with comics.
  • Glitchtale - animation series by Camila Cuevas
  • Aftertale - webcomic by CrayonQueen
  • Christmas Party AU, CPAU for short - crossover AU by CrayonQueen
  • Handplates by zarla-s

Fan Characters

Aside from Reader Insert fanworks and creating AU spinoffs of canon characters, it is also highly popular within fandom to create OCs set in the Undertale universe. These fandom OCs range from original monsters--most popularly skeletons with font names or Boss Monsters, but also sometimes of other canon monster species or completely original monster characters--to human ones. Popular categories for human OCs include made-from-scratch characters created to populate the surface world in postcanon fanworks, as well as interpretations of the six human children who explored the underground and died pre-canon. Similarly, fans often create OCs based on the war-era human and monster characters in the game's opening stills. One such notable OC is Reada, created by tumblr user spottoydog (mod of the theory blog passivechara).

Interpretations of the six souls are often based on extrapolating headcanons from the flavor text descriptions of their equipment and of their soul traits revealed by the Ball Game minigame. Examples of such OCs include the cast of tumblr artist doreenchartreuse's Dreem Team AU fanart series, and recurring side characters in Feral Phoenix's you can only use your own series and other works.

Other notable fan OCs include Chisk, created by blending Frisk and Chara's sprites, and Linda, a bigoted PTA parent created to have enmity with Sans in the PTA Undertale tumblr AU. Linda in particular is a community OC whose portrayal varies depending on the fans drawing or writing her; she plays a large role in DoniDrabbles' longfic Blood of the Covenant.


As a game fandom, Undertale has resources for several media options for fans to be creative: text, art, video creation, Let's Plays and music are among the most common fanworks.

Not long after the full game was released, Toby Fox posted a request (in-character as Mettaton) that fans use the alternate tag "Undertail" for NSFW fanworks where possible, in order to help younger fans avoid accidentally stumbling across 18+ fanwork. The term Undertail was successively adopted for smut use, and is even used in overseas fandom websites, such as on Pixiv.

Initially, for-profit fan merchandise was forbidden by Toby for fear of other people profiting off the IP damaging sales to official merch and the like, but after consulting with a lawyer he released detailed guidelines for what sorts of for-profit fanmade goods are and are not allowed. Moa Hato keeps a Japanese translation of these guidelines available and updated for Japanese fans.

In Japanese fandom specifically, Undertale doujinshi and other fanmade goods such as acrylic charms are regularly sold at doujin events. In addition to making a strong showing at yearly events such as Kemoket (Comiket's furry fandom cousin) and pan-overseas game fandom events such as UNLIMITED EX, fans have organized multiple Undertale-only doujin events: Minna no Ketsui (Determination for All, abbreviated to MinKetsu) 1 and 2 in 2017, Yasashii Chitei Tanken (Explore the Gentle Underground, abbreviated to YasaChin or YasaTan) 1 and 2 in 2018, and Kimi no Sentaku. (Your Choice) 1 and 2 in 2019. Some doujin circles make limited runs of their products available to purchase via overseas-shipping-friendly vendors such as Alicebooks.

Fanfiction and Fanart

As of Apr 17, 2020 Undertale has 31,967 stories on Archive of Our Own and 9.6K on Fanfiction.net. Undertale inspires a surprising number of Reader Insert fics, and a lot of AUs, in both fic and art. Reader insert fics are encouraged by some fans as an alternative to using Frisk or Chara as a reader stand-in for writing romances with Sans (see "Shipping" under the Fandom Controversies section). Fanfics where the reader is not Frisk/Chara will frequently be tagged as "reader isn't Frisk" or "reader is not Frisk."

When sorting by relationship, Sans/Reader has 4,966 (15%) fanfics, Alphys/Undyne has 3,621 (11%), and Sans/Papyrus has 2,814 (9%) after that. 2,868 (9%) are tagged as Alternate Universe - Underfell (Undertale) and 1,915 (6%) as Alternate Universe - Underswap (Undertale). Sometimes, instead of tagging the fanfic it self as an AU, the author may simply tag the characters as being from a specific AU, such as "Sans (Underfell)." Like wise, when tagging canon characters it can be tagged as "Sans (Undertale)."

Fanfiction is usually post-game, set after the events of Undertale, or set at the beginning of the game. Notable exceptions to this rule are Not as Simple As a Happy Ending by Pastelclark, and You Can Only Use Your Own by Feralphoenix, both of which are set before the game begins.

Magicae est Potestas is a notable crossover, this one with the science fiction-fantasy series Artemis Fowl. Another notable crossover is A Cord of Two Strands, a crossover between Undertale and Outlast by author Ghostigos.

Video & Let's Plays

Let's plays are especially common, because many players don't want to play through all three main styles, and most players don't care to play through enough to find all the possibilities and easter eggs.

