*Have you thought about a world where everything is exactly the same...
*Except you don't exist?

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* Do you wanna have a bad time?

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* Care to elaborate?

You should seriously add more in the introduction, before any of the headings.

"Take care out there, Mirror. Although there are some pretty bad eggs out there, don't forget that there are people here who care about you, a lot."
– Chara

AssaultTale is an Concept Change AU of Undertale, created by DarkPugLord23. It is based around an idea of what would happen, if the Underground is at war with itself when Frisk falls.


The Underground is nothing but a battleground, used by two warring factions. On one side, a peaceful group of monsters, led by Queen Toriel, strive to protect every human that falls down. The other side are a battalion of monsters, led by the ruthless King Asgore, who are against humans, and want nothing more than to gain the 7 human souls, escape the Underground and kill them all.

Before the war began, King Asgore, Queen Toriel and their children, Asriel and Chara, lived a happy family's life, surrounded by many of their loyal subjects, and the Royal Scientist, W.D Gaster, along with his assistants Alphys and Sans, had been trying to find a way to break the Barrier. It was just like normal, in the Underground. Then came the day Chara was supposed to poison herself on buttercups, to help the monsters escape the Underground.

However, before she could, another human fell into the Underground.

This human, like Chara, was peaceful and they were friendly with every monster they met. But these acts of KINDNESS were ignored by most of the monsters, and they were brought before Asgore, where he slaughtered them right in front of his own wife.

Toriel was horrified at this act, and had demanded an answer from her husband. Asgore revealed that he had always hated humanity, and when Chara had fallen, he had wanted to slaughter her and take her SOUL, but was prevented from that, due to Asriel being the first to find her. If Asgore had found her first, Chara would've been dead before anyone else could find her.

To this day,  very few know the truth as to why Asgore hated humans so much. All that was known, was that when Asgore was young, he was raised to believe that humans were nothing but evil. It didn't help that the village he lived in, was utterly destroyed by humans who were terrified of Monsterkind's ability to absorb human SOULs.

Him, Toriel and Asriel were the only ones to escape with their lives. It was then Asgore initiated the Great War, unknowingly sealing Monsterkind's fate.

Because someone else had just died in her place, Chara saw that there was no need to kill herself. But Toriel wasn't happy at all. She took Chara and Asriel, and moved to the Ruins and Snowdin, where the citizens, who welcomed them with open arms, were much more pleasant.

Acting as Queen, she peacefully ruled over The Ruins and Snowdin, and stated that any human who fell into the Underground, was to be treated with kindness. 

Asgore believed Toriel was being selfish about the first human's death, since the only chance Monsterkind had of escaping the Underground, required harvesting human SOULs.

6 months went past, and Asgore, in his rage, declared war not only on humanity, but on his wife too. Since Toriel refused to see things from his point of view, Asgore cut off all ties with his now-former wife.

He instated the law, 'Kill or be Killed' over the sections of the Underground he ruled over, which were Waterfall, Hotland and the Core. Any monster that refused to comply was executed.

At the Ruins, Toriel had heard a knocking on the Big Door, and was surprised to see a 17 year old Sans, holding a sleeping 5 year old Papyrus and at the same time, dealing with a wound in his left eye. She took the boys in, and nursed Sans' injury, where she was horrrifed to know that Gaster had been experimenting on DETERMINATION and monster souls. The experiments entailed a group of monsters, Sans and Papyrus' mother included, receiving shots of DETERMINATION, to see if any of them could manage to break the Barrier, somehow.

The experiments failed, and everyone who took part began melting together into Amalgamates. She was also shocked to know that the reason Sans had gained his injury, was because he was subjected to an injection of genetically altered DETERMINATION, through his eye. Gaster told him it was for the greater good, but Sans knew that everything he had told them, were lies. So he took Papyrus and, with the help of Alphys, did the only thing he could at the time; run.

Fast forward 4 years, Sans, now with his own place, takes care of Papyus and is often helped by Toriel, Asriel, Chara and the residents of Snowdin. 4 more humans fell, and all of them traversed through the Underground, only to be killed at the hands of Asgore, Undyne or Gaster. But it was at this point in time, where everything became what it had become now.

Another human had fallen, but this one was discovered by a 9 year old Papyrus, who was rather oblivious to the term, "Kill or be killed." Papyrus thought there was good in everyone, so, being the naive child he was, he accompanied the human to Asgore's Castle, hoping to change the King's mind.

Alas, it was not to be, because when they did try to get to the Castle, they were intercepted by Undyne. Papyrus valiently strived to protect the human, but instead, he was executed by the Captain of the Royal Guard for "Being a traitor to Monsterkind", and his dust was scattered among a few roses that were nearby. The human was taken to Asgore's Castle, where he shared the same fate as the humans before him.

