For the song named after this character, see sans..

i'm sans.
sans the skeleton.

Sans introducing himself.

Sans (/sænz/) is the brother of Papyrus and a major character in Undertale. He first appears in the forest after the protagonist exits the Ruins. He serves as a supporting character in the Neutral and True Pacifist routes and as the final boss and heroic antagonist in a Genocide Route.



Sans appears as a short, paunchy skeleton with a wide toothy grin, glove-like hands and large eye sockets. He wears an unzipped blue hoodie, a white shirt, black shorts with white lining, and a pair of salmon-colored slippers.[1] He has white pupils that disappear when he is serious or angered. When Sans uses telekinesis, his left eye flashes light blue and yellow, the colors for patience and justice, and his right pupil disappears.


Sans is laid back and flippant, often sleeping on the job and taking breaks. His laziness is a combination of fatalism and apathy. He wonders if his indolence stems from his knowledge that any progress he makes will be erased when the timeline resets. Conversely, he suggests that this knowledge could be "a poor excuse for being lazy."[2]

Though Sans is usually agreeable, he becomes eerily serious at particular moments. He is also observant; Sans reads the protagonist's expressions and can often tell when they have already done certain tasks. He enjoys making skeleton-related puns and the fact that he performs at MTT Resort hints that he may be a talented comedian.[3] He enjoys science fiction and loves to drink ketchup.[4] He also hates making promises.[5]

Sans may have a scientific background. Evidence includes the quantum physics book, workshop, his relationship to Alphys,[6] affinity for science,[4] and his timeline research.[7]


Sans can quickly travel or teleport using what he calls "shortcuts."


A "Gaster Blaster" that Sans uses in battle.

In combat, he uses "Gaster Blasters,"[8] devices that resemble a skull, to shoot large beams. Sans excels in combat and fights with unique abilities that include: KR, applying directional forces directly upon the protagonist's SOUL, and attacking the protagonist in their own selection menus.

Because of his "research," he has knowledge of timelines and the SAVE function. However, he does not retain his memories when the protagonist loads a SAVE, and he cannot use the SAVE function. His awareness of time travel makes him scrupulous, and he recognizes when the protagonist is behaving unusually. Sans reads the protagonist's expression and determines if they have experienced events before and are repeating them.[9] He also knows how much EXP the protagonist has and comments on it when judging them.


Sans playing a trombone

Sans also plays the trombone, though he is only seen playing it once while the protagonist is dating Papyrus. Papyrus also finds his "incidental music" annoying, implying that he has played many times before.

Like other characters, Sans is aware of when the game's code suffers bugs and calls the protagonist a "dirty hacker" if they achieve an impossible ending of a Neutral Route.[10]

Main Story

Neutral Route


Sans's first appearance in Snowdin Forest.

Sans introduces himself to the protagonist in Snowdin Forest after he initially appears as a silhouette. He explains that he has no interest in capturing humans, but that his brother, Papyrus, does.[11] Then, Sans hides the protagonist behind a lamp whose shape is identical to the protagonist's. Papyrus rushes onscreen, and the brothers discuss Sans's laziness and the importance of puzzle upkeep.[12] Sans appears multiple times throughout Snowdin Forest, observing and commentating on the puzzles but not engaging in any japery, except for the word search.

Before Papyrus's battle, Sans is absent in Snowdin Town. He appears briefly to play trombone during the date/hangout with Papyrus but does not appear again until the Last Corridor if the protagonist kills Papyrus.


A spotlight falls on the protagonist and Sans as "Premonition" plays.

After entering Waterfall, Sans is found manning a sentry station and asks the protagonist if they want to take a break with him. If the protagonist agrees, he takes them to Grillby's via a "shortcut." The patrons warmly greet Sans, and he proceeds to treat the protagonist to a burger or fries. After some dialogue, a spotlight falls on him and the protagonist and time appears to stop as Sans tells the protagonist that a flower has been talking to Papyrus.[13] Sans believes that someone is tricking Papyrus with an Echo Flower when the flower in question is Flowey.[14] Sans can be seen again in Waterfall and pranks the protagonist with a red-eye telescope. Later, if Papyrus was killed, then "a hooded figure" watches Shyren's battle. However, if Papyrus was spared, then Sans sells concert tickets made of toilet paper, implying the other figure was Sans as well.

