Undertale AU Wiki
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This article contains information that is from an AU with multiple stories that has at least one story completed.

Stories that have been completed:
Xénotale: Celerity
Xéno!Papyrus's journey
Xéno!Frisk's arrival

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"Down here, hope is useless."
– Frisk to the armored guard

Xénotale is an Undertale AU created by Zeno Dreemurr on September 22, 2018 that shows the fear that monsters can have or give as well as any action has consequences. The AU is mainly shared by scriptural stories. Some Undertale events are rewritten by the creator, though the story is close to the Undertale one. It is an AU that also partially rewrites some aspects of the lore of Undertale, and adds its own lore, characters and locations into it.


Undertale Characters


Main article: Frisk

Frisk is the 8th human to fall into the Underground. As soon as she fell, she began to hear a voice. She lost consciousness and wanted to scare all the monsters, and when she gets tired of scaring them or cannot, she kills them. In the pacifist route, she is controlled by Chara, and in a eidocide route, she wants to kill everybody to punish Chara, who controlled her in the pacifist route.

She is very arrogant and seem to always has been, and hates disobedience, often screaming at Chara or The Voice if they don't obey her, mostly asking them to don't talk or, to The Voice, to give her the solutions to the puzzles. However, she can also like people, as her love for Papyrus grows during her journey into Snowdin. She also is patient enough to fish until she gets something, and kind to vendors. She doesn't hide how much she likes Papyrus, and is frank when she speaks. Due to her new ability, she loves to use it and complains if she can't use it or if she hasn't used it for hours only, killing people in the first case. She tends to underestimate monsters, but recognizes when they are strong. She can be interested in stories that happen in the Underground. She accepts advice when people argues about them and follows them sometimes. She doesn't care about how the monsters fell, and mocks human and monsters for various reasons.

She looks like Classic!Frisk but she has no shorts. Her eyes are red with red outlines around them and are open. Her eidocide appearance is slightly different because she uses a bloody true axe.

In the current published material, Frisk fells in the Underground and meets Chara and The Voice. She traverses the Underground with them and plays a game where she scares monsters or kills them if she's unable to do so. She traverses the ruins, where she meets Toriel and kills her to escape it. She also goes through Snowdin, where Papyrus rules and eventually survives to his traps, kills the armored guard and becomes a great friend of Papyrus's. She also goes through Waterfall, where she kills Undyne, the captain of the royal guard. The difficult part for her is where she is in Hotland and dies to Alphys's trap multiple times, even if she has Gaster as an ally. Fearing the CORE, Gaster forces Frisk to fight Aster and she survives to the fight, going to the CORE. There, she falls in the oblivion prison but escapes and kills Mettaton. She ends up in New Home where she fights Asgore and Flowey to end up getting back the surface.. Her first appearance is in the first episode.

In Xéno!Papyrus's journey, she is killed by Papyrus while doing her eidocide. Not long after her death, she finds herself in the loading screen to continue and kill Papyrus. Though, Papyrus comes and the possibilities disappear. There, she fights Papyrus again and dies again.

She is the protagonist of Xéno!Frisk's arrival as well, in which she discovers the Multiverse after a neutral ending. In this story, she joins Zeno's organization in exchange of being freed from Chara. She then does missions under Zeno's orders with helps from The Voice and from Error404's minions.


Main article: Chara

Chara is the first human to fall into the Underground. She also had the determination and heard The Voice. Because of this, Asgore killed her several times but one day, she died without being able to use her determination to resurrect. Her soul was then destroyed by Asriel. Later, when Frisk fell, she resurrected in Frisk's mind with a ghost of her soul. In the pacifist route, she controls Frisk and make her do the pacifist route. In the eidocide route, she sacrifices herself -even if it's pointless- to try to keep Flowey alive. She knows and hates that The Voice made Frisk lost her mind.

Before she heard The Voice, she was jovial and happy with her family, but after she heard it for the first time, she became a bit crazy and scared of Asgore back then, she liked to go in the wishing room with Asriel. When she resurrected inside Frisk's mind, she began to have bad memories and, because of seeing Frisk half manipulated by The Voice, started to hate Frisk and be afraid of her. She also seems to enjoy the times Frisk dies and hates the scare act. Like Frisk, she wants to know how to solve the puzzles. Upon seeing lovers, she shows herself caring a lot about them and finds them cute. She dislikes narcissism, and since only Frisk and The Voice can hear her, she doesn't hesitate to tell them what she thinks. She sometimes congratulate Frisk for what she does, or even agree with her rarely.

She looks like Classic!Chara, but because of Asgore attacks in the past, she has scars everywhere on her body. At the end of the eidocide route, she has been gashed.

In the current published material, Chara meets Frisk and The Voice when the former fell. Though she is mostly a voice in his head, she is also a secondary character of a point of view, which describes what happens to Frisk when she can't, or when she has some private discussions with The Voice. During the story, she mainly criticizes Frisk for her actions, but learns the story of the Underground since her death, which is told during episode 49. When Frisk gets back to the surface, The Voice said she would be with Frisk forever. Her first appearance is in the first episode.

She has a minor role in Xéno!Frisk's arrival, in which she is freed from Frisk's body and gets her own body back, only for Frisk to bring her in her bedroom. In the end, Zeno frees Chara from Frisk's bedroom and brings her in the Void of the specific timeline she is in, where she gets her own house.


Main article: Flowey

One day, Alphys did experiments on the determination on the last golden flower of the Underground. Asgore thought injecting too much determination into this flower would make it melt like monsters. Instead, Flowey was born with the power of determination, but he heard The Voice and began to be afraid of them. He squatted at Alphys's lab in secret, but she found and turned him later. He sought asylum several times but in vain, so he tried to kill her, but she survived. He ended up being his main test subject, but during an experiment, everything went wrong. It turned out that humans too could only contain a limited amount of determination and Flowey absorbed more than that amount. He recovered his power to manipulate the save file but some of his parts melted anyway. He met Frisk soon after and lost his power again. He started to be afraid of her and then disappeared. During the neutral route, he spies Frisk, but after her fight against Asgore, he fights her, the fight having five phases. During the eidocide route, he's the last one killed by Frisk.

He's a flower who hates the power of the determination and The Voice. He is also afraid of them, Alphys and Frisk. He's nice with everybody except very rare times when he's naughty. He doesn't hesitate to fight if it's necessary and, so, fight Frisk in his normal form in the first phase of his fight.

Because of Alphys's experimentations with DT, some petals and one of his eyes melted. He's closer to the ground than Classic.

In the current published material, he is scared by Frisk since the beginning, but spies her during almost all of the neutral route. Though he mainly does that, he also helps monsters on situations related to her, such as Monster Kid or Gaster. At the end, he absorbs the six human souls to fight Frisk, and though they accept to help him, he fails against Frisk and Zeno. His first appearance is in the first episode.

He is killed by Celerity in Xénotale: Celerity so only the members of the organization are in the timeline.


Main article: Toriel

Toriel was the former queen of the Underground and the mother of Asriel. During her reign, she welcomed Chara, who became a little crazy because of The Voice. Asgore started to kill Chara several times, and when Toriel discovered that, she divorced Asgore and took Asriel with her. Asriel died the next day.

Later in the ruins, she saw Flowey with the same symptoms as Chara. She inquired with Napstablook about this. She often spoke to Sans via the ruins door but one day she came out of the ruins and met him. From there, she began to come out of the ruins often to see Sans. But even later, she met Frisk and noticed that she scared everyone and wanted to stop her.

She wears a short dress with short sleeves and the delta rune symbol. Her eye is constantly burning. When she is angry or she is fighting she's completely on fire.

In the current published material, she receives and initiates Frisk normally, but when she understood Frisk had the same symptoms as Chara, she left her and sent Napstablook spy her. It's said in her diary that she thinks that Frisk is dangerous and said to Sans that he can use every method to stop Frisk, and that she doesn't mind if Frisk dies. She kills Frisk one time, but died on her second fight. Frisk also notices she can't be scared during the first fight against her. Her first appearance is in the second episode.

During the first bonus of Xénotale: Bonuses, she tries to talk with Sans just to fail. She then decides to do whatever is necessary to prevent the threat that is Frisk to go through the rest of the Underground, even if that means killing.


Main article: Napstablook

After Flowey arrived in the ruins, Toriel quickly noticed that he had the same symptoms as Chara in the past. She then asked Napstablook, who would be discreet, to spy Flowey and report back the information he got to her daily. He accepted. Since then he has been spying Flowey and reporting to Toriel every day. He can resign at any moment.

Since he works for Toriel he's in fire and he looks demoniac.

In the current published material, he fights Frisk because she knew that he were spying her. After being easily scared, he ran away, attacking with an extremely strong scare attack. However, he clearly understands Frisk's behavior and objective and said everything he knew during is report to Toriel. He is also the first who killed Frisk. His only appearance is in the third episode.


Main article: Sans

Sans is a skeleton who lives with his brother and obeys to the strict rules of his brother. Because of one of them, he no longer drinks ketchup. He is afraid of his brother, so he tries to hide Frisk from him, and ands up asking her to kill Papyrus. In the eidocide route, when he saw his brother -who was stronger than him- being killed by Frisk, he decided to train in order to defeat her. Zeno trained him. Though he died thousands of times during the training, Zeno revived him. Zeno eventually made him stronger after the training. Between the first and the second phase of the fight, an energy made it more powerful. Nevertheless, he ended up dying at once attack, doing infinite damage.

He is very afraid of his brother and of a part of the royal guard, however, he trusts Snowdin monsters. He tries to do a lot of things to kill his brother, like using people, but just wants to protect monsters from threats, but makes sure his plans go well. He dislikes being tortured and tries to save it from it, but accepts it when its unavoidable. However, he considers himself to have his priorities straight, and prefers to go warn Asgore and judge Frisk at the cost of being tortured more. To make sure Papyrus doesn't understand what he prepares, he helps him sometimes. He doesn't think Frisk can survive through Papyrus traps, but look at her in case she would. He shows to be way more afraid of Alphys than of Frisk, though the latter is a human that is far less predictable. He is good at analyzing, not hesitating to state that Frisk has done good, though he knows it was unintentional.

In the neutral and pacifist routes, he has the same appearance as Classic except his glowing eye only is yellow. In the second phase of his eidocide fight, a red energy envelopes him. He has a gash like the gash at the end of Classic!Sans's eidocide fight. In this phase his glowing eye is red.