Sans, wondering where his little brother had disappeared to, later discovered the rainbow scarf that Papyrus loved to wear, sitting next to a pile of dust and was distraught to know that his brother was dead. The news soon spread around the Underground, and the factions were made.

The Ruins and Snowdin were full of Monsters that wanted to help humans, while the Monsters that resided in Waterfall, Hotland and the Core thought otherwise. Some Monsters, like the Temmies, Napstablook, Monster Kid, and Alphys (along with Mettaton) immediately moved to Snowdin, either to escape the hostile areas, or offer their services to Queen Toriel. Other Monsters, like Undyne, who felt betrayed by Alphys, joined the ranks of Asgore.

Sans, Chara and Asriel work as sentries in Snowdin, making sure that the residents aren't attacked by Asgore's forces, while at the same time, they watch out for any humans that fall underground. The three live together in Sans' house, the three acting as a bunch of siblings.

It is a month, to the date, of Papyrus' death, that the Eighth Human falls into the Underground, and the Story of AssultTale begins...


There are three major divergent paths in the game's ending, depending on how the player resolves encounters with monsters: the Neutral run, the Pacifist run, and the Genocide run.


A human child falls into the Underground and encounters Flowey, a sentient rose flower who teaches them how to fight and spare a monster, but warns them that some monsters cannot be befriended. When Flowey is just about to ask the human a question, he is then interrupted by Toriel, a motherly goat-like monster. He disappears before she can spot him.

Toriel teaches the human to solve puzzles and survive conflict in the Underground without killing, unknowingly continuing Flowey's lesson. She intends to adopt the human, wanting to protect them from Asgore Dreemurr, the evil overlord of the Underground.

She tells them of the war currently happening in the Underground, between two factions, the Guardians (she tells them that her son came up with the name), led by her, Queen Toriel, who had sworn to defend all humans from the OOD (Order of Desolation), spearheaded by Overlord Asgore, who would stop at nothing to ensure humanity's destruction.

The human eventually leaves Toriel to search for Asgore's castle, which contains the path (blocked by the barrier) leading to the surface world.

As the human is about to exit the Ruins, they once again encounter Flowey, who apologises for leaving so soon. He congratulates the human on befriending Toriel and the monsters in the ruins. He gives them another warning, to take care after Snowdin, before disappearing underground again.

Once the human leaves the Ruins, they meet Sans the Skeleton and Chara, and the latter's brother, Asriel Dreemur. They show the human around Snowdin, with Asriel trying many times to capture the human, only to fail hilariously. He eventually gives up, and is not seen again until his battle at the end of Snowdin.

In Snowdin, the human meets characters such as: Alphys, the shy and timid scientist, who has a crazy obsession with anime and sushi, Mettaton, the flamboyant and narcissistic robot, who was under the impression that he was a super-star, despite him being made for protecting the queen, and Temmie, known to the residents of Snowdin as the Underground's second-worst swindler (named so, since every thing she sells is very expensive).

After sparing Asriel from his fight, the human moves on, only to meet Sans and Chara again, who treat the human to brunch at Grillby's. There, they mention Flowey, who apparently been giving Asriel cryptic messages about future events. They also warn the human that from this point on, the monsters will be very hostile. Sans notes that he can't help the human, since the Underground is currently in a two-day ceasefire, and any monster invading the other's territory will result in the ceasefire ending.

They part with the human, who goes through to Waterfall, and encounter Undyne, who chases them throughout the whole area. She had several chances to kill the human, but she is interrupted every time by a mysterious attack consisting of blue pellets.

She eventually corners the human at the entrance to Hotland, and fights them, but they escape, with Undyne in hot pursuit. However, soon after entering Hotland, she falls unconscious due to the heat. The human gives mercy to her, in the form of pouring water onto Undyne. She stands up, looks at the human for a minute, before retreating back to Waterfall.

Later, she calls the human, having received the number from Asriel, stating that she wanted to be friends. The human answers her request, and learns that Undyne had never wanted to kill humans, it simply was her job. Undyne tells the human that she had done something terrible in the past. She killed an innocent monster, and to this day she still feels bad about it. She didn't even know their name.

She is then befriended via cooking lesson, which sets her house on fire. After this event Undyne tells the human that because they had helped her, she has decided to help them by switching sides, and says she'll try her best to convert other monsters too.

Returning to Hotland, the human then enters a lab, belonging to Dr Gaster, who immediately initiates a fight with them. Gaster tells them that he will gratefully use their body as a cadaver to experiment on. After multiple failed attempts to spare Gaster, the human is forced to flee the lab, Gaster saying they'll meet again soon.

