From Fanlore
Jump to navigation Jump to search
Name: Sans
Occupation: Sentry, illegal hot dog salesman
Relationships: In Undertale: Papyrus (brother), Toriel (friend)

In Deltarune: Papyrus (brother), Alphys (customer), Toriel (customer, one night stand (maybe))
Fandom: Undertale, Deltarune
Click here for related articles on Fanlore.

Sans is a major character from Undertale. He also has a minor appearance in Deltarune.

Canon Overview

In Undertale

Sans is the first character encountered in Snowdin. He initially appears as a black shadow stalking Frisk, appearing and disappearing behind the shadows of trees, but when finally catching up with them, he pranks them with a hidden whoopee cushion. He tells them that despite his position as a sentry, he has no interest in capturing humans, and sets them up to interact with his younger brother Papyrus, whom he claims is a "human-hunting maniac" but is also "harmless... even when he tries not to be". Sans then encounters Frisk throughout the area, making bad jokes and telling them how cool Papyrus is.

If the player spares Papyrus, Sans continues to appear throughout Frisk's journey for small joke events, and finally takes them out to dinner at the MTT hotel to explain that he would have killed them on sight if he had not made a promise to his friend Toriel to protect them. He is later encountered again in the Last Corridor of Asgore Dreemurr's castle, where he passes judgment on Frisk based on whether or not they have killed monsters. If Papyrus was killed, Sans is only encountered in the Last Corridor. Despite possessing a unique boss theme on the soundtrack, Sans is never fought in a Neutral route, and only briefly in a True Pacifist route as part of the Lost Souls sequence.

In a Genocide/No Mercy route, Sans recognizes the player as something inhuman, and continually threatens them throughout Snowdin when Papyrus is not present. He is the final boss of this route and has a reputation for being the most difficult boss in the game.

Like Flowey, Sans sometimes leans on the fourth wall, judging from Frisk's behavior whether they have played through a sequence of the game before.

In Deltarune

Sans may be encountered while exploring Hometown. He has apparently just moved to the town, and runs its grocery store, which looks curiously like Grillby's; he has apparently met Toriel and Alphys already but still knows few people. He spends his first conversation with Kris pranking and otherwise antagonizing them, but in the end asks them to come back tomorrow to hang out with Papyrus, who he says needs more friends.

If the player suggests that Sans should meet Toriel, Sans insinuates that he is having sex with her, which may or may not have been a joke but instantly became a meme between fans.


Sans is one of the most popular characters in the game, largely because of his behavior as last boss of the Genocide/No Mercy route, where he reveals that he has some knowledge of the story's meta mechanics. As a normally humorous character hiding that he is secretly powerful and has angst, Sans falls into many beloved angsty hero tropes, and his difficulty to fight led to his being characterized by fans as a secret badass. In the early stages of fandom, many fans expressed feelings of empowerment that the most beloved character in the game is a short and fat skeleton instead of a conventionally attractive character; later, fans began to express fatigue over the popularity of Sans-related content and to take issues with how fanon Sans' characterization differs from canon Sans.

Popular tropes in fanwork about Sans often center around his fearing the game being reset, his grieving for Papyrus or Frisk, or his having enmity with Chara. These tropes are sometimes criticized for coming too close to manpain.

Because W.D. Gaster's name also derives from fonts and due to hints in the game that they had something to do with one another, Sans is often characterized as having been related to or working with him in some way, and secretly being a skilled scientist. However, this is sometimes criticized by fans of Alphys, who feel that Sans is sometimes credited for her canonical accomplishments, much like female scientists struggle to be credited and appreciated for their brilliance in real life.

In fanworks, where Sans is in some way related to W.D. Gaster, it's also popular for Sans to understand Wingdings.

Domestic postcanon fan content where Sans and Frisk have a familial relationship often include Frisk calling Sans their "dunkle", a combination of "dad" and "uncle" and reference to the heavily-memed line "get dunked on" from Sans' boss fight. This originates from a comic by tumblr user creepyknees.[1]

Due to his popularity, Sans naturally stars in a great deal of NSFW stories and art; however this led fans to the dilemma of how exactly a skeleton ought to be depicted having sex. The most popular solution is for fans to make Sans able to conjure magical genitals (usually but not always a penis) that appear and function exactly like human genitals but glow blue, based on Sans' canon proficiency in blue magic. As a result, "Ecto-Genitalia (Undertale)" is wrangled as a common tag on AO3. This erotica trope is subject to a great deal of joking from fans, ranging in tone from fond to derogatory.

Sans' comments about Toriel in Deltarune led to "Sans Undertale fucked our mom" becoming a meme. Serendipitously the trailer for the live action and CGI Pokemon movie Detective Pikachu came out shortly after, causing the Pokemon fanbase to discover that the Pokemon Mr. Mime is canonically described as marrying the mothers of little boys in revenge if they don't like its tricks. This was rapidly combined with the Sans meme for jokes about mothers and the fucking thereof.

Sans' popularity made him a highly requested character to appear in Super Smash Brothers Ultimate, and on September 4 2019, a Sans costume to dress players' Mii characters up in was released as Smash Ultimate DLC.

On September 7 2022, Sans was the winner[2] of a poll run by the twitter account Tumblr Sexyman Of The Day to crown the Ultimate Tumblr Sexyman against poll opponent Reigen from the series Mob Psycho 100. Fans celebrated Sans' victory with the twitter hashtag #SANSSWEEP, and Toby Fox commemorated the occasion by writing fanfiction[3] about Sans and Reigen competing in this tournament.