Fan Music

Undertale has been praised for its innovative original soundtrack, and the fans have run with it since the game's release.


Fan Games


Fan Comics


As Undertale's story features a number of plot threads that are mostly communicated through subtext or small plot hints, it is the subject of a great deal of fan theorizing. Popular subjects for speculation include the past of popular character Sans, the true identity of secret character W.D. Gaster and what relation he has to Sans and Papyrus, and what Chara's true role in the game and real moral nature are.

Most of these essays are full of spoilers and probably should not be read if you want to avoid being spoiled.


As Undertale was released in 2015, well into the era of fandom mostly living on Tumblr, there are fewer devoted hubs for fans to talk about Undertale than for fandoms of the 00s and earlier. However, a subforum for Undertale does exist on Toby's old hangout, the Earthbound fan forum Starmen.net. There is also a community devoted to datamining the game on Reddit, called Underminers.

Due to much of Undertale fandom history taking place on Tumblr, much of that history is currently at risk of being lost to Tumblr's 2018 NSFW purge. Preserving pages on the Internet Archive, backing up one's content to other websites, and encouraging others to do the same is strongly recommended.

Fandom controversies

Route Terminology

The route of the game that involves killing all monsters was nicknamed the "Genocide Route" in one of the first livestreams that featured it, wherein the player character was (as noted in the video description where it is posted on Youtube) "named Hitler in honor of killing everything". This sparked backlash from other groups, especially Jewish and Rromani fans, who felt the Holocaust joke to be in poor taste, and led to "No Mercy Route" being proposed as an alternate term. One Twitter user claimed that Toby Fox himself suggested "No Mercy" as an alternate term at a convention, but other fans doubt the truth of this story.

Arguments against the use of "No Mercy Route" involve that it is possible to never use the Mercy command without playing this route, as kill counts in each area must be exhausted to progress. Other terms such as the "Kill-All Route" are also used for this reason, and the different names for this route are sometimes used interchangeably in English-speaking fandom. "Genocide Route" or "G-Route" is the term most commonly used in Korean and Japanese fan communities, and AO3 tags that involve this route have been wrangled and rewrangled multiple times to change whether "Genocide Route" or "No Mercy Route" is considered the parent tag.

Route Culpability

The question of whether Frisk, Chara, or the player should bear blame for the Genocide/No Mercy route has been an increasing source of fan drama from 2016 onwards.

In 2015, when Chara was most commonly interpreted as pure evil and the game's villain, they were generally portrayed as being to blame for this route in fanworks and in meta; the theory being that Chara's "true goal" was to steal Frisk's soul via the Genocide/No Mercy ending, manipulate the player into playing True Pacifist afterwards, and therefore change places with Frisk and then wipe out humanity. This theory slowly began to fall out of favor as the narrator Chara theory rose in popularity in early '16, but this led to passionate fan wank as to whether the Genocide/No Mercy route is Frisk's fault or the player's.

Proponents of blaming Frisk for the worst ending, such as passionate theory blogger saveloadreset on tumblr, argue that the player should not be considered an in-game entity at all because that means that Frisk has no agency, and therefore makes their character arc "boring" or "meaningless". Fans who agree with this theory tend to produce fanwork where Frisk is portrayed as having a violent or angry nature, or portrays Chara as a victim forced to watch Frisk murdering the monsters. These fans also tend to accuse their opponents of bullying or gaslighting. An article on Kotaku bemoaning the "toxicity" of the Undertale fandom (ranging from documented problems such as inter-fandom harassment and bullying to more debatable "problems" such as the prevalence of ""bad"" ships and erotica featuring aged-up or postcanon versions of underage cast members; see Shipping below) conflated blaming the real-world player for the worst ending with the (sadly common) harassment of Youtube Let's Players who start the game with a Neutral route[3].

Proponents of blaming the player for the worst ending cite the metatextual nature of Undertale as a whole, and that many of Toby Fox's inspirations for the game, such as the Mother series, actively acknowledge the presence of the real-world player. Some of these theorists argue that Frisk's character arc is instead centered around identity and lack of agency[4] and that how interesting or meaningful individual fans find that is a matter of opinion. Others note that many fans who portray Frisk as violent ("edgy Frisk") and blame them for the worst ending portray Frisk as Black, which can have awkward implications when the producers of this sort of fanwork are not Black themselves.

Some fans on both sides of the argument criticize the way that fanwork treating the player as an in-game entity focuses disproportionately on Genocide/No Mercy players, which does not reflect how many real-life Undertale fans prefer to play the Pacifist and Neutral routes.