Soon, the human receives a call from Chara, who tells them to meet at the abandoned hotel, telling them she needs a chat with them.

Along the way, the human meets more monsters, and some of them are fought, with the human having to choose whether to kill them or to show mercy; should the human spare them, the monsters decide to leave them alone.

They meet up with Chara at the hotel, and she then tells them the story of how she came to the Underground in the first place, and why the Underground became the way it was today.

She gives the human one final message, before departing. The human makes their way through the core, and enters a fight with Muffet, who says that her spider friends are hungry, and the human would serve as a meal.

If spared, she walks away, saying Snowdin is much better for her business ventures. The human then reaches Asgore's castle. During their trek through the castle halls, the human learns the details and the cause of the war between humans and monsters, as well as the backstory of Asgore, and the reason he hated humanity so much.

The human soon learns that they also need a monster's soul to cross the barrier, meaning they have to kill a monster. Sans stops the human before their confrontation, revealing that the human's "LOVE" is an acronym for "Level Of ViolencE" and "EXP" for "EXecution Points." Sans judges the human based on the combined resolution of the encounters. He also states that he is the Judge of the Underground, and while he may be on the side of humans, he still has a job to do, no matter what. Depending on the human's actions, he will wish them luck before he disappears.

Then, they finally meet Asgore, who, despite hating humans, allows them to take whatever precautions they need before the battle. After doing what he asked, they fight and defeats Asgore. The human is then given a choice, to either spare him, or kill him.

If spared, Asgore will at first be surprised, thinking humans had no concept of the word MERCY. He declares the war over, and decides to make amends.

However, Gaster, who sneaked in during the battle, kills Asgore, steals the human souls, and becomes a monstrous abomination.

By calling out to the six souls for help, the human defeats Gaster, falls unconscious, and awakens on the human side of the barrier; they receive a phone call from Sans, explaining the state of the Underground after the human's departure.

Despite the disappearance of the human SOULs and Asgore's death, Queen Toriel, who now rules over the entire Underground, rouses the spirits of the Underground's inhabitants and tells them not to give in to despair. Sans likewise encourages the protagonist never to give up. He then tells the human that Gaster has not been found, and the Underground is on a manhunt for him, since they found out about his experiments.

Chara joins in the call, and says that the Underground is back to what it used to be: united as one. Now that everyone's not trying to kill each other, they can mend relationships between severed families they can work on rebuilding their home to it's former glory. She goes on to say that her statement sounded pretty corny to her, to which Sans agrees.

The call passes to Asriel, who proudly proclaims his new position as "CAPTAIN OF THE ROYAL GUARD." This turns out to be a figurehead position, as the Guardians have in fact been disbanded, since there is no war, and no need for factions. His only real duty is tending to the garden of the New Home castle, which he thinks is boring. Chara tells Asriel he also gets to bake cookies for everyone, and the latter exclaims in joy.

The former Royal Guard captain Undyne then enters the call and explains that she has found new work as Alphys's lab assistant. She has also been appointed to be the gym teacher of Toriel's new school; she boasts that she can bench-press seven children.

Alphys feels very awkward around her, and becomes rather reclusive. However, Undyne confidently states that she can help Alphys work through whatever is bothering her, and try and fix their relationship. Undyne also reminds the protagonist that she and the other monsters sacrificed a great deal to help the protagonist return to the human world; for that reason, the protagonist should appreciate life on the Surface to the fullest and make that sacrifice worthwhile.

Alphys is presumably nearby, and doesn't seem to want to talk to the protagonist, however, Undyne ropes her into the call anyway. Alphys first reassures the protagonist that Mettaton is doing okay, and then goes on to mention that she is searching for a new way to free the inhabitants of the Underground. She is working harder than ever, mostly because Toriel is a much stricter supervisor than Asgore ever was.

At this point, it occurs to Undyne to ask Toriel to join the conversation; however, Toriel simply tells her that she is busy, not realizing that the protagonist is on the other end of the line. Chara and Sans joke that Toriel would probably tie up the line for hours if she only knew the protagonist was on the phone, and that they "have the mercy to spare you from her." Asriel doesn't agree, but keeps quiet anyway. Undyne and Alphys then suggest calling back anytime as she would love to talk.

The call ends with Sans mentioning that the phone is low on batteries, and everyone says goodbye, before he hangs up.

True Pacifist Ending

At the end of the Neutral Route, Flowey appears and asks the protagonist to unite the Underground as one, and to also give a hint as to the requirements for the True Pacifist Ending. The protagonist can then reset to the SAVE point before Asgore's fight to fulfill any missing requirements as long as they have not gained any EXP/LOVE.

After completing the required tasks, the protagonist will receive a phone call from a mysterious person, who asks them to come to Gaster's Lab in Hotland, where they will "meet their destiny."