In the current published material, he is first seen talking with Toriel about Frisk and the threat she is. He appears mostly during the Snowdin arc though, where he tries to make Frisk kill Papyrus, and fails at it. Papyrus decided to torture him because of that, but he reappears helping Gaster at Hotland because Papyrus accepted it, the last time by fighting Frisk with him. He last reappears in the judgement hall, where he judges Frisk, and doesn't reappear again. His first appearance is in the fifth episode.

In Xénotale: Bonuses, Sans goes to the art club headquarters to meet Gaster. However, Gaster has a hard time convincing him to help Frisk. He reluctantly helps Gaster with his plan afterwards. When he is back in the torture room, he teleports away to tell Asgore about Frisk and the threat she represents, as well as about the royal guards. He then goes to judge Frisk.

In Xéno!Papyrus's journey, after Papyrus's disappearance, he takes Frisk's soul. When Papyrus comes back, he doesn't hesitate to confront himself to him, being confident thanks to the power of the human soul. However, during this fight, he ends up being killed by Papyrus.

Toby Fox

Main article: Toby Fox

Toby Fox is a dog that tries to solve an issue in the universe. When Sans brings Frisk to him, he immediately thinks she's the issue because of her "scare" ability. His goal then is to kill Frisk. When he fights, Toby Fox can defend himself to nullify the damage.

In the current published material, Toby Fox is first okay to host Frisk at his home, but realizes the existence of the "scare" option. Though he decides to fight Frisk, he concludes that no one can beat the other. It makes him want to trap Frisk but he doesn't success. Later, wanting to take revenge on Frisk with the help of Gyftrot, he is arrested by Papyrus. He ends up being a part of the Gauntlet of Deadly Terror, placed there by Papyrus because he wanted to see her die. His first appearance is in the seventh episode.


Main article: Papyrus

A human apparently beat Undyne a recent day. She began to recruit all the monsters that passed, Papyrus included. He soon became the second in command of the Royal Guard, then began to scare all the monsters of Snowdin and Undyne. He enacted strict rules. If the monsters do not obey to Papyrus's rules, they are executed by Papyrus himself. He's the one who discovered the basements of the Underground. During the eidocide route, he steals some of Alphys's determination to kill Frisk, which transforms him at the beginning of his fight.

He is selfish, thinks he is above everything and likes to scare the monsters, especially Sans and Undyne. That makes most people hate him, excluding his followers. However, in the pacifist route, he has the same personality as Classic!Papyrus, with more regrets. He is shown to torture Sans often, but to also have respect for people that acts a bit like him. Grillby states he hated to see his brother drink ketchup constantly. He often says "Nyeh heh heh heh heh heh heh.". He often uses letters to tell messages, even if he can tell them directly. He hates disobedience and betrayal towards him, killing upon seeing it. He is also very serious when it comes to the behavior of the royal guard, though he can be understanding from time to time on a case-by-case basis.

Since he's in the royal guard he wears a royal guard armor (because of Undyne who command him to wear one). Because of one of his missions, he has a hole in his skull but a sharp spike is formed to replace his past bones. He uses it to execute people who don't obey his rules.

In the current published material, he is mentioned by Sans when he talks with Toriel, only to appear at Snowdin, trying to kill Frisk. Even if he tries through traps and by calling members of the canine unit of the royal guard, he eventually fails and becomes a friend of Frisk. He also decided to torture Sans, but frees him temporarily when he is needed by Gaster. He also speaks with the magic guardian after he gives the news to Sans about Undyne's soul. His first appearance is in the eighth episode.

He is very active on his phone, calling himself the determined guard to give him a mission in Xénotale: Bonuses, then to get calld by Gaster. In the bonuses as well, he continues to torture Sans when Gaster doesn't need him anymore. He sees an unusual escape from Sans after refusing to free him in the last neutral bonus.

He is the protagonist in Xéno!Papyrus's journey. After having killed Frisk, he escapes the universe where he is usually, meeting Ink!Sans, and Opposite later. Ink!Sans explains to him that there is a Multiverse, composed of many AUs, so, they both leave the Doodle Sphere to find from what AU Papyrus comes, which is the main goal of the story. Eventually, he finds out his origin AU and enters Zeno's organisation, which gives him the mission of separating Ink and Opposite. He succeeds at the mission in Undertale by imprisoning Opposite, using Error!Sans and convincing Ink!Sans.

He has a minor role in Xéno!Frisk's arrival, as a member of Zeno's organization. At first glance, he tries to kill Frisk but is explained that he was Frisk's only friend in the timeline the Frisk of the organization originates from.


Doggo is a dog that lives in Snowdin, but is blind. He works in a sentry post. When he smells someone, he attacks them and tries to kill them. He only fights using blue attacks. Due to him being blind, he cannot be scared.

In the current published material, Frisk moves near to Doggo and he attacks here. Since Frisk cannot scare him, she kills him. His only appearance is in the eighth episode.

Nice Cream Guy

Nice Cream Guy is a vendor of Nice Cream that doesn't have a flourishing business,a nd who avoids Waterfall because of what is happening there.

In the current published material, Frisk talks to him and he sells two nice creams to her, while explaining what happens to his business and how people uses nice cream to her. His only appearance is in the tenth episode.

Lesser Dog

Lesser Dog is a member of the canine unit of the royal guard, who is Papyrus's second trap to kill the human. Like the other members of the royal guard, his training makes him not being able to scare.

He is impatient when it comes to fighting a human, says "bark" a lot, and likes to explain why he is stronger than what people thinks.

In the current published material, he appears when Frisk finishes to read Papyrus's letter in the tenth episode. He fights Frisk, but is killed quickly. His only appearance is in the tenth episode.

Dogamy and Dogaressa

Dogamy and Dogaressa are two dogs loving each-other, and who are members of the canine unit of the royal guard, fighting the human when she passes the third trap. Like any other member of this unit, both cannot be scared.

For them, their love is above everything else, while they don't want to die. When they fight, they always fight together with the "power of love" and are worried if the other is harmed in any way.

In the current published material, Papyrus orders them to look at Frisk and attack her if she survives to the puzzle containing the third trap. Eventually, when she passes it, they congratulate her and attack her. Unlike Lesser Dog, they attack Frisk because they are more robust, but end up dying during the same turn. Their first appearance is in the tenth episode.

Greater Dog

Greater Dog is the last member of the canine unit of the royal guard Frisk fights, who resists to the attacks easier. Also, he cannot be scared.

He likes his companions, and explains to Frisk they were doing their job. For him, they were killed without any reason to it, but he never forgets his job, as he states he would have attacked Frisk anyways.

In the current published material, Frisk meets him before going to the last trap, and he fights her mostly to avenge his companions. After attacking once, he dies. He only appears in the twelfth episode.


Main article: Grillby

When Papyrus abolished ketchup, Grillby's trade closed but Grillby still had his ketchup bottles. Not knowing what to do and having to get rid of the ketchup quickly, he decided to drink all their content. Grillby has drunk so much of it that he ended up turning all his fire into ketchup. Since this moment, everyone turns around him to drink his ketchup, but drinking ketchup was forbidden so it's useless. The monsters have however always gone around Grillby, even if he hates that.

In the current published material, he closes his bar after after the execution because he feels bad for the monster that was executed. He tells Frisk about the Papyrus's laws that are related to ketchup and about a bit of his story. His first appearance is in the fourteenth episode.

Royal guards 01 and 02

The royal guards 01 and 02 are two royal guards who often abuse of their power of royal guards, and who often attack Monster Kid, without forgetting their duty.

In the current published material, they attack Monster Kid when Frisk meets them. She gets their attention then fights them. Like for Dogamy et Dogaressa, she kills them during the same turn. Their only appearance is in the seventeenth episode.

Monster Kid

He is a basic Snowdin inhabitant, but he doesn't understand many things, such as Papyrus's laws or the hate that monsters devote to Papyrus, who, as a royal guard, protects them. However, he hates the other royal guards, who torture him for Papyrus, who doesn't have the time. Even with that, he doesn't really understand what is happening. Monster Kid studies the story of the Underground, and when he encounters Frisk, who saves him from the royal guards, he follows her throughout the entire Waterfall arc. During this arc, he tells to Frisk the story of the royal guard. Frisk finds him annoying, say that he's pestering her but also say that what he's telling about is interesting, and Chara uses this information during the pacifist route. Monster Kid isn't fightable, and Frisk wants to know why. She has the answer in the eidocide route, when Zeno transforms him and make him stronger, which make her fight Monster Kid.

In the current published material, Frisk saves Monster Kid from the royal guards 01 et 02, which makes him deicde to follow her. Following Frisk actually helps Frisk, most notably through the puzzles. While they are both together, Monster Kid also tells Frisk stories about the Underground, but they separate at one point. They eventually meet again, but at this moment, Frisk kills him. His first appearance is in the seventeenth episode.

He makes a brief appearance in Xéno!Papyrus's journey, where he meets Celerity. He first confuses him with Sans, but Celerity responds to him that he isn't Sans. Celerity asks him where Papyrus is, and Monster Kid answers that Papyrus has disappeared because he has something to do since Sans is dead.


Many years after Asriel's death, Undyne became the head of the Royal Guard. Asgore told to her what he did et why he did all that, so, she discovered the power of the determination. However, she didn't know if she'll help him or sent him in jail. She decided that she'll decide about that when she'll have a human soul. After that, she encountered Zeno. She thought he was a human and fought him. She lost the fight, but didn't die. After that, Zeno became the threat of the Underground. She was afraid that he can try to ruin the plan to free the monsters from the Underground, so she began to recruit any monster that wanted to be. She also recruited Papyrus, who, because of his power, became the second of the royal guard. He wasn't as powerful as Undyne, but rally many royal guards to his causes, enough to dismiss Undyne from her role of head of the royal guard. Since that, she work on her side until she encounter Frisk.

She is afraid of Zeno and Papyrus, and is hesitating often about what his the right choice about Asgore. She is also feared about Papyrus becoming the head of the royal guards. She hates the power of the determination in bad hands. When Frisk fights her, she can't escape the fight, because the exit was blocked by Zeno. That means to spare her, she has to use the scare act.