Shipping Discourse

The fandom is known for being largely involved in anti-shipping movements, groups of people who attack other fans over their shipping preferences. A lot of these reported cases center around Frisk, Chara, and Asriel. This is due to passionate fan disagreement as to whether or not it is appropriate to depict child characters in romantic relationships or feature them in 18+ works (even if aged up), complicated because fan interpretations of these characters' ages varies from very young children (5-6 years old) to early teens (12-13). There is also disagreement over whether or not shipping Frisk, Chara, and Asriel with each other counts as incest, as some fans interpret them as adopted siblings.

Fontcest is another controversial pair because of fandom's distaste for incest. Sans/Frisk and other ships where Frisk is paired with adult NPCs are controversial because of the age gap, again exacerbated by the difference in fans' personal headcanons as to how old each character is.

This inter-community conflict came to a head recently with the assault of Taiwanese fanartist Avimedes at a convention, when a fan gave her cookies with pins hidden inside them, causing lacerations in her mouth that required her to be hospitalized.[5] It is largely thought that the attack was instigated because of Avimedes' art of Frisk/Sans, however this has yet to be officially confirmed as the culprit hasn't been apprehended. Regardless, this event started trending far outside the Undertale fandom, and has since sparked conversation in and out of the fandom about the morality of these anti-ship movements.


This popular AU, a spinoff of Underfell that featured floral body horror, was subject to repeated incidences of art theft and unauthorized reposting to other websites, such as AO3. Some of the creators were subjected to harassment and threats, as well. After some time the project's original creator put the whole series on hiatus, and made the most plagiarized works in the series available only via her Patreon to try to avoid further art theft. Authorized translations of those works are only accessible via paywall as well.

The original creator of the AU has deleted all posts on the tumblr account she used at the time and has moved to a new account because of the harassment she experienced.

So Sorry

Not long after the game's initial release, fandom discovered the identity of backer character/cameo miniboss So Sorry's creator, Samael, and harassed them for having drawn fetish art unrelated to Undertale, which was deemed "inappropriate" and "disgusting". Theory blogger undertale-science encouraged the harassment campaign, painting Toby Fox as a victim forced to include a "fetishistic, sexual" character in his game because of the size of Samael's donation to the Kickstarter campaign. Other fans spread rumors that it was possible to kill So Sorry and still play the Pacifist run, creating fake screenshots of the judgment scene in which Sans says that the player didn't hurt anyone who mattered.

Toby Fox stated repeatedly to fans not to harass any backers and that all monsters are by nature good, but this did not stop the harassment campaign. Eventually Samael made a post on their own tumblr[6][7] about the harassment they were receiving, as well as the frustration they felt over So Sorry's reduced role in the final game and Toby's attempts at reproaching fans being unspecific and insufficient. Shortly after this, Toby made a much more specific post to his own tumblr[8] directly addressing the harassment of Samael. Both Toby and Samael stressed heavily that the situation between the two of them was "cool" and that they had come to an understanding on the matter.

After this incident, rumors began to spread about possible favoritism involved in how large a role Muffet, another backer miniboss, has in comparison to other backer-designed NPCs and So Sorry.

So Sorry has a slightly expanded role in the Switch version of Undertale: He can be met at any time on October 10, and if he has been met he will also appear near the entrance of Art Club in the postgame walkaround, even if it is no longer October 10 when the Pacifist route is completed. Toby also now makes announcements on Twitter when Art Club Day is approaching, so that players will have more of a chance to meet the character if they wish to.

Toby Impersonators

Throughout late 2016 and early 2017, various twitter and tumblr accounts claiming to be Toby Fox were made, often using photos of Toby from his high school years to try to lend credence to the hoax. These Toby impersonators often used said accounts to harass Undertale fans, whether for fun or because of an anti-shipping agenda. The impersonators eventually became such a problem that the real Toby had to make a statement about the trend on his real tumblr.[9]

Links & Further Reading


  1. ^ Neutral, True Pacifist, and Genocide are fan terms, as no official name is given for routes or endings.


  1. ^ Retrospective on UNDERTALE's Popularity - Toby Fox via the official Undertale tumblr, 14 September 2016 (retrieved 16 January 2019)
  2. ^ Can People Leave Sans Alone Please, Tumblr. Apr 20, 2020 (Accessed 4/23/2020)
  3. ^ The Undertale Drama, Chloe Spencer, 21 August 2017 (retrieved 12 December 2017)
  4. ^ AO3 comment by Feral Phoenix, 16 September 2017, retrieved 12 December 2017
  5. ^ A fan literally tried to murder a fanartist over... a ship?
  6. ^ Undertale - So Sorry, Archived version - samael on tumblr (accessed 10 October 2018)
  7. ^ Undertale - So Sorry Addendum, Archived version - samael on tumblr (accessed 10 October 2018)
  8. ^ About Sam / "So Sorry", Archived version - fwugradiation on tumblr (accessed 27 November 2017)
  9. ^ This is toby fox's tumblr. - fwugradiation on tumblr (posted 10 April, 2016); retrieved 14 April 2018