Head dogs

The protagonist passes him sleeping at a sentry post in Hotland when fleeing from Undyne. Undyne notices him sleeping and berates him mid-chase.

Later, Sans sells Hot Dogs in Hotland for 30G. If the protagonist attempts to buy a hot dog when their inventory is full, he stacks a maximum of 30 hot dogs on their head for free.[15]


Sans and the protagonist at MTT Hotel's restaurant as "It's Raining Somewhere Else" plays.

Further on, Sans waits outside of MTT Resort and asks the protagonist if they want to grab a bite to eat. He escorts the protagonist inside via "shortcut" and talks about a woman he has befriended that shares his affinity for puns.[16] He tells the protagonist that this woman made him promise to protect any human that left the Ruins and that, if she had not said anything, the protagonist would be "dead where [they] stand." He dismisses this as a joke immediately and says that he has done a great job protecting the protagonist. If the protagonist has not died before, Sans takes credit for their success. If the protagonist has died, Sans questions the validity of his statement.[17] Before leaving, he tells the protagonist to take care of themself because someone really cares about them.


The end of your journey is at hand.
In a few moments, you will meet the king.
You will determine the future of this world.

Sans's introduction in the Last Corridor.

The protagonist encounters Sans for the last time in the Last Corridor. He explains that EXP and LOVE are acronyms - "EXecution Points" and "Level Of ViolencE"[18] and judges the protagonist for their current EXP.[19]

If the protagonist gained no EXP, Sans skips his judgment, instead praising the protagonist for embracing compassion and actively choosing to be merciful to the monsters throughout their journey. He reinforces the idea that the protagonist's actions shall decide the fate of the world in one of two ways: the protagonist lets Asgore take their SOUL and allow the monsters to break the Barrier or they take Asgore's SOUL to escape the Barrier themselves.[20] Sans concludes that the protagonist now has enough determination and believes that they can do the right thing before leaving.[21]


Sans's workshop entrance is located behind his house.

If the protagonist has heard his speech before, Sans notices their bored expression and offers a secret codeword that he uses to prove that they are a time traveler.[22] After the protagonist loads their SAVE a few times, Sans's suspicions are affirmed and he gives them a key to his room.[23] Inside Sans's room is a key to his workshop.

If the protagonist gained EXP, Sans allows them a moment to think about their actions. He then emphasizes the importance of integrity and, if Papyrus is alive, concludes that whatever happens next is up to the protagonist.[24] If the protagonist killed Papyrus, Sans expresses his suspicion that they have some special power. He then asks if the protagonist thinks it is their responsibility to do the right thing.[25] Regardless of their answer, Sans reminds the protagonist of his fallen brother and leaves.

If the protagonist returns to the Last Corridor after loading a SAVE, Sans judges the protagonist on their earned LV. Subsequent attempts to talk to Sans after judgment prompts him to tell the protagonist to "consider [their] session over."