In the current published material, she hunts Frisk down for being a human, while fighting the evil royal guards all along, because they try to kill her. At one point, she has a fight against Frisk slightly forced by Zeno and survives to it, but is weakened so much that she is killed by the determined guard. Her first appearance is in the eighteenth episode.

Mad Dummy

Mad Dummy is a ghost who possesses a dummy, cousin of the ruins Dummy, who wants to merge with his body, and who lives the garbage dump of Waterfall.

They are a ghost who cares about their family. They are easily heated and fights often because of that. During a fight, they use the help of other dummies, robots and knives, as well as dodging magical attacks. They do not hesitate to insult them and to say mean things, which they tend to scream thrice in a row.

In the current published material, they fight Frisk in the garbage dump of Waterfall. While they use the help of other dummies, they end up getting more damaged than Frisk. They fire them then use the help of robots, then it happans again. The fight ends because they do not have anything to attack left, and while they want to trap Frisk forever, Frisk just leaves them. Their only appearance is in the twenty-second episode.


Riverperson is a person who doesn't want to tell people their sex, and who makes people travel with their bot, regardless of their sex or species. This person, from what Frisk knows, can go from Waterfall to Hotland.

Riverperson likes to seem mysterious, and to say sentences that have meanings only for those who can understand them. Riverperson likes to say "Tra la la.", and seems to know what Frisk does.

In the current published material, Riverperson sees Frisk and proposes to her to go to Hotland. She accepts. While they are on the boat, they say a sentence that seems to have no meaning, saying that they were asked to say it. After some time, they push Frisk from the boat to kill her. Their only appearance is in the twenty-third episode.


Gerson is a turtle who sells items in Waterfall, and who thinks that the business is a priority, even if he needs to sell to someone he hates.

In the current published material, he meets Frisk when she tries to buy items from him. Though she fakes kindness, he sees it immediately, but still sells her crab apples. His only appearance is in the twenty-third episode.


The Temmies are a race of monster that shows most of his members as idiots at an extreme point. Because of that, they don't fear anything. They talk in a very unusual manner.

In the current published material, Frisk fights a Temmie she meets just after she buys items from Gerson. She kills it. Later, the determined guard and his group go to the Temmie village, where they kill all members of the race. Their only appearance is in the twenty-third episode.


Alphys created Flowey in the past. Flowey was so scared of The Voice that he was squatting at Alphys's lab, but Alphys turned him constantly. When he wanted it to not happen again, he destroyed Alphys's soul. In order to survive, she then took pieces of the six human souls guarded by Asgore and quickly created an artificial soul with them, which gave her determination and its powers. She became obsessed because of these powers and of The Voice, but when she lost them, she wanted to find them and went crazy. She is constantly trying to trap Frisk using Mettaton or normal traps.

Alphys is a cruel person, wants absolutely to have the power of the determination, even if she has to kill many monsters for that. However, she can have a good side, still helping Mettaton for his shows, and can just show herself being passionated by science. She is also stated to be extremely strong, capable of killing Toriel or burn her laboratory in a single attack[1][2] and kill Papyrus in two attacks, due to her melange soul[1]

When Flowey attacked her, he drilled a hole in the middle of her body. After that, she replaced her past soul with a new soul. Her soul is a soul with a giant hole in the middle but with pieces of the six human souls guarded but Asgore turned towards the exterior. Because of her experimentations on determination, a part of her head has melted.

In the current published material, she doesn't do many things besides forcing Mettaton to get Frisk's human souls and helping him with his shows, but her traps kill Frisk a lot of times. She also runs the oblivion prison, where she brings every person who enters the CORE, including Frisk. That causes her to fight Gaster, who wants to free Frisk from it, though they both come back at her laboratory. She eventually returns to her laboratory, seeing the fight between Frisk and Mettaton, more worried about Phobos. Her first appearance is in the twenty-seventh episode.

In the seventh bonus, while she is fighting Gaster, she is interrupted by Phobos, who reveals his plans to her. That causes her to go back to her laboratory.


Gaster went away from the void helped by Zeno. He then helped Alphys during his experiments as a scientist. One day, there was an accident and some determination melted a part of his skull. He helps Frisk pass Alphys's traps in the neutral and pacifist routes. However, Gaster merges with Sans after having fought and beaten Muffet, and fights Frisk afterwards. During the eidocide route, he seems absent, but before the Last Corridor, he fights Frisk, which can make her unlock the True Axe.

He looks like the Undertale Mystery Man but more solid. Because of Alphys's liquid determination tubes and a lack of attention, a part of his skull melted.

In the current published material, The Voice tells a written story about him. In this story, it is written that Gaster is the one who caused the war between the humans and the monsters by killing a human for one of his experiments. It is also written that he is the one who discovered how to destroy the barrier. A bit later, it is told that he has been thrown in a part of the CORE so he could die or be imprisoned, then that everything has been done so he could be forgotten. He appears later, as one of Alphys's helpers, though he decided to help Frisk to survive, by updating her phone but also by telling her how to survive to Alphys's traps, by training her to fight or by freeing her from the oblivion prison, which causes him to fight Alphys. Though she is strong, he survives and goes back to Alphys's lab with her. His first appearance is in the twenty-seventh episode.

In the seventh bonus, while he is fighting Alphys, he believes he can't beat her. However, Phobos interrupts their fight to reveals his plans to them.


Mettaton is a ghost inside of a robot body created by Alphys. In the past, both were good friends, even before the robot body had been created. Eventually, something happened and Alphys forced Mettaton to help her, at the point where he is considered by Gaster as "Alphys's slave".

Not much is known about how Mettaton was like before he was imprisoned in his robot body, but something sure is that he desperately wants freedom since then. Besides that, he still dreams to become a star, though he knows that it will be difficult. He gretaly considers what the spectators of his shows want, and wants to content them. Though he knows about the existence of timelines, he prefers that the spectators do not know about it, but likes to trick people into saying it, and even saying a lot of things for his shows.

Under his normal robot form, he looks like a box with two arms, two legs and two wheels for moving. His main color is yellow, which is caused by Alphys's electrical magic. Inside his body is also electrical magic from Alphys, invisible from outside. The main reason for that is to trap the ghost inside the body. His Mettaton EX 2.0 form is different. He is much more anthropomorphic, though is main color is still yellow. Under this form, as he sacrifices some part of the body to heal, he can be seen armless, or even armless and legless.

In the current published material, Alphys calls her to kill Frisk. However, his attacks are unefficient, so Gaster comes with the idea of letting Frisk go for a time. During the time he doesn't appear, he prepares his shows with Alphys's help, and Frisk goes through three of these before she goes to the CORE. When she fights him in the CORE, he uses his new update, the Mettaton 2.0 form, but he fails to get her soul. His first appearance is in the twenty-seventh episode.


Muffet is the spider who leads most of the spider bake sales in the Underground as well as the spider safety program. Like all other spiders from this program, she is an inhabitant of the Web, and she self-proclaims herself to be one of the strongest spiders in the Underground, though she is beaten by Gaster.

As shown before she meets Frisk, Muffet sells her bakery at a very high cost, though, she is not a miser. In fact, she does this only to have enough money to free the spiders from the ruins. However, though she cares about getting money, she thanks people by selling her bakery for less money.

In the current published material, Frisk meet sher for the first time just before she fights Aster. However, she survives Aster, and Muffet thanks her by welcoming her in the Web, and by selling her her bakery for the normal ruins price, as well as giving her a mysterious key she does not end up using. Her first appearance is in the thirty-sixth episode.


Asgore Dreemurr, also known as Der Schlächter is the king of the Underground. In the past, when he discovered the power of determination, he did not stop to kill Chara. His LOVE gain has strangely gone through the timelines. When Toriel and Asriel discovered what he did, he finished alone. He then continued his work as a king while regretting his past actions. In the eidocide route, Asgore runs to the barrier to flee Frisk, after Flowey tells him that she's very dangerous. When he is blocked by the barrier, the six human souls decided to help him and he has the benefit of the God's help.

Because of Chara's death, he has blood on his clothes. He has some dials on some parts of his body because of temporal problems. His crown is made with black flowers.

Asgore is a wise monster, knowing that what he has done in the past was wrong, and who deeply regrets his actions. His regret makes him inactive as a ruler outside of New Home. He sees his duty as getting the human souls to free the monsters before everything, even the well-being of the monsters themselves. When he fights, he doesn't show himself to fight the best at the beginning intentionally, and instead does it when it becomes more dangerous to do so. He believes that a voice is responsible for everything that happened because of Frisk, and has a hard time believing its victims. Though he does not show it, he has a great capacility to analyze what people think about him.

In the current published material, Frisk meets Asgore for their fight. Asgore mentions that Sans has told him about her, and then they fight. Though he succeeds in killing her once, he eventually dies during the second fight. His first appearance is in episode 50.

He makes a small appearance in Xénotale: Bonuses, in which he is told by Sans about the threats that may fall on him.

He is killed by Celerity in Xénotale: Celerity so only the members of the organization are in the timeline.

Added Characters


Main article: Aether

Aether is a skeleton that appears during the end of Xéno!Frisk's arrival, along with his brother Erebus. There, he finds out his father is dead, and vows to avenge him. During the story, he takes control over Opposite!Sans, and fights against Xéno!Frisk and Celerity!Sans.


Main article: Alpha!Sans

Alpha!Sans is a Sans who is known only by a few persons, and who also isn't visible by a lot of persons, helping the protector, while giving them information about what is happening in the Multiverse. However, he sometimes needs to do it when there is a public with them, and so needs to erase some of the memories of the public afterwards. During the story of Xénotale: Celerity he is stated to be someone who mostly takes information to give them to the protectors. During this same story, he states that Infected!Sans has destroyed his AU during the Outertale slaughter.

He is a bit curious, wanting to know why Celerity must do some actions he hates, though he gives his confidence to him. He takes his mission of protector of the AUs extremely seriously, telling Ink over and over that this is his duty. However, he likes spending time with his friends and helping inhabitants of the Multiverse, whoever they are. He is extremely trustful in Celerity most of the time, though he shows mistrust during Xénotale: Celerity. He is described by Blueberror to spend a lot of time with Ink!Sans, but less with Blueberror himself. Alpha!Sans likes honesty, though he sometimes seek it so much that he can be seen as impatient. He doesn't fear much, though he does fear Infected.