Arriving at the lab, the protagonist finds an elevator inside. They take the elevator down to the True Lab, but it loses power and malfunctions, leaving them stuck in the lab. Exploring the lab, they find logs from long ago, detailing Gaster's experiments with SOULs and Determination to transform monsters into super-soldiers. Injecting determination into the monsters made his plans a success, but they melted and turned into Amalgamates - fusions of several monsters, one of which included his own wife.

Several of these amalgamates attack the protagonist, but the protagonist spares them. The protagonist sees the Determination Extractor, resembling part of Gaster's form during his boss battle in the Neutral Route, and they learn that Gaster did some experiments involving Determination, monster dust and roses, which produced a single living specimen who escaped.

The Protagonist also learns that Gaster is the father of Sans and a monster named Papyrus. Sans was subjected to cruel experiments that ended up making him the first monster to survive a successful Determination Infusion, and not melt. This is what led Sans to run away and end up in Snowdin.

The protagonist switches the power on, restoring power to the elevators. On their way back to the elevators, the protagonist is confronted by Gaster in front of the Determination Extractor. Gaster states he has a score to settle, and initiates a battle with the protagonist. During the battle, the player is given very little chances to heal, and cannot spare nor attack Gaster, since he too is an Amalgamate.

The protagonist is reduced to one HP, and Gaster prepares his strongest attack. Before he can unleash it however, one of the Amalgamates interrupts the battle, and pushes Gaster into the Determination Extractor. The machine is activated, and Gaster perishes, due to him consisting of nothing but Determination.

The Amalgamate turns to the protagonist, and it is revealed to be Gaster's wife/Sans' mother, fused with a Froggit, Goner Kid and a Knight Knight. The Amalgamate asks the protagonist to tell Sans "HE'S gone now. You are safe.", before it disappears into the darkness, presumably to rejoin the other Amalgamates.

The protagonist returns to one of the elevators. They receive a call from someone they do not recognize. The voice tells them that 'everything has fallen into place' and that they will 'see you soon.'

The elevator appears to malfunction and lands the protagonist at the entrance to New Home. White, thorny vines jam the elevator shut, forcing the player to move on.

At the barrier, the protagonist confronts Asgore one more. As they prepare to fight, Toriel arrives, incapacitates Asgore and consoles the protagonist. After reprimanding Asgore for his actions, even going as far as to smack him, she is shortly later followed by Sans, Chara, Asriel, Undyne and Alphys, who all begin to chat. To Alphys' surprise, Asriel reveals that a 'tiny flower' helped him call everybody to the Throne Room. Chara immediately says "Uh oh." after this.

Flowey arrives and traps the other monsters in vines. He then thanks the protagonist for bringing them all to one spot, saying that he absorbed the humans' SOULs while the protagonist's friends were chatting, claiming he will absorb them all as well to achieve his true motive - breaking the Barrier. Flowey says that in order for the Barrier to be broken, he needs everyone's SOULs, including the protagonist's. He also states that in order to get their SOUL, he needs them to die. Before delivering the final blow, the protagonist's friends protect them from Flowey's attacks while both healing and encouraging them to win.

Shortly afterward, many of the monsters that the protagonist spared throughout the game arrive, healing the protagonist and seemingly putting Flowey off guard. However, he suddenly laughs at them, states that he will always be the 'greatest,' and absorbs their SOULs.

The protagonist sees that Flowey is now a young skeleton monster in a red scarf and a striped shirt, similar in appearance to a normal human skeleton. He decides that he doesn't want to break the Barrier any more because if he did, he would turn back into a flower. Flowey thinks the protagonist is trying to stop him. He then transforms into an older, more powerful looking monster, introducing himself as The Great Papyrus.

Papyrus attacks the protagonist with reckless abandon; if the protagonist's HP reaches 0 and their SOUL breaks, instead of resetting to a previous SAVE point, the message "But it refused" appears and the SOUL reforms through determination and fully restores its health. After this happens once, the SOUL simply reforms and return to the battle.

After a certain amount of turns, Papyrus attacks with an attack he calls "Ultimate Super Awesome Special Attack.", which entails the protagonist having to dodge a volley of basket balls, multiple wavy strands resembling spaghetti and a barrage of bones, some of which spell out "Cool Dude." The protagonist's HP is left at one after this attack if they get hit. Surprised at the protagonist's high determination, Papyrus reveals that he was only using a fraction of his real power, and he can become even greater.

Papyrus then transforms into a much more powerful form of himself, which he calls "The Even Greater Papyrus." He threatens to reset the world's timeline, restraining the protagonist and preventing them from doing anything except struggling.