Sans's LV Judgment

Sans's judgment occurs after he re-explains LOVE and EXP, and after he tells the protagonist to look inside themselves.
(Before Judgment)
  • huh?
  • you look bored.
  • i get the feeling you aren't gonna learn anything from this.
  • well, guess i gotta judge you then.
(LV 1, but more than 0 EXP)
  • ... huh?
  • what's with that look in your eye?
  • did you go through and kill someone...
  • just to see what i'd say about it?
  • wow.
  • you're a pretty gross person, huh?
(LV 2)
  • lv2...
  • seems like you messed up the slightest amount.
  • welp.
  • that's pretty sad.
  • you probably weren't even aware of what you were doing...
  • and when you learned, it was too late.
  • nah, just kidding.
  • who gets to lv2 on accident?
  • get outta here.
(LV 3)
  • lv3...
  • 3's just an ok number, i guess.
  • i'll give you a C+.
  • you can do better, right?
(LV 4 – LV 9)
  • hmmm...
  • over lv3, huh.
  • you killed some people on purpose, didn't you?
  • that's probably bad.
  • though, maybe some of it was in self-defense...
  • i don't know.
  • help me out here.
  • i wasn't watching.
  • anyways, don't do that.
(LV 10 – LV 14)
  • hmmm...
  • over lv9, huh.
  • that's over halfway to lv20, the maximum.
  • but don't think that means you're still 50-percent good.
  • 50-percent, 20-percent.
  • those are both still failing grades.
  • besides.
  • chances are...
  • i've already tried to steer you in the right direction.
  • so what can i say?
  • what can i say that will change the mind of a being like you?
(LV 15 and Above)
  • hmmm...
  • over lv14, huh.
  • well, hmmm...
  • judgment-wise...
  • you're a pretty bad person.
  • you wander around, looking for people...
  • killing them to take their money.
  • that's just plain messed up.
  • and what's worse, is that as bad as you are...
  • you aren't anywhere near as bad as you could be.
  • you pretty much suck at being evil.
  • honestly, it's super embarrassing.
  • but maybe you'd be better...
  • at not killing anyone?
  • crazy idea, huh?
  • let me know how that one goes.



After the protagonist defeats Photoshop Flowey, Sans calls and informs them of the events that transpired after their departure. The content of this phone call varies depending on the protagonist's actions; a list of the endings that Sans describes is on the Neutral Route page.

True Pacifist Route

Friends Captured Curse you Flowey

Sans is absent from the Last Corridor in a True Pacifist Route. There is also no SAVE point upon entering the corridor. He appears during the pre-Asriel cutscene and meets Toriel face-to-face for the first time. Flowey binds Sans and the protagonist's other friends. However, the protagonist's friends protect them from Flowey's attacks before Flowey absorbs their SOULs.

During the battle against Asriel, Sans appears as one of the Lost Souls.



After defeating Asriel, Sans stands alongside the other main characters. If the protagonist talks to him, he says a certain remark depending on what, if anything, the protagonist said to Toriel in calls at the beginning of the game.[26] Sans also uses Toriel's phone to text for her a few times because Toriel's thumbs are too big for the phone buttons. When the protagonist is ready to leave, Sans exits the Underground and heads to the Surface along with the other monsters.

When Papyrus runs off to introduce himself to the humans, Sans says that someone must keep him away from trouble and runs off in the opposite direction, presumably to use a "shortcut."


In the credits, Sans rides a tricycle on a highway, while his brother races alongside him in a car. Papyrus seems irritated when his brother overtakes him.

Genocide Route

if you keep going the way you are now...
you're gonna have a bad time.

Sans's warning to the protagonist in a Genocide Route


Sans disappears in front of the protagonist.

Sans stalks and introduces himself to the protagonist as usual but requests that they continue pretending to be a human.[27] He does not comment on the protagonist turning around before he asks them to. Sans goes along with Papyrus's japery and does not appear as an NPC as he does on other routes. After the protagonist crosses the bridge before Snowdin Town, Sans warns them not to fight his brother or else they will "have a bad time." He then disappears and is absent until the Last Corridor.

If the protagonist aborts a Genocide Route by sparing Papyrus, Sans reappears at the Waterfall sentry station and tells the protagonist he respects them for doing that.[28] He continues to appear as if on a Neutral Route but does not take the protagonist to Grillby's since there is no one left in Snowdin. Alternatively, Sans follows the protagonist if they kill Papyrus.[29]


Sans's Last Corridor speech in the Genocide Route.

The protagonist encounters Sans in the Last Corridor for his battle.

For further information, see Sans/In Battle.
After defeating Sans, the protagonist's EXP is set to 99999, granting them LV 20. Sans notices if the protagonist has killed him before and is re-fighting him.[30]

Sans does not count as a kill in the Stats menu, and the game does not record whether or not he is killed.

In Battle

For an in-battle description, see Sans/In Battle.


The Protagonist

take care of yourself, kid.
'cause someone really cares about you.