He is important in Xénotale: Celerity where he is the protagonist's best friend. He is the one that presents Celerity the protectors, and who tries to make Celerity!Sans a protector, though Ink!Sans refuses all the way. During the story, he eventually finds out Celerity is working for an organization, and what this organization exactly does, though some secrets are kept from him. He also helps the protectors during that story, most notably by getting informations about recent events.

In Xéno!Papyrus's journey, he often makes only brief appearances. When he first appears, he alerts Ink!Sans that Error!Sans tries to destroy an AU, then teleports Ink to Error. He reappears later, talking with Ink!Sans again, telling him he needs to protect Papyrus while giving him more informations about The Voice. He talks again later, with Celerity this time, but they are both watched by Error!Sans. When Papyrus uses yellow magic, he is obligated to erase the memories of those who saw it. When Papyrus disappears, he tells Ink that Papyrus has disappeared instantly. After a come back of Ink!Sans, Opposite!Sans and Papyrus in Underfell, he talks with Ink!Sans about a strange event. During his last appearance, he talks with Celerity, and they both end up helping inhabitants of AUs.

Armored Guard

Main article: Armored guard

The armored guard is an elite warrior of the royal guard who is on Undyne's side, and who seeks to get a human soul to end Papyrus's reign of terror. They got their nickname of the armored guard because no monster but Undyne have seen them without armor, because they seem invincible in the first place.

Since they are on Undyne's said, they hate Papyrus and his followers, and tries to stop them. They like monsters a lot, and wants to protect them at all costs, even if they need to follow Papyrus's laws in Snowdin. They like to give lessons during fights, even if the fights become harder, and tends to underestimate their opponents. Rarely, they can be panicked, but are also prepared in these cases, and they rarely use their yellow attacks. They are confident over their abilities, and are determined to kill Frisk. They hate Frisk because of what they do and think that, if they let her continue, it will end very badly for the monsters. They don't accept defeat, as well as not wanting to deceive the monsters, eventually using their hope to convince themself to continue to fight.

In the current published material, they see Ice Cap fleeing Frisk, and asks him what he is doing. They burn him and attack Frisk. During the fight, Frisk discovers that the armor is their weak point, and when it is about to break, they flee to prepare themself. They return to fight Frisk just after she passed the Gauntlet of Deadly Terror. Being prepared, they have two armors they can turn into a shield. They killed Frisk, but her returning made them fight her again, without any memory of the fight in the previous timeline. They die by melting because of the determination they have. Their first appearance is in the ninth episode.


Blueberror, often nicknamed Blue, is one of the protectors of the Multiverse, though he isn't seen as much as Ink!Sans or Alpha!Sans. He is a Sans from Underswap that has been abducted by Error!Sans and who has been corrupted by the anti-void 6 afterwards.

More often that Ink!Sans thinks he should, he is excited, especially by new people, at least as long as it isn't dangerous for the Multiverse. However, he can retain his seriousness, most notably when destruction or rare events are happening in the Multiverse. He shows jealousy towards Ink!Sans and Alpha!Sans's friendship, and seems to hold a good relationship with Error!Sans, deeply wanting for him to be his ally. He is also very merciful, even when it comes to dangerous enemies, and does not like to force people to not do what they do want. He also hates to be slow while traversing the Multiverse, and thinks of himself as someone who can do better.

In Xénotale: Celerity, he is presented along with the protectors, but he doesn't do much during the beginning of the story. However, later, he organizes an official Outertale meeting and gets information for it, though he doesn't lead it. After the end of the Outertale meeting, he is with the other protectors when The Voice appears, and contacts Error!Sans on this matter. He doesn't appear afterwards.

In Xéno!Frisk's arrival, he is one of the two persons to introduce Xéno!Frisk to the Multiverse, though he is confused with Error by her. He also participates to the battle in Underswap, where he gets his skull severely injured.


Main article: Celerity!Sans

This Sans is a normal Sans who lived in a eidocide timeline. He fought Frisk after the training created by Zeno and won the fight during its second phase. After that, the energy let him continue to become stronger. He started traveling throughout the Multiverse and working for Zeno as his strongest fighter and second in command afterwards.

This Sans wears a jacket with blue and orange specks. His left eye is yellow and his right eye is polychromatic. He has a crack on his left eye. His soul is polychromatic as well, though it is a fragment of Zeno's old soul turned into a complete soul, which he doesn't know. During Xénotale: Celerity, he gets his clothes from Innovation!Sans.

He is the protagonist of Xénotale: Celerity, the story that shows the beginning of Zeno's oragnization, but that also explains his story as well as his progression in the Multiverse. His first action, though not shown, is to win the Multiversal Sans tournament, before he meets Zeno again. Zeno tells him about several specifics of the Multiverse and invites him to join his organization, which he accepts. He is given missions though he does dislike most, which progressively breaks him during the story, but it also helps him to discover how everything works in the Multiverse, and makes him stronger. Dreaming to become a protector, at the end of the story, he fights Zeno but loses the fight. However, after the fight, Celerity sees Zeno the most emotional he has seen him, the latter telling the former why he acted the way he did. Zeno also tells him that Celerity is the creation he is the most proud of. After the discussion, Celerity stays in the organization, but also leads the protectors to Infinitetale.

In Xéno!Papyrus's journey, he is first mentioned by Alpha!Sans, and appears talking with Alpha!Sans. He reveals to his friend that Papyrus comes from Xénotale. Later, Zeno orders to Celerity to bring Papyrus to him. To succeed, Celerity offered answers to Papyrus, but also made him go through a trial. He brings Papyrus in Zeno's HQ after this trial. During the announcement of the results, Celerity is present but doesn't say anything. When Papyrus has left, Zeno tells him who will be the next recruit, then he goes helping inhabitants of the Multiverse of with Alpha!Sans.

He also appears in Xéno!Frisk's arrival, where he is the one to introduce Zeno's organization to Xéno!Frisk, and who explains to her what her mission is. He does not act much in this story, though he is the one to fight Aether and Erebus in the end.

Corrupted Justice Sans Aster

Corrupted Justice Sans, sortened as CJ!Sans, is the Sans from an AU known as Corrupted Justice. In his AU, he is the royal scientist, as well as an inventor, and someone who helps the protectors when he appears.

Sans is a lazy scientist, often quitting his big experiments out of laziness. he still actively studies is other universes, although while having discovered they exist he has not found a way to get to them yet. He used to watch Papyrus on his monitor, but after his brother changed due to his experiment, he couldn't get himself to look at him anymore, now only having very surface-level conversations with him via the undernet. He lies to himself his brother is alright, pulling up a façade of happiness towards everyone else and seeming like his classic self on the surface, although this facade falls when Papyrus is brought up. He is often seen inventing remote controlled machines, something he started to build as a distraction to not think about what he did to his brother and now really enjoys making.

In Xénotale: Celerity, he meets Celerity!Sans, someone from another universe, and finally gets a part of his goal, more accurately, to have contact with other universes. He later gives Celerity an EXP absorber he constructs during the story for the protectors. He also appears during the Outertale meeting, though he doesn't say much.

Determined guard

The determined guard is an elite warrior of the royal guard who is on Papyrus's side, who has been sent by him to kill Undyne and take control of the Waterfall territory, and who uses the Temmie village as a base for his operations. He obtained this nickname because of his favorite weapon, a determination stick that absorbed Alphys's reserves of determination, and that he uses to kill via an injection of determination into the monsters.

As he is on Papyrus's side, he hates Undyne and his followers, including the armored guard, and he tries to kill them. He likes to have control on the Underground and on the royal guard. He doesn't hesiate to kill for multiple reasons, such as disobedience, for inhabiting a place he wants or just to get someone's attention. However, like Papyrus, depending on the case, he may pardon someone, though it is very rare. The only person he obeys to is Papyrus, and he lets the persons Papyrus choose survive.

In the current published material, he gets Frisk attention by telling his group that he want sto go in the Temmie village. Frisk follows him and there, he organizes a genocide of the Temmies. He then calls for Frisk, tells her what happens and who he is. After these explanations, he lets Frisk continue with the mission of either killing or weakening Undyne. His first appearance is in the twenty-third episode.

He has a role in Xénotale: Bonuses, in which he is called by Papyrus to protect Frisk just to use her. In the bonus that happens mostly while Frisk and Undyne are fighting, he sends the royal guard 23 to spy on the fight. When this royal guard is back, they suggest to go to Undyne quickly, which the determined guard agrees with. Later on during the bonuses, he calls Papyrus to describe Undyne's death.

Dusttale Frisk

Dusttale Frisk, shortened as Dust!Frisk for the Out!Codes, is the Frisk from Dusttale as well as one of the two serial killers who fight in the AU since the beginning of its existence, along with Murder!Sans.

Dusttale Frisk looks like human child who wears a blue shirt with pinkish purple colored stripes, blue pants, and brown shoes. They have medium-length straight brown hair, short and choppy bangs, and a blank expression most of the time. They also have a lot of dust on them.

Dusttale Frisk is a human that finds pleasure in killing.

He briefly appears in Xénotale: Celerity where he is killed by Celerity!Sans because the latter didn't want them to bother Great!Sans and Murder!Sans during their fight.


Main article: Erebus

Erebus is a skeleton that appears during the end of Xéno!Frisk's arrival, along with his brother Aether. There, he finds out his father is dead, and vows to avenge him. During the story, he takes control over Opposite!Sans, and fights against Xéno!Frisk and Celerity!Sans.


Error!Sans is an AU destroyer who lives in the Anti-void 6, whose goal is to protect Undertale. So, he destroys the AU because he thinks they are ill-fated for its existence. He is Ink!Sans's main enemy, whose goal is to protect the AUs, as well as the most known AU destroyer of the Multiverse.

He hates everything that doesn't originate from Undertale, especially Ink!Sans, though he stays calm most of the time. As soon as he feels something unusual in Undertale, he instantly goes there to find out what it is, and takes care of it if it is necessary. He hates to have blankouts, though it happened multiple times. Even if he hates everything that doesn't originate from Undertale, he is clever, knowing that he can only submit to someone stronger than himself, or ally to other destroyers if he considers it has an interest. Though he prefers that any change in Undertale, even minor, is non-existent, if he needs to do it, he will not hesitate to control any inhabitant of Undertale, mostly during a fight. However, since he has determination, he cannot control himself when he hears The Voice.

