|Date(s):||September 15, 2015 (English release); August 15, 2017 (Playstation/Japanese release); September 15-18, 2018 (Nintendo Switch release)|
|Country of Origin:||USA|
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Undertale is an indie-produced video game created by Toby Fox, who was well-known as a composer for Homestuck. It is a 2D pixel-art RPG with turn-based combat and a strong focus on the story. Unlike the vast majority of video game RPGs, Undertale's tag line is "The friendly RPG where nobody has to die.".
Within three months of release, Undertale had sold just short of 500,000 copies on Steam. It was ported to the PlayStation 4 and PlayStation Vita in 2017, also featuring a Japanese localization by 8-4. A Nintendo Switch port was released in 2018.
Gameplay and Setting
In Undertale's story, the player assumes control of a human child who has fallen down a hole and into the world of monsters, who were sealed inside a mountain after losing a war with humans long ago. In searching for a way out of the mountain, the child encounters several monsters of all sorts, some friendly and some hostile.
Combat is turn-based and front-view; on the player's turn, in addition to RPG standbys like attacking, fleeing, and using items, you can also choose to ACT (with a different set of available actions for each monster) to appease your opponent, or offer them Mercy. During the enemy's turn the player must dodge the enemy's attacks in the style of a bullet hell game. There is only one save file, and progress is saved both manually at save points and automatically to system data. The player automatically returns to the most recently passed checkpoint after dying, and can also quit and restart at their last save point or reset to the very beginning of the game at any time.
One of the most innovative aspects of Undertale is that several NPCs notice when you have reset--they will greet you differently when you reach a room for the second time, or if you kill or spare someone differently in your next playthrough. These meta aspects of the game and its many easter eggs have led some players to replay the game many times, trying to find all its secrets.
The three main "routes" through the game are based on three, mutually-incompatible play styles: Kill nothing, kill some things, and kill everything.
- Neutral: Played by killing one or more monsters. This route has many different ending variations based on which major NPCs are alive at the end of the route, and some flavor text changes based on how high or low the main character's LV is. After reaching the ending, the player is given the opportunity to replay the game from the beginning, and therefore play a different route if they choose.
- Pacifist: Played by never killing any monsters and befriending all bosses. At the end of the game the player will reach a special version of the neutral ending (sometimes called the Imperfect Pacifist Ending), and will then be given the opportunity to load their save file and continue the game with the ability to access new story events and areas, a unique boss, and the game's happiest ending (often called the True Pacifist Ending).
- Genocide/No Mercy: Played by satisfying a kill count of monsters in each area. There are two unique bosses in this route, and the story is much darker in tone than the other routes. Opportunities are provided by the game to revert to a neutral run partway through, and until the route is completed, the player is able to reset and replay a different route. Once this route is completed, the ending of another route is permanently altered as a consequence. This can only be reversed by cheating (altering or deleting the game's system saves).
There are many easter eggs present in the game, which helps ensure that every player has a unique experience. A non-comprehensive list includes:
- The "Fun" events, which are tied to a hidden variable in the game which generates a random value on each playthrough. These events include humorous extra phone calls, events tied to the game's resident cryptid W.D. Gaster (Alphys' predecessor as Royal Scientist) and his Gaster Followers, and viral previews for Deltarune. The Gaster events were accidentally dummied out of the very first release of the game, and became possible to access without cheating in version 1.01.
- The hidden bosses So Sorry and Glyde, both characters designed by backers.
- Events where Flowey can be spotted stalking the main character in certain areas if the player backtracks quickly.
- Some special events or dialogue are prepared for the player trying to behave in creative or unusual ways during certain parts of the story, such as dodging the friendliness pellets in Flowey's tutorial or dying in Toriel's boss fight (where the player normally cannot be killed) by using a healing item and then deliberately running into Toriel's bullets.
Provided in alphabetical instead of game-encounter order:
- Alphys, the Royal Scientist
- Asgore Dreemurr, the King of Monsters
- Asriel Dreemurr, the late Prince of Monsters
- Chara, a human
- Flowey, the flower
- Frisk, a human
- Papyrus, an excitable skeleton
- Mad Dummy, an angry mannequin
- Mettaton, a robotic TV star
- Monster Kid, a monster kid
- Muffet, a donut-selling spider
- Napstablook, a ghost DJ
- Sans, a lazy skeleton
- Toriel, a motherly goatlike monster
- Undyne, Captain of the Royal Guard
- Alphys/Undyne (Alphyne)
- Chara/Asriel (Charasriel or Chasriel)
- Frisk/Asriel (Friskriel)
- Chara/Frisk (Charisk or Frischara)
- Sans/Toriel (Soriel)
- Asgore/Toriel (Asgoriel)
- Mettaton/Papyrus (Papyton)
- Sans/Papyrus - Incest pairing known as Fontcest
- Sans/Frisk (Frans)
- Sans/Grillby (Sansby)
- Papyrus/Grillby (Papby)
- Sans/Gaster (Sanster)
- Undyne/Papyrus-Either as a BroTP or a case of friendship to love
- Sans/Sans - Undertale's many AUs make this a common pairing; AU Sans shippers often cite a tweet by Toby Fox saying that his favorite pairing is "Sans by himself" (in reference to the content descriptions of the second-ever Undertale fic posted) in support of Sans/Sans fic.
- Asgore/Sans/Toriel (Sansgoriel)
- Frisk/Chara/Asriel (Frischarasriel or Chariskriel)
Reader Insert Ships
- Sans & Papyrus
- Sans & Toriel
- Papyrus & Undyne
- Alphys & Sans
Fan References Within the Game
The game includes many puns and references to other fandoms.