Sans after his rendezvous at MTT Resort

Sans's attitude towards the protagonist depends on their actions, though he usually enjoys pranking them and occasionally hanging out with them unless they kill Papyrus. Near the end of a Neutral or Genocide Route, he judges them on their EXP. At the end of the True Pacifist Route, Sans considers them a good friend. If the protagonist killed Papyrus, Sans does not bother to encounter them until he judges them in the Last Corridor, where he reminds them that they killed his brother.

Sans initially considers the protagonist to be an "anomaly"; his intentions of befriending them were in hopes that they would stop resetting the timeline.[31] However, he also says that the protagonist did not die after their initial encounter because of his promise to Toriel. This may imply he would have killed the protagonist, he protected them from life-threatening harm after their first encounter, or he was simply joking.


You dirty brother killer.

Sans during his judgment when Papyrus is killed

Sans cares for and admires his brother. He keeps up with Papyrus' temper tantrums and he knows how to deal with Papyrus' childish outbursts. Sans also reads him bedtime stories[32] and gives him presents under the identity of Santa.[33] Nonetheless, Sans likes to mess with Papyrus, sending him bad puns on the UnderNet.[34] He also leaves a dirty sock in their living room for Papyrus to fuss over.

Sans worries about others hurting Papyrus or taking advantage of him. In the Papyrus Ending of the Neutral Route, Sans is afraid to tell Papyrus about other characters' deaths, so he lies about them going on a vacation.[35]


Toriel and Sans share a love of bad jokes and are friends even though they never see each other face-to-face until the epilogue, the Family Ending, or the Exiled Queen Ending. Before the protagonist's arrival, Sans and Toriel shared jokes through the door to the Ruins.

In the Exiled Queen Ending, Sans becomes Toriel's roommate if Papyrus has been killed. In this route, Sans also states that he "can't bear to tell her what [the protagonist] did." If Papyrus is alive, the brothers visit Toriel often, play board games together, and sometimes convince Toriel to leave the Ruins.

While not being one to make promises, Sans complies with Toriel's request to watch over and protect any human that exits the Ruins. Near the end of the Genocide Route, he indirectly apologizes to her, as he is forced to break his promise to stop the protagonist.[36]


Though there is evidence that Sans and Alphys have a relationship,[37] Sans only alludes to this in the epilogue.[6]

It is also noteworthy that if Papyrus is called just before entering the Laboratory, Sans appears in the call and state that there may be dogs inside the lab.[38] This hints that he knows about the true lab since Endogeny, an Amalgamate composed of several dogs, can be found there. According to Alphys in an aborted Genocide Route, she is forced to rule the underground and Sans helps her lead; she calls Sans "a good guy".

W. D. Gaster

A few things hint at a connection between Sans and W. D. Gaster. Evidence includes the blueprints and veiled machine found in his workshop, the sprites used for his skull-like laser guns (labeled gasterblaster in the game files), and his unexplained scientific research on the "anomaly" and timelines. Sans and Papyrus are named after a font, which W.D Gaster is assumed to also be, so it is believed they are related.



  • Sans's name alludes to the typefaces in which he speaks in: Comic Sans and Sans Serif. This is a reference to Helvetica, a webcomic about a skeleton named after a font.
    • In Japanese phonetics, Sans's name is homophonous with the name of the Sanzu River, a boundary between death and the afterlife in Buddhist lore which, like Sans, judges all who cross it for their deeds. The Sanzu River is also a recurring locale in the Touhou series, from which Toby drew inspiration for Undertale's bullet hell battles.
  • Sans is a Mii costume for the Mii Gunner in Super Smash Bros. Ultimate. The Gaster Blaster is used as the Mii Gunner's arm cannon. The Sans Mii Costume and MEGALOVANIA remix can be bought for $0.75.
    • Sans is the first Mii Costume in Super Smash Bros. Ultimate to include a song with it.
  • If the player attempts to name the fallen human "Sans," the game responds with "nope." and prevents the name from being used.
  • He makes an appearance alongside Papyrus at the end of the Undertale Demo if the protagonist gained no EXP.
  • Sans appears to be left-handed. Evidence includes:
    • Greeting the protagonist with a handshake using his left hand.
    • Holding and drinking a ketchup bottle with his left hand while dining at Grillby's.
    • Steering a tricycle using his left hand in the True Pacifist Credits.
    • Manipulating gravity with his left hand in his battle.
  • When the "fun" value is between 45 and 50, Sans calls the protagonist in Snowdin Forest to ask if their fridge is running.[39]
  • There is a glitch in which Sans walks up off the screen at Grillby's when he takes the protagonist there. His dialogue still appears normally.[40]