Error is a black glitchy skeleton with a color palette mainly consisting of dark reds/reds, dark blues/blues, yellows, oranges, and blacks. He has two unsymmetrical eyes, one a small yellow pupil and the other is a circle with yellow, blue and black. He usually needs to wear glasses because of his eyes being messed up from when he was Geno but refuses to wear them sometimes. He wears a black hoodie, a red shirt, black shorts, and black slippers.

In Xéno!Papyrus's journey, he first tries to destroy an AU, only to be seen by Alpha!Sans. Ink!Sans prevents him from destroying the AU. Not a long time after this, he feels a strange activity in Undertale then tries to find out what it is. After having heard a conversation, he finds Ink!Sans, Opposite!Sans and Papyrus. Since they aren't supposed to be there, he fights them, then fails at beating them. When Ink!Sans and Opposite!Sans find Papyrus back, he is in Outertale to look at the space. They find him there and interrogate him, but his answers are unsatisfying. Later, Ink!Sans, Opposite!Sans and Papyrus stumble upon him with XGaster. He tells them that not making an alliance with him would be stupid, then fights them with XGaster, both becoming stronger thanks to The Voice. When the fight ends, he has a conversation with Ink!Sans, then Ink!Sans leaves. He ends up being controlled by The Voice to help Papyrus in his mission.


Great!Sans ia a Sans that originates from an AU called Greattale. He is a person who admires Celerity!Sans due to his performances during the Multiversal Sans tournament, and whose main goal is to train to become stronger. According to Opposite!Sans, he is a member of G's order.

He looks like the standard Sans, though he has a glowing grey eye as well as one arm.

He appears in Xénotale: Celerity, being the reason Celerity can't destroy Dusttale instantly. Due to this, Celeirty helps him getting stronger by locating Murder!Sans. Great!Sans and Murder!Sans then fight until Great!Sans until he decides to stop and to leave the AU. He reappears during the Outertale meeting, in which he almost fights Opposite!Sans. However, Zeno stops them by using his powers to modify everyone's memories, excluding his and Celrity's.


A character who only appeared in the bonuses of Xénotale: Celerity, who was called by Zeno only to fight Celerity in a blank universe. Later, Zeno came to his territory to fight him and present himself. Zeno won the fight and then went outside of H's territory.

H is seen extremely powerful and smart during his few appearances. He also states to be at least 60000 years old, and to not have access to all of Celerity's thoughts.


Ink!Sans is a protector of the AUs who lives in the Doodle Sphere, as well as the second character of point of view in Xéno!Papyrus's journey. He is Error!Sans and XGaster's main enemy, and is the most known protector of the AUs in the Multiverse. He is the owner of the Multiverse map and of the Doodle Sphere.

Ink!Sans is a curious skeleton when it comes to things he doesn't know about, so much that he sometimes makes his curiosity a priority towards his duty, even if Alpha!Sans tells him to do the opposite, which he finds annoying. When someone mentions an element that approaches the existence of a certain "King", he makes sure to say ambiguous things unless if it is with Error!Sans if they are alone. He is ready to protect his secret at any cost, even if he needs to kill. Ironically, he hates killers. He doesn't hesitate to lie to his companions to make sure the existence of some persons isn't revealed and, at the end, considers Opposite as dangerous for him. He is extremely meticulous in what he does, making sure he doesn't forget any detail each time, even if it is long, panicking if what his happening doesn't go as he wants.

Ink has ink on his right cheek. His eyes are usually a blue circle in the right eye socket and a star in the left. He dons a long-sleeved, white undershirt with a small brown jacket over it. His pants are actually overalls with the tops tucked into his waist. The legs are very wide at the bottoms, with creases around the legs. He also has no shoes, instead, he goes barefoot with a pair of leggings. Always near of him, he has brush called Broomie. He is also very small.

In Xéno!Papyrus's journey, he is found by Papyrus in the Doodle Sphere. After the revelation from Papyrus that he doesn't know what the AUs are, he tells him what is the Multiverse, and how it is composed. After that, they both leave the Doodle Sphere to find from what AU Papyrus comes. However, Ink needs to protect an AU from Error!Sans, and so, leaves Papyrus in Underswap. When he returns in Underswap, he realizes that Papyrus has left the AU. He seeks him until he finds him in Undertale with Opposite!Sans. When he finds them, they all talk which makes Ink!Sans and Opposite!Sans realize that Papyrus and The Voice originate from the same AU. Error!Sans finds and fights them. When the fight ends, Ink!Sans tells Papyrus that the yellow magic indicates the AU he comes from, but his memories are erased, as well as Opposite!Sans's, Papyrus's and Error!Sans's. To heal Papyrus, the three go in Underfell but him and Opposite are abducted by XGaster. Ink deals with XGaster so him and Opposite can escape to look for Papyrus then leave. He decides to protect Papyrus but when he disappears, him and Opposite seek him. Way later, he finds Papyrus back in the Doodle Sphere then they continue to search what AU Papyrus comes from. Though the search was unsuccessful, Opposite realizes that Underfell still exists, then Ink brings them there. There, they look for XGaster. They take a long time to find him, only to find him with Error!Sans. Him, Opposite!Sans, Classic!Sans and Papyrus fight Error!Sans and XGaster, but Ink organizes a withdrawal in Undertale. After that, Ink talks with Error then goes in Undertale to find his companions. He finds Opposite imprisoned, watched by Error!Sans. Ink then fights Error but fails. He then searches Papyrus then realizes he is a murderer and fights him. After an abandon, he returns in the Doodle Sphere.

Magic guardian

The magic guardian is a character mentioned in the thrity-second's episode of Xénotale by Sans and Gaster, though first mentioned by title by the royal guards 17 and 18 in the thirty-fourth episode.

She is a person who wants to keep the mystery about her, to the point where almost all royal guards have never seen her, and most do not known what she looks like. Like the other royal guards, she is interested by Frisk, though she does not explain why. She shows intelligence, knowing how people will react to what she says or even quickly analyzing situations during fights. However, she does not wish to fight much. She knows that she leads the royal guards 17 and 18 to their deaths, though she claims it is not for nothing.

She has her own bonus, in which she calls plenty of royal guards to tell them of the situation, then to give those who want the mission to fight Frisk. When they all leave, she speaks to herself about timelines, which she calls "time alterations", and gets frustrated because she does not remember them.


Murder!Sans is the Sans from Dusttale, and one of the two serial killers from this AU that fight during the beginning of its existence, along with the Frisk from this AU.

Murder!Sans is a skeleton skeleton that wears an unzipped blue hoodie, a white shirt, black shorts with white lining, and a pair of white slippers. He always has his right eye closed, but his left eye stays open. The iris of his left eye is mostly red, but with light blue towards its center.

Murder!Sans is obsessed with killing Frisk once and for all, at the point of killing the monsters and becoming like them just to stop them. He also has multiple mental diseases becuase of this, and sees hallucinations of his brother in the timelines he kills him in. He still can feel regret because of his actions, and though he kills the monsters of his AU, if other beings from other AUs appear before him, he doesn't want to do anything with them, even killing them or get their help. He wants to do his mission alone.

He makes a brief appearance in Xénotale: Celerity, where he is manipulated to fight Great!Sans. Upon Great!Sans ending the fight, Celerity!Sans kills him.


Main article: Opposite!Sans

Opposite!Sans, often called Opposite, is a Sans who studies the AUs, with an extensive knowledge of them, though he prefers to study them instead of protecting them. He escaped the place he is born in because of his parents, then met Ink!Sans in Outertale, who is the one who made him want to study the AUs.

He is kind and never attacks anybody without reason. He can be very sympathetic. Even if he tries to have friends, he is depressed when he thinks about his parents, even if he left. Opposite seems to be extremely curious, though he knows to abandon his questions when he knows he will never get any answer. He also seems to be able to keep being calm during tedious situations. Though, if someone threatens Underswap, he does everything that person wants him to do. Being in Outertale makes him nostalgic.

In Xéno!Papyrus's journey, he meets Papyrus in Underswap, his favorite AU. Curious of knowing the AU he originates from, he accompanies him in his research. They both go in the Multiversal Void, but flee in Undertale because of an Anti-void. Later, they meet Ink!Sans again then Ink and him realize that Papyrus and The Voice come from the same AU. Not long afterwards, Error!Sans find the three, which leads to a fight. Since Papyrus needs to heal, him, Papyrus and Ink!Sans go in Underfell. They look at the monsters during a moment then Ink and himself are abducted by XGaster. Later, Ink, him and Papyrus go in an Anti-void, leatting Papyrus alone while Ink and him do researches. Papyrus disappears, which force Ink and him to look for him. Later, after they found Papyrus and went in Outertale, Opposite brings them in the Multiversal Void, and he sees that Underfell is still there. Because of this, they go there, seeking to find XGaster. They find Error!Sans and XGaster thanks to Classic!Sans, then the four fight them. When Ink!Sans organizes a strategic withdrawal, him, Papyrus and Classic!Sans go in Undertale. After letting Classic!Sans, Opposite!Sans brings Papyrus to a place they could be hidden, only to be imprisoned. After that, he doesn't do anything until he is freed, and when he is, he goes in the Multiversal Void.

Outertale Asgore

Outertale Asgore, also known as Outer!Asgore by the Out!Codes, is the king of the monsters in an AU where the monsters are not in an Underground.

In Xénotale: Celerity, where he makes his only appearance, his AU undergoes an attack done by Infected. He attacks Infected to defend the monsters, but dies quickly.

Outertale Frisk

Outertale Frisk, mostly known as Outer!Frisk by the Out!Codes, is a human in an AU that happens in space. They do not know about Out!Codes though their AU is very visited, and also have a sex that varies depending on the timeline.

Her only appearance is in Xénotale: Celerity, in which she is female. Sans accuses her to want to help Infected, who prevented her from manipulating the timeline. When Infected kills the Sans of Outertale, she is abducted by Infected so he can have "fun" with her.

Outertale Sans

Outertale Sans, mostly known as Outer!Sans by the Out!Codes, is a monster of an AU that happens on an unknown place in space.

He appears in Xénotale: Celerity, in which his AU goes under an attack from Infected, he blames the Frisk of his AU for it, only to discover that Infected is the only responsible person for the damage. He fights Infecetd but dies.