- Flavor text describing an enemy called Loox claims its last name is Eyewalker, a reference to Star Wars
- Midboss Greater Dog's doghouse, which is very small, is described as "bigger on the inside" after fighting it, a reference to Doctor Who
- Examining a croissant on Muffet's bake sale table will cause it to be compared to a bracelet, a reference to The Legend of Zelda
Toby Fox cites EarthBound, Touhou, Shin Megami Tensei, Brandish, the Mario & Luigi RPGs, Cave Story, and Moon: Remix RPG Adventure as inspirations for different aspects of Undertale.
Similar to Homestuck (though to a much smaller degree), on rare occasions Undertale's updates have incorporated modest references to popular fanon.
For instance, the ship Nicepants (Burgerpants/Nice Cream Guy) was originally a crackship popularized by fic writers simplycarryon (playeronecontroller on tumblr), MiniNephthys, and a few others; the v1.01 update gave Burgerpants some new dialogue implying that the Nice Cream Guy flirts with him.
Similarly, the Playstation port's trophies include jokes based on Jewish mythology which might or might not be a nod to Chara-centric writer Feral Phoenix writing them as Jewish and frequently using Moses-related symbolism.
Toby's small nods to fandom trends continue in Deltarune, where some characters call Asriel by one of his popular fan nicknames in Undertale fandom, "Azzy", and there's even more Nicepants shiptease.
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.
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.
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.
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.
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
- 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
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.
These 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.
- jacksepticeye's playthrough's first episode
- ManlyBadassHero's Let's Play full playlist, including a few fan boss fights
Undertale has been praised for its innovative original soundtrack, and the fans have run with it since the game's release.
- Megalovania Extended Version Megalovania is Sans' boss fight music. One notable fan spin-off of this song is Megalomaniac a song about Sans' fight from both Frisk's and Sans' point of views.
- They Need A Monster is a song from Mettaton's point of view made by MandoPony.
- His Theme is the original song by bumble-lily from Asriel's and Flowey's point of view throughout the story.
- Undertale parody of Strong in the Real Way was made by dolce.
- Spider Dance Vocal Music Box Cover was created by adrisaurus. The lyrics go to the original tune.
- Promise Me is a song that was created by NateWantsToBattle from Toriel's point of view when Frisk first falls down into the Ruins. It is set in a Pacifist play through.
- Unaligned is a song that was created by NateWantsToBattle from Frisk's point of view during what is perceived to be the beginning when they are in the Ruins. It is set in a Neutral play through.
- An Ending was created by bumble-lily told from both Chara's and Frisk's point of view.
- Several Touhou-fandom-esque arrange albums have been spawned, including RichaadEB and Ace Waters' progressive-metal three-parter "Determination" and DM Dokuro's electronic/dance album "The Underground Radio" ( and its followup The Untouched Radio.)
- Underveil, a series of free tribute remix albums organized by the Japanese fandom and including tracks from some popular Vocaloid composers. The organizers hosted a live event in Ikebukuro on May 27, 2017.
- bad time memes by demondicecal
- Undertale Red - fan boss fight by taxiderby
- Undertale Yellow - fan prequel following the adventures of the yellow-souled human who fell into the Underground directly prior to Frisk
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.
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.
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.
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 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.
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. 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.
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 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 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.
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.
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.
- Why Would You Ever Climb A Mountain Like That? - Depression, Suicide, and Surviving in Undertale (about recurring motifs of mental health problems in the main story)
- Save (six essays, linked at the top of this post, about the significance of the Save sequences in the final battle of the True Pacifist Route)
- On Undertale And Fighting (an analysis of power dynamics in Undertale's discussion of pacifism)
- On Chara and RPG Morality (thematic analysis of Chara based on how Undertale examines popular RPG genre conventions)
- On Soul Virtues & the Undertale Main Cast / (Dreamwidth mirror) (thematic analysis of how the soul traits may line up with the major characters)
- HP. ATK. DEF. GOLD. EXP. LV. (theory of how the soul virtues may compare to stat parameters)
- Undertale & Violence Against a Child Protagonist (look at RPG child-protagonist conventions and the Mercy mechanic in response to a pearl-clutching anon)
- Undertale dares players to make a mistake they can never take back (discussion of the No Mercy route as commentary on completionist culture)
- Behind the Humor of Toby Fox's Undertale
- Why Undertale rules and why my co-workers are dummies for not including it in the Top 10 (editorial by Neutral-to-Pacifist-to-No-Mercy player Griffin McElroy on Undertale's morality system)
- UNDERTALE Release Trailer - YouTube
- Steam Sales Statistics Accessed Dec 15th 2015.
- Here are my thoughts on Ch 1 of Deltarune. This should answer some questions. - Toby Fox on Twitlonger, 2 November 2018 (retrieved 2 November 2018)
- Retrospective on UNDERTALE's Popularity - Toby Fox via the official Undertale tumblr, 14 September 2016 (retrieved 16 January 2019)
- Can People Leave Sans Alone Please, Tumblr. Apr 20, 2020 (Accessed 4/23/2020)
- The Undertale Drama, Chloe Spencer, 21 August 2017 (retrieved 12 December 2017)
- AO3 comment by Feral Phoenix, 16 September 2017, retrieved 12 December 2017
- A fan literally tried to murder a fanartist over... a ship?
- Undertale - So Sorry - samael on tumblr (accessed 10 October 2018)
- Undertale - So Sorry Addendum - samael on tumblr (accessed 10 October 2018)
- About Sam / "So Sorry" - fwugradiation on tumblr (accessed 27 November 2017)
- This is toby fox's tumblr. - fwugradiation on tumblr (posted 10 April, 2016); retrieved 14 April 2018