  • There are two unused overworld sprites of Sans in the game files, one showing him with his pupils (spr_sans_dangerous_0) and one showing him holding an ice cream.
  • Sans speaks in all lower case, not even capitalizing names[41] or sentence starters, with a few exceptions.[42] This may be a representation of how lazy he is.
  • In a deleted tweet, Toby Fox said that Papyrus would use the term "Aniki," a Japanese honorable term used for older brothers or superiors. There are a multitude of interpretations for this as it doesn't give a clear answer.[43] However, in the official Japanese translation released in 2017, Papyrus refers to Sans as "Nii-chan", a somewhat immature way of addressing one's older brother.
  • Sans's line "on days like these, kids like you... Should be burning in hell." could possibly be a reference to a line said by Captain Strong in EarthBound, which goes "At times like this, kids like you should be playing Nintendo games."
    • In addition, the first part of this quote is a direct reference to a quote of Asgore's on a Neutral Route.[44]
  • In the 5th Anniversary Alarm Clock text, Undyne was talking about a hockey game everyone had played against her. Once Sans scored a goal, he went over to Alphys and did a "finger-pointy arm-crossy dance," implied to be the Fortnite emote Dance Moves, more commonly known as the Default Dance.

See also


  1. His Steam card shows him wearing sneakers and official merchandise shows him wearing slippers.
  2. "you can't understand how this feels. knowing that one day, without any warning... it's all going to be reset. look. i gave up trying to go back a long time ago. and getting to the surface doesn't really appeal anymore, either. 'cause even if we do... we'll just end up right back here, without any memory of it, right? to be blunt... it makes it kind of hard to give it my all. ... or is that just a poor excuse for being lazy...? hell if i know." – Sans
  3. "(It's a performance schedule.) (Comedians, dancers, Sans...)" – flavor text in the restaurant at MTT Resort.
  5. "i asked her what was up. then she told me something strange. 'if a human ever comes through this door... ...could you please, please promise something? watch over them, and protect them, will you not? now, i hate making promises. and this woman, i don't even know her name. but... someone who sincerely likes bad jokes... has an integrity you can't say 'no' to." – Sans
  6. 6.0 6.1 "WAIT, ALPHYS, I DIDN'T KNOW YOU KNEW SANS." – Papyrus, True Pacifist Ending.
  7. "our reports showed a massive anomaly in the timespace continuum." – Sans
  8. The names of the sprites used for his attack animations begin with spr_gasterblaster_.
  9. "that look on your face while i was talking... you've already heard my spiel, haven't you? i suspected something like this. you're always acting like you know what's going to happen." – Sans
  10. "i'll be honest. i have no idea what happened for you to get here. this is actually some sort of error-handling message. so, if you're getting this ending... tell whoever made the game, okay? chances are, though... you're just a dirty hacker, aren't you? yeah, get outta here." – Sans's message to the protagonist if an impossible Neutral Route ending is achieved.
  11. "i'm actually supposed to be on watch for humans right now. but... y'know... i don't really care about capturing anybody. now my brother, papyrus... he's a human-hunting FANATIC." – Sans
  13. "have you ever heard of a talking flower? ... so you know all about it. the echo flower. ... what about it? well, papyrus told me something interesting the other day. sometimes, when no one else is around, a flower appears and whispers things to him. flattery... advice... encouragement... ...predictions. weird, huh?" – Sans
  14. "FLOWERS...? DO ANY OF THEM TALK!? SAY HI FOR ME!!! FLOWERS ARE OUR BEST FRIENDS!!" – Papyrus, if the protagonist calls by the yellow flowers in the Garbage Dump.
  15. "i'll be 'frank' with you. as much as i like putting hot dogs on your head... thirty is just an excessive number. twenty-nine, now that's fine, but thirty... does it look like my arms can reach that high?" – Sans