Outertale Undyne

Outertale Undyne, also known as Outer!Undyne by the Out!Codes, is the captain of the royal guard in Outertale, an AU liked a lot of the Out!Codes.

She appears in Xénotale: Celerity, in which she tries to gain time for the monsters to flee Infected by fighting him. the fights turns short, and she dies in extreme pain.


Phobos is a mysterious being that appears in the Snowdin arc and the Oblivion prison arc of the main story. Not much is known about him, except for the fact that he wants to help Frisk for reasons he does not reveal to her. However, it is to either save or destroy the universe. According to the author, he is "insanely powerful".[2]

Capable of shapeshifting, Phobos is great at scaring people, scaring even Frisk when he is properly presented for the first time. He is not fond of killing others, though he understands it when he deems that the person has good reasons, such as surviving. He always talks of himself using a royal we, and sometimes shows himself to believe he is superior to others.

In the current published material, he first comments the execution at Snowdin, but disappears just after. He reappears in the Oblivion prison where he helps Frisk beating the soular knights and Mettaton. He lastly appears after the destruction of the Barrier, claiming he affected Frisk's journey throughout the Underground more than she thoughts. His first appearance is in the fourteenth episode.

He makes a reapparance in Xénotale: Bonuses, where he tells his real goal to Alphys and Gaster, which is to save or destroy the universe, saying he observed it and that he came to this conclusion. He then leaves.

Royal guard 23

The royal guard 23 is a royal guards who works for the determined guard. He is mostly known to get information for him.

In the current published material, he tells the determined guard as well as the royal guards with them what he has seen from Undyne's fight with Frisk, then makes sure to save the infromation on Undyne's soul. His first appearance is in the twenty-sixth episode.

He has a bigger role in Xénotale: Bonuses, in which he is sent to spy the fight between Frisk and Undyne by the determined guard, though he does not see much. He is also the one to give the idea to the determined guard to go see Undyne. He is present in the reunion done by the magic guardian, though he is inactive. There, he reveals that he knows what she looked like and that he constantly has notes on Frisk.

Royal guards 09, 10 and 16

Secondary characters that appear in Xénotale: Bonuses. They both try to kill the magic guardian, but she pushes them in the magma effortlessly. Royal guard 09 is more direct in their words, whereas royal guard 16 is much more hesitant.

Royal guards 17 and 18

The royal guards 17 and 18 are royal guards that fight Frisk for the magic guardian, though they die at the end of the fight. Their first appearance is in the thirty-fourth episode.

During the sixth bonus of Xénotale: Bonuses, the royal guard 17 is the one to accept to go fight Frisk after almost everyone thinks it leads to a guaranteed death, the royal guard 18 following quickly.

Soular knight of bravery

The soular knight of bravery is one of Alphys's six soular knights, more specifically the one that has a bravery soul in themself.

In the current published material, they are the third soular knight Frisk fights, and the second one she beats, and introduces to her the way the bravery soul works. Their first appearance is in the fortieth episode.

Soular knight of integrity

The soular knight of integrity is one of Alphys's six soular knights, more specifically the one that has a integrity soul in themself.

In the current published material, they are the fourth soular knight Frisk fights, and the third one she beats. However, they do not introduce Frisk to the way the integrity soul works, since she already got introduced by Papyrus. Their first appearance is in the fortieth episode.

Soular knight of justice

The soular knight of justice is one of Alphys's six soular knights, more specifically the one that has a justice soul in themself.

In the current published material, they are the last soular knight Frisk fights, and the last one she beats, and introduces to her the way the justice soul works, just before she fights Mettaton with it. Their first appearance is in the fortieth episode.

Soular knight of kindness

The soular knight of kindness is one of Alphys's six soular knights, more specifically the one that has a kindness soul in themself. They are also the one that is used to abduct people in the CORE and send them in the Oblivion prison.

In the current published material, Frisk meets them in the CORE, and gets beaten by them easily, just before being sent in the Oblivion prison. The are so the first soular knight Frisk fights, though they are the fifth one she has to beat. Thanks to Phobos's items, she eventually beats them. Their first appearance is in the thirty-ninth episode.

Soular knight of patience

The soular knight of patience is one of Alphys's six soular knights, more specifically the one that has a patience soul in themself.

In the current published material, they are the second soular knight Frisk fights, and the first one she beats, and introduces to her the way the patience soul works. Their first appearance is in the fortieth episode.

Soular knight of perseverance

The soular knight of perseverance is one of Alphys's six soular knights, more specifically the one that has a perseverance soul in themself.

In the current published material, they are the fifth soular knight Frisk fights, and the fourth one she beats, and introduces to her the way the perseverance soul works. Their first appearance is in the fortieth episode.


Syno!Sans is the Sans from an AU called Beforetale. It is stated that he got determination into himself and who got kicked out of his own universe. He lives in another universe, though which one is stated to be unknown by the protectors. He is stated to have fought in the Multiversal Sans tournament, beaten by Alpha!Sans in it.

Though he is incredibly secretive, even to the protectors, Syno!Sans mostly acts like Sans would normally do, laughing, making puns. Like Sans, he is very analytic.

He appears in Xénotale: Celerity, in which he is introduced during the Outertale meeting. He tries to help during the meeting, though he doesn't succeed like every other person in it. He reappears in the Doodle Sphere, hearing The Voice. Him and The Voice share the control of his body and words. He helps The Voice sending their message by lack of choice and begs to be authorized to leave the protectors. He eventually leaves, never to be seen again in Xénotale.

The Voice

Main article: The Voice

The Voice is the entity that follows and speaks to all beings who control the power of determination (in the order Chara, Flowey, Alphys, Flowey again and finally Frisk). They were created by Zeno and are under his command. They gave Frisk power, but she lost consciousness. The Voice criticizes Frisk every time she decides to scare or kill a monster in the neutral route. They are also a herald for Zeno's minions because they tell them his orders. They are most likely impossible to kill.

Because of that, The Voice has no real personality. Their name is "The Voice" because they're just a voice, and they don't have a material form.

In the current published material, after giving power to Frisk, they help Frisk to understand how the underground work and give her the solution to some puzzles. They also say to Chara that they have a work that is "exhausting" and "exasperating". Within the Snowdin Arc, they show to Frisk and Chara that they have a lot of knowledge about the Underground. They explain to frisk what a dimensional box is, then advise her sometimes. They explain to Frisk and Chara what the Loading Screen is while they are in it, and, during the revenge against the armored guard, they tell Frisk to act like if she was surprised of some events she knew about. When Zeno is talking to Frisk, they don't say anything. They incite Frisk to go behind the Waterfall she finds weird. At one point, she tells Frisk and Chara the story about Gaster not only the first time the texts about it appear, but also the second time. After her fight against mad Dummy, they tell Frisk where she should go. The second time Zeno appears, they don't talk and apologizes about it again. Their first appearance is in the first episode.

They make a brief appearance in Xénotale: Celerity, where they make the Multiverse panic by talking with or controlling beings with determination, which make them become an enemy of the protectors. This event is stated by Zeno to be a diversion though.

In Xéno!Papyrus's journey, they control Papyrus to makes him use the "escape" possibility, then disappear. Opposite reveals that The Voice attacks people who have determination in the Multiverse. Not long afterwards, Papyrus tells Ink!Sans and Opposite!Sans what he knows about The Voice. In Zeno's HQ, Papyrus learns that The Voice is a member of Zeno's organization. Some time later, The Voice helps Papyrus to succeed in his mission.

In Xéno!Frisk's arrival, they just slightly help Xéno!Frisk.

Trevor Kingsman

Trevor Kingsman is a human from the Corrupted Justice AU, and that lives in Seventon Hills.

He is a manipulative, spoiled and greedy individual with a lack of empathy, who is the son of one of Seventon Hills's richest families, and heir to their fortune.

In Xénotale: Celerity, he meets Celerity!Sans, and tries to make money out of his existence, as well as make him his body guard, by manipulating him. However, Celeirty sees through his intents, kills him and takes him deceit soul.

Ultimate Timeline!Gaster

Ultimate Timeline!Gaster is a character that appears in only one episode and is the Gaster from Zeno's origin AU. He is the royal scientist of the monsters of this AU.

He appears in Xénotale: Celerity where he shows that he is Zeno's soulkeeper. He gives Zeno his soul, which Zeno uses to create the soul of celerity. He doesn't reappear afterwards.

Underfell Flowey

Underfell Flowey, mostly known as Fell!Flowey by the Out!Codes, is a flower who lives in Underfell, an AU where it is killed or be killed, and watching what happens there.

Though he is pretty fearful, he knows how to recognize when there isn't any threat to his life, often watching what happens in the Underground while trying to not be located by anyone. He is curious and intelligent, being able to recognize who is new in a team just by looking at the team. However, he doesn't know anything about the Multiverse.

In Xéno!Papyrus's journey, he watched XGaster killing his Undyne, then started to watch her melt. He saw Ink!Sans and Opposite!Sans arrive, question her then being abducted. Not long after the abduction, he talks with Papyrus about it and about what he knows, but Papyrus kills him when he doesn't need him anymore.

Underfell Papyrus

Underfell Papyrus, mostly known as Fell!Papyrus by the Out!Codes, is a monster living in the Snowdin town of Underfell, often being seen with his brother Sans, though the latter tries to avoid him most of the time.

Fell!Papyrus refuses to admit it most of the time, but he cares about his brother Sans, and wants to avenge his death at all costs. He is not patient and hates all kinds of jokes. He is extremely bilious, killing if someone doesn't do what he wants.

In Xéno!Papyrus's journey, when Ink!Sans and Opposite!Sans look for Fell!Sans, they see Fell!Papyrus and question him about it. Fell!Papyrus tells them Fell!Sans is dead.

Underfell Sans

Underfell Sans, mostly known as Fell!Sans by the Out!Codes, is a monster who lives in the Snowdin town of Underfell, often being seen with his brother Fell!Papyrus, even if he tries to avoid him most of the time. Though he measures others' LOVE, he himself has a LOVE higher than 1.

He hates his brother, and often follows the motto of "It's killed or be killed.", though he is alone most of the time. He fights anybody without hesitation, unless this person has done an action notable enough to make him spare the person once. He hates his Flowey, but even killing him is not enough to make him spare someone. He doesn't hesitate to attack in a perfidous way, and is often arrogant. Sometimes, he underestimates his opponents.

