Sans

Sans is one of the major characters from the Undertale game.

Sans is the older brother of Papyrus. He first appears in the forest after the protagonist exits the Ruins. He serves as a supporting character in a Neutral and True Pacifist Route and as the final boss and heroic antagonist in a Genocide Route.

Appearance
Sans appears as a short skeleton with a dimpled smile, large eye sockets, and perfectly aligned teeth. He wears an unzipped blue hoodie, a white t-shirt/sweater, black shorts with white stripes, and a pair of sneakers/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.

Personality
Sans is laid back, 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."

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. He enjoys science fiction and loves to drink ketchup. He also hates making promises.

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

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

In combat, he uses "Gaster Blasters," 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. He also knows how much EXP the protagonist has and comments on it when judging them.

Sans also plays the trombone, though he is only seen playing it once. Papyrus 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.

Trivia

 * 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.
 * 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.
 * 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.


 * 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 or sentence starters, with a few exceptions. 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. However, in the official Japanese translation released in 2017, Papyrus refers to Sans as "niichan", 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.".