  16. "so i keep 'em coming, and she keeps laughing. she's the best audience i've ever had. ... we kept telling each other jokes for hours. eventually, i had to leave. ... but she told me to come by again, and so i did. then i did again. and again. it's a thing now. telling bad jokes through the door. it rules." – Sans
  17. "haven't i done a great job protecting you? i mean, look at yourself. you haven't died a single time. hey, what's that look supposed to mean? am i wrong...?" – Sans
  18. "What's EXP? It's an acronym. It stands for 'execution points.' A way of quantifying the pain you have inflicted on others. When you kill someone, your EXP increases. When you have enough EXP, your LOVE increases. LOVE, too, is an acronym. It stands for 'Level of Violence.' A way of measuring someone's capacity to hurt. The more you kill, the easier it becomes to distance yourself. The more you distance yourself, the less you will hurt. The more easily you can bring yourself to hurt others." – Sans
  19. "You will be judged for every action. You will be judged for every EXP you earned." – Sans
  20. "your actions here... will determine the fate of the entire world. if you refuse to fight... asgore will take your soul and destroy humanity. but if you kill asgore and go home... monsters will remain trapped underground. what will you do?" – Sans
  21. "but you didn't get this far by giving up, did you? that's right. you have something called 'determination.' so as long as you hold on... so long as you do what's in your heart... i believe you can do the right thing." – Sans
  22. "so... i have a request for you. i kind of have a secret codeword that only i know. so if someone tells it to me... they'll have to be a time traveler. crazy, right?" – Sans
  23. "so, i guess you're qualified. here's the key to my room. it's time... you learned the truth." – Sans
  24. "truthfully, it doesn't really matter what you said. all that's important is that you were honest with yourself." – Sans
  25. "you act like you know what's gonna happen. like you've already experienced it all before. this is an odd thing to say, but... if you have some sort of special power... isn't it your responsibility to do the right thing?" – Sans
  26. Toriel:"Sans, did I tell you about the time Frisk flirted with me...? And then asked to call me 'mother?'"
    Sans:"oh boy." – Sans and Toriel in the epilogue.
  27. "well, i'll be straight-forward with you. my brother'd really like to see a human... so, y'know, it'd really help me out... if you kept pretending to be one." – Sans
  28. "hey, i really respect what you did back there." – Sans
  29. "A hooded figure watches the commotion from afar." – Flavor text from Shyren fight.
  30. "that expression that you're wearing... well, i won't grace it with a description." – Sans
  31. "sounds strange, but before all this i was secretly hoping we could be friends. i always thought the anomaly was doing this cause they were unhappy. and when they got what they wanted, they would stop all this. and maybe all they needed was... i dunno. some good food, some bad laughs, some nice friends." – Sans
  32. "eventually, i had to leave. papyrus gets kind of cranky without his bedtime story." - Sans
  33. "That's strange. There was a present here for Papyrus. Now it's gone. Did someone steal it?" - Gift Bear when Papyrus is killed
  36. "welp. sorry, old lady. this is why i never make promises." – Sans
  37. "WAIT... THAT BAG OF DOG FOOD LOOKS FAMILIAR. I REMEMBER SEEING IT... IN SANS'S ROOM?" – Papyrus, on the bag of dog food in Alphys's lab.
    Sans: "the sign outside says "lab.""
    Papyrus: "LAB?"
    Sans: "like... laboratory."
    Sans: "i mean. i wouldn't rule it out."
    - Phone call in Laboratory Entrance
  39. "hey. is your refrigerator running?" - Sans
  41. "now my brother, papyrus..." - Sans
  42. "he's a human-hunting FANATIC." – Sans
  43. "papyrus would definitely use "aniki." i think. what's your take." – Toby Fox. September 10, 2015. Twitter
  44. Nice day today, huh? Birds are singing, flowers are blooming... Perfect weather for a game of catch. - Asgore

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