The protagonist realizes that while they cannot move or attack, they can save their friend's SOULs, transforming the ACT option into the SAVE option. They reach out to their friends' SOULs (who are trapped in Papyrus' SOUL) and bring them back by restoring their memories. After saving all their friends, the protagonist begins to save Papyrus himself and see memories of him as a young child, befriending one of the fallen humans.

The protagonist's friends' SOULs resonate within Papyrus; he begins to cry, and his bone attacks start avoiding the protagonist's SOUL. He then begs the protagonist to let him win and attacks them with his strongest attack. The protagonist survives with their HP reduced to one ten-billionth of one point, and then they finally save Papyrus, returning him to his form as a child.

Papyrus apologizes to the protagonist. He asks them for their real name, which is revealed to be "Frisk." Papyrus tells Frisk that everyone's SOULs allowed him to feel their emotions and desires - their love for Frisk and their desire for freedom, respectively. He expects Frisk not to forgive him for everything that happened, but they can choose to anyway, surprising Papyrus. Using the six humans' SOULs, Chara's SOUL and the monsters' SOULs along with their determination, Papyrus destroys the barrier.

Papyrus returns the SOULs and tells Frisk that without everyone's SOULs, he will eventually return to a flower, and he will no longer be the Great Papyrus. He asks them to forget about him and leaves, but Frisk has the option to console Papyrus, which allows Frisk to approach and hug him.

Frisk wakes up in the room behind the Throne Room, much to the relief of their friends, who all know Frisk's name but do not remember much about what just happened. Chara remarks that Frisk's name opens up a new world of puns Toriel and Sans agreeing. Toriel encourages Frisk to do as they wish, whether that be heading for the Surface or going for a walk Underground to see the rest of their friends. The monsters and Chara inform Frisk that they will follow Frisk to the surface when they are ready.

Frisk can go through the Underground and talk to the inhabitants of the Underground, including the several monsters encountered only during battle encounters. They express their feelings, often about being free at last.

Frisk and their friends watch the sunset on the surface. Thinking about the future, Asgore asks Frisk if they would act as the monsters' ambassador to the humans. Asgore will comment on their decision, criticising them if they decline, and praising them if they accept.

Asriel leaves to make a good first impression on the humans, having declared himself the mascot or ambassador depending on Frisk's decision. Sans retreats to the Underground (presumably through a shortcut) to ensure he does not have to check on Asriel, while Undyne, Alphys, and Asgore, the latter saying he will learn to tolerate humans, leave to help Asriel.

With everybody else gone, Toriel and Chara ask Frisk what they will do now. The protagonist can choose to stay with Toriel or not. If they choose to leave, Chara will be annoyed with Frisk's decision and leaves. If they choose to stay with Toriel, Chara will welcome Frisk to the family, and says, "Hope you like chocolate, cookies and ketchup for breakfast!" before leaving.

After Toriel and Frisk leave a moment later, the True Pacifist Ending will be complete.

Genocide Route

The Genocide Route occurs when the protagonist kills every enemy in every region: the Ruins, Snowdin Forest, Waterfall, and Hotland.

If the protagonist stops meeting the requirements for a Genocide Route at any point, they revert to a Neutral Route. Monsters will still occur in the region of the Underground where the protagonist abandoned a Genocide Route, however, most monsters will be quite wary of them.

Starting in the Ruins, the protagonist intentionally triggers encounters and kills monsters until encounters with monsters no longer happen. After killing all monsters in an area, the protagonist will move on to engage Toriel, killing them with one hit. Toriel will look betrayed, and states "Now I see. It wasn't you I was protecting, but them. I should've listened to Asgore..." before fading to dust. Flowey doesn't appear after.

After exiting the Ruins, the protagonist will encounter Sans, who is a little disturbed that the human didn't react to their joke. He then attempts to hide them behind the conveniently shaped lamp, but they ignore him. Chara seems disappointed. Asriel runs in, and leaves after Sans tells him he found a human and doesn't notice the protagonist. Sans then tells the protagonist that they should continue pretending to be a human, before leaving.

The protagonist ignores all of Asriel's puzzles and traps, and some of them appear to be solved with some sort of help.

The 'Gauntlet of Ultimate Dread' is retracted after Asriel feels like the human would not appreciate it. After he leaves, Sans warns the protagonist that they will "have a bad time" if they continue the way they are currently going, specifically mentioning the protagonist's upcoming battle with Papyrus. He then seems to teleport out of the area. Chara says nothing, but they appear not to be smiling anymore.

Once the protagonist kills enough monsters, all Snowdin except Monster Kid evacuate and due to the absence of Temmie, whom they killed earlier, the protagonist can steal all of her wares from her shop. The protagonist enters Grillby's restaurant, and engages Grillby in a fight. They are able to kill him if they splash a nearby glass of water on him, due to Grillby being a fire creature.