In Xéno!Papyrus's journey, he sees Papyrus killing his Flowey then calls for Papyrus. He tries to kill him in a perfidous way but fails. They then fight each-other, which ends up in Papyrus killing Fell!Sans, the former trying to kill monsters to heal himself.

Underfell Undyne

Underfell Undyne, mostly known as Fell!Undyne by the Out!Codes, is a monster living in the Waterfall of Underfell.

In Xéno!Papyrus's journey, she was attacked by XGaster, the fight ending by XGaster leaving her while she was melting. She meets Ink!Sans, Opposite!Sans and Papyrus, then tells them about her fight with XGaster.

Underswap Asgore

Underswap Asgore, mostly known as Swap!Asgore by the Out!Codes, is a monster who lives near of the door between the ruins and Snowdin, and who often talks with Papyrus thanks to it.

Underswap Asgore is very kind with others, except for those who impersonate others. He likes honesty, singing and hates fights, though he knows how to defend himself. He often says "Howdy." to salute, and would be very happy if he could meet his Papyrus face-to-face. He knows that he needs to retire if necessary, and, like most of the inhabitants of the AUs, he doesn't know about the existence of the Multiverse and has a hard time understanding it.

In Xéno!Papyrus's journey, he meets Papyrus when he is in Underswap. Papyrus confused him with Der Schlächter during a short amount of time, then they both present themselves to each-other. He ends up thinking Papyrus is someone who impersonates his Papyrus. When Opposite arrives and when Opposite takes an attack to protect him, he retires. After that, he tells Ink!Sans what happened.

Undertale Frisk

Undertale Frisk, mostly known as Classic!Frisk by the Out!Codes, is the eighth human, without a determined sex, to fall in the Underground in Undertale, often used as a point of reference to know at what moment in the timeline they are in. Like all of the other inhabitants of Undertale, the Out!Codes prefer to avoid them, except for Error!Sans when he wants to protect Undertale from the Out!Codes who are in it.

Depending on the timeline the human is in, their personality can vary each time. In the eidocide timelines, the human kills the monsters for their own pleasure, doesn't show any form of empathy towards them, and has a violent behavior. However, Frisk seems to be curious in every case, since when they see things that are unknown to them, they wants to know what they are. They never abandon, even if they are near of the death.

Frisk is a human child who wears a blue shirt with pinkish purple colored stripes, blue pants, and brown shoes. They have medium-length straight brown hair, short and choppy bangs, and a blank expression most of the time.

In Xéno!Papyrus's journey, Papyrus's trial is to kill a variation of Frisk who has finished hundreds of eidocides, and who has killed Sans in one of them. Though, this one could easily kill Papyrus in one attack. However, he succeeds in killing it, which guarantees him to enter in Zeno's organization. Some Out!Codes outside of this organization have heard of it, like Alpha!Sans and Ink!Sans

Undertale Monster Kid

Undertale Monster Kid, mostly known as Classic!Monster Kid by the Out!Codes, is a monster who lives in the Snowdin town of Undertale, fervent admirer of the royal guard.

He is a great admirer of the royal guard, and even more of Undyne, often looking at Classic!Papyrus when the latter tries to enter in the royal guard, and being very jealous of him because he is a friend of Undyne. He likes to interact with others, and has a childish behavior.

Monster Kid is a yellow, reptilian monster with no arms, a tail, and spikes on the back of their head. He has markings under his eyes, one being bigger than the other, which could be black eyes from falling. They wear a yellow shirt with brown stripes.

In Xéno!Papyrus's journey, he makes a brief appearance. During this one, he talks with his Papyrus about his idea of entering in the royal guard, while Ink!Sans and Papyrus are watching them.

Undertale Papyrus

Undertale Papyrus, mostly known as Classic!Papyrus by the Out!Codes, is a monster who lives in the Snowdin town of Undertale, great friend of Undyne, who tries to enter in the royal guard. He is often seen by most people with his brother Sans, or taking care of his puzzles.

Though he is self-centered, he is extremely kind, couldn't kill anyone even if he should do it, and is full of energy. He likes to be a friend of every person he meets, as well as liking as much to see other persons becoming friends, even if he tries to force it sometimes. Though he blames him for his bad puns and his laziness, he loves his brother Sans, and likes to make jokes himself, if they are good ones. He is also an imbecile.

Papyrus is a tall skeleton. He smiles most of the time and his eyes do not have pupils. He also wears an outfit he made himself, which he calls his "battle body", which consists of a white chest plate with gold trim, coquelicot gloves with a golden trim, blue briefs with a golden belt, and knee-high coquelicot boots.

In Xéno!Papyrus's journey, he appears for the first time talking with Classic!Monster Kid, while Ink!Sans and Papyrus watch him. When he needs to leave Classic!Monster Kid, Ink!Sans and Papyrus need to leave Undertale. Later, he meets Ink!Sans, Opposite!Sans and Papyrus, the latter interrogating him. He ends up discovering the existence of the Multiverse, but has a very hard time understanding what happens. When Ink!Sans, Opposite!Sans and Papyrus fight Error!Sans, he tries to end this in a pacifist way, but Error!Sans uses him as a projectile. After that, Error!Sans decides to control him, but he ends up being freed and leaves afterwards. He reappears talking with his brother about his sudden disappearance, then he worries about his brother's health because he doesn't do any bad pun.

Undertale Sans

Undertale Sans, mostly known as Classic!Sans by the Out!Codes, is a monster who inhabits in the Snowdin town of Undertale, and judges people in Undertale. He has a sentry post with his brother, and is often seen with him.

Classic!Sans shows himself as a lazy monster to his brother, though he works a lot. He also shows himself as liking bad puns and doing a lot of them. However, when it is necessary, he becomes very serious. He loves his brother more than anything else, though he values keeping his promises above anything else.

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 slippers. He has white pupils that disappear when he is serious. Sometimes, when he uses magic, his left eye glows in cyan and yellow, and his right pupil disappears.

In Xéno!Papyrus's journey, Ink!Sans, Opposite!Sans and Papyrus ask him for help. After being told the Multiverse exists, he accepts. Like his brother, Error!Sans ends up controlling him, and he is freed as well. After Ink!Sans organizes a strategic withdrawal in Undertale, Opposite!Sans and Papyrus bring him in a discreet place and let him there. Later, he talks with his brother, then Ink!Sans calls for him, trying to find back Opposite!Sans and Papyrus. However, he doesn't know where they are. Undertale Sans reappears when Ink!Sans, with Papyrus, try to free Opposite!Sans. He fights Papyrus with Ink!Sans because Papyrus has a LOVE of 20. Classic!Sans ends up being trapped by Papyrus and dies.

Undertale Snowdin Innkeeper

Undertale Snowdin Innkeeper, mostly known as Classic!Snowdin Innkeeper by the Out!Codes, is the keeper of the inn of the Snowdin town of Undertale.

She likes to remark on what others' wear, doesn't like outfits that seem too serious because she thinks they are inappropriate. Howevr, regardless of this, she tries to keep her business as well as possible, though if a person doesn't spend much time sleeping, she repays the person. She is extremely polite.

In Xéno!Papyrus's journey, to rest after a misfortune, Opposite!Sans and Papyrus go to her inn. After a short discussion, in which she confused Papyrus with her Papyrus, Papyrus pay for the two and then they sleep. When they come back to her, she says a polite sentence, then after their departure, they never see her again.


XGaster is a Gaster who originates ffrom the universe known with the name of X-tale, and a destroyer of the AUs, allied with Error!Sans, which destroys the AUs because they are mediocre according to him. Unlike Error, he plans to destroy Undertale. He is an old friend of Ink!Sans, which has saved the Multiverse by destroying a part of his soul.

XGaster is extremely intelligent, but is also sadistic and manipulative, having made his own AU an experiment. He hates every other universe because they are mediocre, as well as Ink!Sans, who prevented him from continuing his plan. He is extremely confident in his knowledge, and doesn't hesitate to ally himself with other destroyers if necessary. He stays mysterious for most, and what his intentions were in Underfell are still unknown.

In Xéno!Papyrus's journey, he appears only in Underfell, fighting Fell!Undyne first to make her melt. Later, he abducts Opposite!Sans and Ink!Sans then released them under the condition that they leave, saying that he will destroy Underfell. After they left, Error!Sans comes to make sure he doesn't destroy Underfell. Ink!Sans, Opposite!Sans and Papyrus meet him again way later with Error!Sans thanks to Classic!Sans. Him and Error!Sans fight them, helped by The Voice. After the strategic withdrawal, Error asks him to leave, which he does. When he comes back, Ink has already left, and he himself leaves to destroy other universes.

He makes a slight first appearance in Xéno!Frisk's arrival, where he studies Cross!Sans and Cross!Chara's new fighting capabilities. He also teams up with Error!Sans and Xéno!Frisk to destroy Underswap, though he fails and ceases teaming with Error!Sans.

Zeno Dreemurr

Main article: Zeno Dreemurr

Zeno is the entity who beaten Undyne very easily in the past, as well as the creator of Xénotale and of The Voice. Frisk meets him at Snowdin when he beats Papyrus. He also blocks the exit of Waterfall as long as Undyne has not been beaten. He is there to help Frisk as a neutral or pacifist final boss. In eidocide, he makes Monster Kid stronger, trains Sans and gives the God's Help to Asgore. He is also the final boss in the eidocide route and has 5 phases in his fight, though, as the strongest being in the AU, he is impossible to beat.

In his normal form, he wears a black sweater with one red stripe. He has a golden hair that hides his left eye. His right eye is red and his left eye is a hole. Under his true form, he wears a green sweater with one yellow stripe. His hair and eyes are red and he has goat ears. He wears a broken locket made by himself with a part of his own soul.

In the current published material, he saves Frisk from Papyrus by ejecting him with a hand he created. He tells Frisk, Chara, and The Voice he knows everything about what happens and explains what he will do in the near future. He reappears as an enemy when Frisk and Undyne are about to fight. When Undyne attack him, he defends himself, then he shuts them in walls that disappear when one of them is defeated. His first appearance is in the first episode.[3]

In Xéno!Papyrus's journey, he asks Celerity to bring Papyrus to him. Later, when they all are in his HQ, he is presented to Papyrus as the boss of the organization. Papyrus doesn't want to obey to a child though. After an attack and some answers, Papyrus ends up accepting. Later, Zeno gives the mission of separating Ink!Sans and Opposite!Sans to Papyrus. When the mission is finally finished, he tells Papyrus he succeeded and reveals to Celerity who will be his next recruit.