Fan Theories

As mentioned above, Sans is widely theorized to be former Royal Scientist W.D. Gaster's son, brother, coworker, lover, experiment, or fragment. Some of these theorists assert or hope that Toby Fox will create a spinoff, sequel, or prequel to Undertale focusing on Sans' backstory and the connection, based on a tweet Toby made in 2016 about his next planned game being something "darker", and the phrase "dark yet darker" relating to W.D. Gaster in-game. Toby himself indicated multiple times that more Undertale content is unlikely ("Please erase all the dreams within your mind")[4] ("Undertale ended in a really good place with a lot of room for people to fill in the blanks with imagination. Do you really... want me to destroy that...?"). This turned out to be because he had something a little different planned.

Fans also debate whether Sans has any actual ability to recall the events of other timelines or not.

Fan speculation surrounding Sans is so passionate as to be overenthusiastic at times, with some of the wilder theories (Game Theory's "Sans is Ness" theory in particular) being likened to conspiracy theories, and mocked either lovingly or derisively by other fans. Even Toby Fox himself gently poked fun at Sans theorists' enthusiasm when the mockup screenshot he posted of the Undertale Alarm Clock app in its announcement, featuring Sans saying "fuck my dick"[5] with the expletives censored out,[6] sparked a flood of fan speculation about some possible deeper meaning.

Since the Deltarune demo was released, a new wave of theorizing about Sans' origins began; meta writers wonder if Sans and Papyrus originally came from Deltarune's world, or whether some other timespace shenanigans are going on that mean there's only one Sans and Papyrus in the whole multiverse, making the Deltarune skeleton brothers the ones we know from Undertale.

Common Pairings

Spinoff Characters

Because of Undertale's various popular AUs, different AU variations of Sans have become popular in fandom. In fanfiction where AU versions of characters meet, and especially in Sans/Sans fics, these spinoffs are referred to by different nicknames.

  • Underswap Sans: Often nicknamed "Blueberry" in meet-your-AU-self fics and roleplays. Has the same role as canon Papyrus, and usually has some changes to his characterization to match that role, ranging from being a more upbeat and less depressed version of canon Sans to having the exact same personality as canon Papyrus.
  • Underfell Sans (often nicknamed "Mustard")



Sans was the subject of drama in the Japanese fandom over how his speech should be rendered. Some fans felt that he should refer to himself with the first-person pronoun "boku" (僕) because of tweets that Toby Fox had made about his tentative ideas for how he might like characters to speak in Japanese. Others preferred for Sans to refer to himself as "ore" (俺), as the Japanese fan translation patch did. When 8-4's official Japanese localization was announced, fans expected it to settle the score between the two factions, but 8-4 chose for Sans to refer to himself as "oira" (オイラ) instead, leading to the formation of a third faction in the pronouns war. Some Japanese fans voiced suspicion that 8-4 had made this translation choice on their own without Toby's permission, but BNF Moa Hato (the creator of Hatoful Boyfriend) asked Toby directly and clarified that 8-4 had sought Toby's input before finalizing this localization choice. This whole incident was lovingly dubbed the "Oira Shock" by Japanese fandom.[7]

The 8-4 localization goes on to have Sans call himself "ore" in a handful of serious scenes, such as his boss battle in a Genocide/No Mercy route.


Especially because fan content featuring Sans is in itself so prevalent, Sans-related shipping drama runs high. Anti-shippers, some of them BNFs, target fans who ship Sans/Frisk and Sans/Chara because of the age gap, and fans who ship Sans/Papyrus due to it being an incest ship and therefore problematic. All of these ships are as a result significantly less popular in English-speaking fandom than they are overseas--Sans/Frisk especially is one of the most popular ships in East Asian fandoms. Sans/Toriel also has its detractors based on the age gap, but wank about it is less common because it is not an adult/child pairing; Sans/Toriel fans are, however, more likely to be involved with ship warring against rival ships featuring either character, particularly Asgore/Toriel.

Shipping Sans with AU versions of himself, which is especially common in roleplay communities, is often likened to Onceler fandom by the ship's detractors. Sans/Sans fans, however, felt validated because of a pair of tweets by the creator, where he said:

saw an undertale fanfic today with the description "Character/Pairing: Sans" and I've been thinking about how "Sans" is my favorite pairing

my OTP is just, sans, by himself

Toby Fox, @FwugRadiation on Twitter. Sep 20, 2015[8]

Even Sans/Reader, the most popular Undertale pairing on AO3, is not immune to ship wank--fans complain about its prevalence overall, as well as how much more common fics with female or DFAB reader inserts are than fics with male or DMAB ones.







Archives and Fannish Links


  1. ^ "this was absolutely necessary" - creepyknees, retrieved 19 January 2018
  3. ^ image post - Toby Fox via Twitter, posted 7 September 2022
  4. ^ Q: Will you ever announce a DLC for UNDERTALE, or a patch with a bunch of new content? A: Please erase all of the dreams within your mind. - Toby Fox on Twitter, posted 14 September 2016 (retrieved 23 November 2018)
  5. ^ (Posts a poorly drawn joke picture of Sans saying "f*** my d**k") (Immediate speculation at the deeper meaning) ...I respect your passion..., posted 15 September 2017, retrieved 11 February 2018
  6. ^ UNDERTALE 2nd Anniversary and ALARM CLOCK Development, posted 15 September 2017, retrieved 11 February 2018
  7. ^ Undertale's Japanese Localization Is Causing A Fan Frenzy, Brian Ashcraft. Posted 14 June 2017; retrieved 28 January 2018
  8. ^ Screencap of tweets on ifunny; original tweets have been removed from Twitter