Asriel tries to convince the protagonist to be a good person and immediately offers to spare them. The protagonist instead kills them, by slicing their midsection. Even after being killed, Asriel still believes that the protagonist can do better. Sans and Chara are not seen again for a while after Asriel's death.

The protagonist continues onto Waterfall, and they immediately encounter Mettaton. He doesn't fight the protaganist, but instead gives them a warning. He also states that the two factions of the Underground have joined forces temporarily to kill the protagonist, but leaves quickly after, saying that he's "revealed too much."

The protagonist then proceeds to kill every monster in their path. They are unable to kill Monster Kid at first, though the protagonist does climb on their shoulders roughly.

Along the way, they encounter Mad Dummy. The protagonist's actions upset the Mad Dummy so much that it causes them to become corporeal, turning them into the Glad Dummy. Since the protagonist helped the Mad Dummy become corporeal, they immediately offer to spare them. They are killed instead. However, straight after, Napstablook, possessing a suit of armour, appears, having had enough of the protagonist's actions. But due to possessing a solid object, Napstablook unknowingly made himself vulnerable to the protagonist's attacks, and is killed too.

On the bridge near the end of Waterfall, Monster Kid approaches the protagonist, saying that Undyne told them the protagonist had done bad things and began to see the truth in her words. They try to fight the protagonist, but when the protagonist retaliates, Undyne jumps in and takes the fatal hit. This is the first time she is actually seen in Waterfall (all other encounters with her are just her spear attacks.)

Instead of dying, however, she recovers and becomes Undyne the Undying, who is significantly more difficult than the ordinary Undyne boss fight. After being defeated, Undyne dies with a smile, aware that Alphys is evacuating the monsters ahead of the protagonist, and will tell Asgore to absorb the souls he has collected. Her last words are an apology to Alphys.

Upon entering the lab, the protagonist encounters Gaster, who doesn't initiate a fight with them. Instead, he asks them to take a walk with him outside, for a friendly 'monster-to-monster' chat, indicating he does not see the protagonist as human. The protagonist and Gaster walk outside the lab, and stop at a cliff, overseeing a sea of lava.

Gaster goes into a small speech, stating that living underground tires him, and that he has a plan for escaping. He intends to sneak into the Throne Room when the Human and Asgore are distracted, then absorb the six human SOULs before leaving the Underground, hoping to wage war with humanity. He then asks the protagonist what they think.

However, the protagonist engages him in a fight, much to his confusion, and stabs their weapon into the floor, breaking the ground under Gaster's body. This causes him to fall into the lava, and melt to death.

The protagonist kills more monsters, including the Royal Guards, before making their way to Muffet's. Before she is fought, she does not consider the protagonist to be fit to eat but attempts to dispose of them regardless. The protagonist can kill her in a single attack.

Mettaton is encountered inside the abandoned hotel, and fights the protagonist, who tricks him into falling into the still-working water fountain, which causes him to short-circuit and explode.

In the Core, Alphys and Monster Kid, who now sports robot arms (similar to Mettaton NEO from Undertale) are encountered. In order to fight Alphys, the protagonist must kill Monster Kid first, otherwise, any attack made to Alphys will be deflected by him.

Once Monster Kid is out of the way, Alphys will be open to attack. However, after a certain amount of turns, she will reveal that she took a shot of Determination, before hitting the protagonist with a barrage of attacks. During this attack, she will succumb to the effects of Determination, and will start to melt. Once her attack stops, the protagonist can kill her. No more monsters are fought after her death, as the point of no return has been reached.

When entering New Home, Flowey appears, and chides the protagonist for "not playing nice." While walking through Asgore's Home, Flowey talks to the protagonist. He tells them his story, of what his life was like before he became a flower, and after.

Flowey reiterates Asgore's "Kill or be killed" mentality, saying that the protagonist shouldn't listen to every bad thing they hear. He disappears afterward.

In the Last Corridor, Sans does not judge the protagonist but instead warns them that they will have a bad time. He fights them as an attempt to stop them from destroying the timelines of all worlds. He fails, and is fatally wounded. He warns the protagonist that if they are adamant on continuing their genocide, then there is one more challenge after him. He also says that he should've seen this coming (referring to his death), and that if it happened to other Sanses, why should he be spared? He then walks off-screen, asking Asriel if he wanted anything from Grillby's. It is unknown if he dies or not.