Undertale Locations


Main article: Ruins

The ruins are the same as the original Undertale game except the Golden Flowers that have been replaced by black flowers. Toriel's clue on the right switch at the beginning is much more stealthy. The reluctant grey rock in the room where are three grey rocks is hidden to Frisk. The signs aren't here for the last puzzle.


Main article: Snowdin

In Snowdin, the geography is the same but the place contains Papyrus statues.. In the Snowdin forest, Papyrus's traps are deadly. In the Snowdin village, there is a central place for executions, as well as a Papyrus statue that hides the basements of the Underground.


Because of what the royal guards have done to get the territory, it lacks some places and some objects, such as the telescopes. All of the echo flowers are not there anymore, like the light in the place just before the Temmie village. There also is a door behind the waterfall Frisk goes through at the beginning. the golden flower bed is replaced by a black flower bed.
It isn't inhabited, due to being a battlefield for royal guards, with the exception of the Temmie village. It also does not have the echo flowers, since the royal guards have removed them all. It contains fragments of Gaster's story as well.

Temmie village

The Temmie village is a village known to be almost impossible to find, where the Temmies inhabit. The royal guards go in the Temmie village to get the control of it and to use it as a base for their operations.


In Hotland, Alphys changes all of the traps to make them more deadly for Frisk and the monsters.
The CORE has one floor known as the Oblivion prison, and is known for the disappearances of the people that enter in it.

New home/Barrier

In New Home, Frisk never encounters monsters. Asgore's house is destroyed and the Golden Flowers have been replaced by black flowers.
In the Neutral Route, the barrier has been destroyed by Zeno.

Added Locations

Alpha World

Main article: Alpha World

This world can only be created by Papyrus and Zeno. This world is, like the Anti-World, a very restricted space we can exit only if the one who created it decides it. Everyone suffers constant damage in this world in any case. The Alpha World cannot last very long since it self-destroys. This world can kill its occupants.


Main article: Anti-World

The Anti-world is a modified version of the universe created by Sans or Zeno during their respective battles. It's a location with a pretty restricted space and controlled by the one who created it. Only its creator decides if someone can escape it. In this world, its occupants constantly suffers damage unless if they stay in the attacks. The one who created this world is completely invincible in this one, however, he exhausts his magical reserves much more quickly, though Zeno who has an unlimited amount of magic. This world only appears during Sans and Zeno's fights in the eidocide route. This world reverses the colors of the normal world. If the creator of this world doesn't use other attacks, the world self-destroys. The opponent of the creator suffers 3 damage per second. Celerity!Sans can obviously create this world too.

Basements of the Underground

Main article: Basements of the Underground

In the Snowdin village, if Frisk enters in the giant Papyrus statue, she finds a ladder that allows her to descend into the basements of the Underground. Each part of this place corresponds to an Undertale location. To access these areas, except the basements of the Ruins and Snowdin, she has to find a key in the corresponding Undertale location. The basements of the Underground are where most of the dead monsters, turned into dust, are found. Frisk can also find some heal items like dog residues or false heal items like empty ketchup bottles or full ketchup bottles in this place. She can also find a room used as a torture chamber in these basements. This room is used by Papyrus in the neutral route to torture Sans if he's spared by Frisk.

Papyrus found this place by having the giant statue made to destroy the ground below this statue. He did hide this from all the monsters and only Frisk, Chara, Sans, Papyrus, The Voice, Celerity!Sans, and Zeno are aware of the existence of this place.

Loading screen

Main article: Loading screen

The Loading screen is the place where Frisk is after a death, and where she chooses if she continues, resets or quits. In this place, only the ones who have a certain amount of determination can survive. This place is accessible only by the ones who can use the full power of the determination, or by the ones who can create a portal or a spatiotemporal rift. Items aren't usable here. The Loading screen is also very dark, except at the place where Frisk have to choose between continue, reset anq quit. The characters keep their souls and all the soul types are usable here.

Oblivion prison

The Oblivion prison is one of the floors of the CORE, though it is not explicitly stated which one. It has been named like this because anyone who enters ends up being forgotten. The persons that are being imprisoned are the ones who enter the CORE, leading to legends saying it is impossible to escape the CORE. The Oblivion prison is led by Alphys, and guarded by the soular knights.

The Web

The Web is the spiders' operations, accessible only via invisible floor and made out of robust spider web, hence its name. It is the place Muffet and her spiders produce their food in all in secret, being away of Alphys's cameras. It was originally made to give the spiders a safe place to be.


The Void is the place where Gaster has been confined during many years. At a time, the place was empty but sometimes, tools appeared weirdly, which made Gaster able to build a teleporter. However, there has been a lot of testing. Many abandoned teleporters are there as well as tools. Sometimes, Gaster or Zeno work there.
The Void of the sixth eidocide timeline is where Zeno's organization throw their trash, and where Celerity and Zeno fought at the end of Xénotale: Celerity. There is a house in there that belongs to a Chara from a neutral timeline of the universe.

Zeno's HQ

Main article: Zeno's HQ

Zeno's HQ is a place located into Celerity!Sans's origin timeline. It's an eidocide Xénotale timeline where everyone (except Celerity and Zeno) died, including Frisk. This HQ is below the Last Corridor and can only be accessed by it. This is the main place where Zeno, Celerity!Sans and Zeno's other minions work. Nobody can enter without having Zeno's permission beforehand.

The headquarters contain a main room that is the room people are when they enter in the headquarters first, a dining room and an informative room, where all of the members of the organization reunite to have explanations on their missions or on situations. Since Xéno!Frisk is in the organization, they have a bathroom, though only Xéno!Frisk uses it. Each member of the organization has their own bedroom that can only be accessed by themself, by Zeno or by people that are authorized to enter by its owner. If someone is unauthorized to enter, the person can't see the bedroom. The owners of the bedroom can customize theirs.


  • When The Voice removes Frisk's mind, they add to her acts the scare act. This act allows Frisk to scare the monsters but they attack with all if their power. These attacks are called "scare attacks".
    • However, she can't use this power against some monsters, like Toriel, Doggo or Jerry.
  • Another act is added, the weapon switch act. If Frisk possesses more than one weapon, she can switch them during the fights. She can choose any weapon she got if she kept it.
  • When it is impossible to spare a monster, the spare option is replaced by "doing nothing".
  • In Xénotale, after the moment when Flowey recovered the determination, it was discovered that humans, as well as monsters who could bear it, could not exceed a certain amount of determination. In this case, the owners melt like the monsters. However, there are two exceptions to the rule:
    • Those who have many human souls can multiply the amount of determination that they can have by the number of human souls they have.
    • Zeno has an unlimited amount of determination.
  • The God's help is a help conferred by an unknown god that greatly increases the power of a human or a monster. This help is more effective than 7 human souls together.
  • The energy is an energy that can make only one entity stronger per timeline. In the eidocide route, The Energy appears in the second phase of Sans's fight, and because of that, he becomes stronger and stronger, though it only shows the full power of those who become stronger because with Celerity!Sans, who finished to become stronger because of that.
  • Unlike Undertale, people recover all their HP when their LOVE increase.
  • The toy knife is replaced by the fireproof knife. It is used to damage fiery enemies and to not take damage while attacking them.
  • The tough glove is replaced by the two boxing-gloves. These are used to attack twice in one turn.
    • The Voice has stated that the fireproof knife should be more powerful than them, though it isn't the case, and that why it is like that wasn't discovered yet.
  • The ballerine shoes are replaced by the fighting shoes. Those can be equiped while another weapon already is, and, after Frisk attacks with them, she can attack with the other weapon on the same turn.
  • The burnt pan is replaced by the dry wood pan. Though its main use is to deal more damage than the weapons Frisk got before, it also helps to fight electrified enemies such as Mettaton.
  • Frisk gets the real knife and the heart locket in the neutral route.
  • A new type of attacks, yellow attacks are added. Instead of using them to attack normally, those who use it attack while the yellow attacks create very little projectiles that take the shape these have to attack the opponent of their user.
  • Frisk can get keys during her journey in the Underground.
  • There are more than six humans souls existing in the Underground at the same time, discounting Frisk's.
  • Chara and Asriel's story is told by Zeno instead of being told by the monsters of New Home.


Part 1 - Ruins

Part 2 - Snowdin

Part 3 - Waterfall

The English translation stops here

Part 4 - Hotland

Part 5 - Oblivion prison

Partie 6 - Souls

The rest of the story cannot be told yet.

The rest of the story cannot be told yet.

The bonuses of Xénotale are stories that are extremely short telling the situations on the point of view of the monsters, these stories abandoning Frisk. It expands more on how the monsters acted to make the story go as it went.

  • The bonuses happen at specific moments in the story, and some other episodes should be read beforehand. These will be specified.

The rest of the story cannot be told yet.

The rest of the story cannot be told yet.



  • The Voice was inspired by Sky/The Virus from Freaktale.[4]
  • Frisk is LOVE 22 at the end of the eidocide route.[2]
  • Asriel has the equivalent of fourteen human souls during his fight in the pacifist route.[2]
  • In her Undying form, Undyne isn't more powerful than her Undertale counterpart.
  • One of Asgore's themes, Der Schlächter, means the killer in German.
  • The title of the sixth arc of the neutral route of Xénotale references a character from another AU.[5]
  • Like Undyne and Sans, Toriel, Papyrus, Monster Kid, Alphys, Gaster, Mettaton and Asgore have real fights during the eidocide route.
    • According to the author, the idea comes from Freaktale.[4]
  • Zeno comes from Undertale: The Ultimate Timeline, and his story was written in late 2017.
  • Xénotale was taken over when the author wanted to redo an AU because he loved Freaktale. However, it's when one of his friends announced she'll publish her AU that he published Xénotale.
  • The author of the AU created Celerity!Sans some weeks after having published Xénotale.
  • The name of the AU went from the greek word ξένος (xenos), which means strange.
  • The author hates when someone forgets the accent mark on the first "e" of Xénotale.