Within the throne room, Asgore mentions he was right about humanity after all. When he notices the protagonist, like Gaster, he does not immediately recognise them as human, and asks what they are doing here. The protagonist then proceeds to attack Asgore, killing him in one hit. Flowey finishes Asgore off and asks the protagonist if they are alright. Flowey states that he saved them from Asgore, and is wondering why they haven't thanked him yet. However, he finally realizes, in horror, that the protagonist is going to kill him. With his face and voice turning to that of Papyrus', he begs the protagonist not to kill him.

After Flowey has been killed, the protagonist moves on to the Barrier, where they meet the final challenge Sans referred to, in the form of Chara.

Chara is facing the Barrier, and takes note of the protagonist's arrival. Chara states that she thinks the protagonist is being controlled by some otherworldly force, but quickly dismisses her statement.

The protagonist steps fowards, and Chara turns around. The SOUL canisters rise up from the ground, only to reveal that they are empty. Chara says "Yeah, these guys aren't too happy with what you've done, mirror." referring to the SOULs, and indicating that she has absorbed them.

The protagonist engages a fight with Chara. Her face morphs into a ghastly visage, and her eyes flash all of the colours of the SOULs, including her own. She uses a plethora of knife attacks, as well as bones, fireballs, Gaster Blasters, electric bolts, stars, pellets and spears, as well as the individual SOUL attacks. A ghostly image of a previous character will appear behind her, corresponding with a certain attack, for example: Sans for the bones and Gaster Blasters, Alphys for the bolts, Flowey for the pellets, Asriel for the stars, the SOULs for their individual attacks, etc.

After a final stand by Chara, using a combination of knifes, stars and Gaster Blasters, she is defeated. It is here, that Chara reveals her biggest secret; she is self-aware.

She tells the protagonist that she knows her world is a lie, and that nothing really exists. She acknowledges that she, the protagonist and the rest of the characters are "nothing but lines of code, trapped in an endless cycle of repeating their lives."

Chara also mentions that while Sans and Gaster do know of Alternate Universes, she is stuck with the knowledge that the world she lives in is just a game. She even goes as far to say "Everyone's lives are absolute hell, and they don't even know it."

She will recount the amount of times the protagonist has died in the Genocide Route, but no matter what the number, she will always say the same thing; "that's not nearly enough times."

The protagonist is drawn inside their mind, and are met with a dark version of themselves, known only as The Player. The Player thanks the protagonist for their help, but says their services are no longer required, and kills them.

Back in the world, The Player, now possessing the protagonist's body, confronts the dying Chara. They have a conversation with each other.

Chara asks what The Player had to gain for doing all they did. The Player responds simply with "Nothing much. It's just a game, after all." The Player walks toward her, intending to finish her off. However, they are prevented from doing so by the six human SOUL's, who each have 1 HP left.

Chara, using the last of her and the SOUL's powers, destroys the world and rebuilds it in a flash of white light.

The protagonist regains control of their body, and finds themselves back at the start, where they fell down to the Underground. They then hear a voice inside their head, that states "I always come back." suggesting that The Player may not be gone at all.

The screen goes black, and demonic laughter can be heard. Once the laughter finishes, the Genocide Ending will be complete.

Secret Ending

This ending can be unlocked if the Genocide Route is aborted during Alphys' fight. Omega Gaster's fight doesn't occur, since Gaster was killed in Hotland.

Sans phones the protagonist, and says he'll leave a message.

He says Alphys has become the ruler of the Underground and, due to the protagonist killing Undyne, she went crazy and enforced a policy to destroy all humans who enter. She plans to wage war on humanity, has militarized the Underground, and personally plans to destroy the protagonist.

He also says the humans SOULs were missing to, so "that plan ain't happening any time soon." Sans passes the call to Chara, who mentions not being able to find Toriel.

She says that the Underground itself has gone a little crazy, considering that all of the leaders of the regions are dead and that most of the population is dead. Chara also states that everyone that is still alive thinks that she was the one that killed them, due to their resemblance to the protagonist.

Chara says that "everyone is waiting at home for me. Everyone is waiting to hurt me." She leaves off, say that Sans will protect her, since he's all she's got now. Chara passes the phone back to Sans, who warns the protagonist to watch themselves as "things are lookin' real bad for you."

The phone hangs up, and a moment later, an attack sound is heard. An image shows the protagonist sitting against a rock outside the barrier, the phone off to their side. A knife with a blood spatter on it also sitting nearby indicates that the protagonist committed suicide after the call.

The link to the phone call script can be found here:



Frisk - Eighth Human to fall underground, and the Main Protagonist of AssaultTale. Has a VERY short temper, is quite sassy, and is not too fond of their human parents.

Toriel - The Queen of the Monsters, and leader of the Guardians. (Asriel made the title, and no-one had the heart to tell him no.) Her healing magic, combined with her extremely powerful fire attacks make her the third most powerful monster in the Underground

Sans - A sentry of Snowdin, and a very lazy, but very powerful Monster. Powerful enough to earn him the rank of fifth most powerful monster in the Underground. Still dealing with the loss of his brother. Remembers RESETS. Harbours a deep hatred for Gaster, for what he did to Sans and his mother. He is aware of AU's, as referenced by his dialogue during his fight in the Genocide Route. (NOTE: his fight is considerably easier than other Sanses.)
AssaultTale Sans (Coloured)

Chara - A sentry of Snowdin, and also very lazy. She was taught how to fight from Sans, and therefore, she takes after his personality. Also remembers RESETS. Due to her learning magic attacks, her SOUL was corrupted and wouldn't pass as human, so it can't be used to break the Barrier. Adopted daughter of Toriel. She is self-aware, meaning that she knows she's in a game.

Asriel - A sentry of Snowdin, and known by the locals (and Chara) as the local cinnamon roll. Hates puns, but loves puzzles, and thinks himself very high and mighty. Also thinks he has to protect Sans and Chara from everything. Unlike the former two, he doesn't remember RESETS. Owns a battle tank for some reason, given to him by Sans on his birthday, and he calls it his 'Special Attack'. 

Alphys - The Royal Scientist of Toriel, and a good friend of Sans. She is rather insane about Anime, and because she hasn't had any part in the Amagamations' creation, she isn't very nervouse whatsoever, although she does still lock herself in her room for days on end and binge-watches anime, quote, "Like a total loser!" Misses Undyne.

Mettaton - A literal 'ghost inside the machine', and the self-proclaimed 'Cheerleader', although his actual job is to guard the Queen. Can be very flamboyant and annoying at times, but when he is needed, he is a very good fighter, even with his way of showing it. Has no EX or NEO forms.

Napstablook - Very shy at times, but is really friendly. A resident of Snowdin.

Temmie - A shopkeeper in Snowdin. She is also known as the second biggest swindler in the Underground, after Muffet, of course.


Asgore - One of the main antagonists of AssaultTale, and King/Overlord of the Underground. After Toriel left him and took the children, he snapped and became a cruel/heartless dictator. Second most powerful monster in the Underground.

Gaster - The Royal Scientist of Asgore, and the most powerful monster in the Underground. Gaster is also the other main antagonist. He spends much of his time in the lab, working on ways to break the barrier. A living Amalgamate, so hitting him won't do any good. Seems to have some sort of ulterior motive. Like Sans, Gaster also knows of other universes.

Undyne - Captain of the Royal Guard, Second-In-Command to Asgore, and the second successful attempt of combining Monster SOULS with DETERMINATION. Fourth most powerful monster in the Underground, and responsible for the murder of Papyrus, unbeknownst to Sans. Misses Alphys but feels betrayed by her.

Muffet - Not really evil, just that her stock prices are so high, and she holds people at gunpoint until they buy something.


Flowey - A talking rose flower, and the re-incarnated form of Papyrus, Sans the Skeleton's younger brother. He is nice to the Protagonist at the beginning. Flowey seems to work for himself, as shown in the True Pacifist Ending, where he intended to break the Barrier using everyone's SOULs, but become corrupted by the power.

The Player - A mysterious character, who seems to be watching the protagonist's every move. They are presented as a shadowy form of the protagonist, with grey skin, white eyes and black hair and clothes. They are presumed to be antagonistic, as evidenced by their actions in the Ending to the Genocide Route.

Major Changes

  • Chara, Asriel and Gaster are still alive.
  • Toriel is still Queen, although she rules over 2 parts of the Underground.
  • Asgore, Undyne and Gaster are evil.
  • Gaster created the Amalgamates, not Alphys.
  • Asgore had always hated humanity.
  • Asriel and Papyrus switched places.
  • Alphys, Monster Kid and Grillby are able to be killed. (Genocide Route Only)
  • Chara not only remembers RESET's, but she is also aware of the Real World.



  • This AU shares some similarities to other AU's of Undertale.
    • For example, Chara and Asriel are sentries in Snowdin, and their personalities, and the way they are dressed is similar to Storyshift.
    • Asgore and Undyne's behaviour is similar to the way they act in Underfell. The same is said for the way they look.
      • The citizens/NPCs in Waterfall, Hotland and the Core also act similarly to their Underfell counterparts, while the NPCs of Snowdin and The Ruins act as they do in Undertale.
    • The way Gaster experimented on Sans is similar to Zarla's 'Handplates' comic, which can be found here:
  • The creator/author of this AU, DarkPugLord23 came up with the idea of AssaultTale, while making an art project. He had started with his own design of Sans, and the rest came to him gradually.
  • The Player, met only at the end of the Genocide Route, may be a reference to the actual player in real life.