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

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Slight Alteration is an AU of Undertale in which Chara convinces Asgore to go through the Barrier instead of Asriel, and so events and character placements change.


Slight Alteration begins when the first human, Chara, falls into the Underground and is adopted by the Dreemurr family. Chara grows strong bonds with everyone, but especially Asriel. The two inseparable siblings find themselves in trouble everywhere. But when the idea to use Chara's soul and travel through the Barrier occurs, Chara goes to her father, Asgore rather than go to Asriel.

Chara's decision was down to strength, as Asriel would not be strong enough to retrieve the six human souls needed to free the monsters. Asgore on the other hand was strongest of the monsters and her adopted father, and so fitted perfectly for her to try and convince. Also, Asriel was seen as cowardly in Chara's eyes. At first, Asgore refused the suggestion of using Chara's soul, but after spending time amongst his people and seeing the desperation in their faces, he accepted the idea.

Asgore absorbed Chara's soul and went through the Barrier and headed to the local human village. With his might and trident, Asgore killed six humans and took their souls, ready to turn around and head straight back to the Underground. But, taken by surprised, the humans fought back and mortally wounded the king. Just managing to make it back through the Barrier, Asgore died and Chara with him and the six souls he took lost, scattered around the Underground.

The monsters grieved the loss of their king and in his absence looked to Toriel as Queen with Asriel as heir. Asriel had become angry and bitter with the death of Asgore and Chara, upset that he was not the one to go believing himself to have been strong enough to succeed. While Toriel ruled the Underground with peace, Asriel grew impatient to rule and eventually overthrew his mother and banished her, she fleeing to the Ruins.

The younger, feistier and inpatient king ordered for every human to be killed and brought to him as soon as any would fall into the Underground. He also ordered a decree that every royal guardsman available, retired or not, should retake action to insure that any human would be captured. Asriel was bad-tempered and ruthless, often blaming and shouting at random monsters just to take out his rage. Most of the monsters despised their new king and the stricter rules and taxes he put upon them, but they complied.

Character Changes

  • Sans- Sans
  • Papyrus- Papyrus
  • Undyne- Undyne
  • Alphys- Gaster
  • Toriel- Toriel
  • Asgore- Asriel
  • Asriel- Asgore
  • Chara- Chara
  • Mettaton- Madaton (Mad Dummy)
  • Gaster- Alphys
  • Napstablook- Mettaton
  • Mad Dummy- Sad Dummy (Napstablook)
  • Gerson- River Person
  • Temmie- RG1 and RG2
  • RG1 and RG2- Gerson
  • Burgerpants- Temmie
  • River Person- Riverpants (Burgerpants)
  • Monster Kid- Monster Kid
  • Grillby- Grillby
  • Muffet- Muffet
  • So Sorry- So Sorry
  • Nice-Cream Guy- Nice-Cream Guy
  • Catty and Bratty- The Snowdrake Family
  • Snowdrake's Mom- Catty and Bratty
  • Aaron- Aaron
  • Shyren- Shyren and Shyra
  • Onionsan- Onionsan
  • Canine Unit- Canine Faction
  • Endogeny- Endogan (Canine Unit)


The first human to fall into the Underground, Chara was adopted in the same way as in the original Undertale. She became a member of the Dreemurr family and became close to Asriel. But the decision to use her soul and travel through the Barrier was not shared with Asriel, whom Chara thought too weak and scared for the task.


Asgore remained the same as in the original Undertale until he was brought Chara's plan to cross the Barrier. At first, his conscience would not allow such a plan until he decided for it after realising his people's despair and longing to be freed of the Underground. He than went with Chara's soul through the Barrier and managed to kill six humans and took their souls. However, he was struck down by the defending humans and only just managed to trudge back through the Barrier where both his soul and Chara's were shattered. But instead of dying, the flower bed on which he died on was tested on by Dr Gaster as part of the determination experiments and the once king of the monsters became Gorey, the sentient flower with the ability to reset and save. Themes: Your Best of Friends, You Imbecile!.


When Chara first joined the Dreemurr family, Asriel grew a strong bond with her and the pair shared everything the knew and owned. But when Chara chose Asgore rather than Asriel to help her cross the Barrier, Asriel grew angry and upset. The news of the King and his siblings death had enraged Asriel, becoming aggressive and violent. He eventually took over the throne, exiling his mother and issuing his laws and taxes upon the monsters. He began growing the Royal Guard substantially, preparing for his desired 'War of Revenge' against the humans on the surface. In short, he began a reign of tyranny.

To display his role as the warring king, Asriel always wears his suit of armor and carries his blades at either side of him. His face is scared, on his left cheek from a bullet grave and his right eye, cut down with a sword, and so blinded.


As King Asriel had demanded for as many Royal Guardsmen as possible to take action, Undyne had to accept Papyrus into the Royal Guard as Lieutenant. The Great Lieutenant Papyrus received all the things that he wanted by becoming Undyne's second in command. He became more popular than Undyne and even managed to open his own Spaghetti business. However, under all of his hopes and dreams come true Papyrus questioned the cause that he represented and the king he served. He had seen how the monsters saw their king and he had felt that the Underground lacked enough kindness. As a result, he endeavored to bring as much kindness as posable to make up for all of Asriel's ruthlessness. He also began training the Snowdin children to become as 'great' as he was. Themes: Nyeh Heh Heh!.


The Royal Scientist, W.D.Gaster, was heavily affected on hearing the news of King Asgore's death. So much so that to carry on with his studies he had to take on an assistant, Dr Alphys, to continue his work. On orders from the new king, Gaster was to create armors and weapons for a future war against the humans after the Barrier was to be destroyed. Reluctantly, he had to accept or else be convicted and so went about forming various forms of weapons, along with continuing his own studies. Themes: Dark, Darker, yet Light Still Shines.


Sans' stuggles with his knowledge of resets and his insignificance in shaping the future would have led him into depression if not for Gaster. Gaster shared his own knowledge of timelines and giving advice on how to deal with it. Because of this help, Sans never fell into depression and began to re-enjoy his life and his work. He became an active sentry, took responsibility for his quiches and began creating dozens of puzzles with his brother.


Gaster's influence on his friends and colleagues were strong, as he was known for his kindness and advice. For Alphys, Gaster managed to build up her courage and convince her to be honest. She even manages to get with Undyne, Captain of the Royal Guard. Happy for Alphys and Undyne to have a relationship, Gaster was rather loose on Alphys' allowing the two to meet secretly when they wished. But an eventual tragedy would befall the couple when Gaster and Alphys worked on constructing the CORE. While working near the CORE's edge, Alphys tripped and fell in, with Gaster unable to save her.


Undyne remained as head of the Royal Guard, but held a reluctance against King Asriel and often questions serving the throne. As captain, Undyne could influence the Royal Guards to the best of her ability, but only a few saw her word as better than King Asriel. Undyne struggled with having to work with does who followed the King devotedly, as they went against her idea of justice for all. But the monsters needed her as their protector if anything went out of hand and so she remained in her place. She took out the tasks asked of the King, to many extremities but would occasionally draw the line. This made little difference as the other guards would do the work regardless.

Blaming himself for Alphys' death, Gaster returned to Undyne in shame explaining to her what had happened to Alphys and conforting her. He vowed to protect and watch over Undyne for Alphys' sake. From then on, Gaster would build all sorts of weapons and advanced armor for Undyne to use in battle. The two became the closest of friends and often practised using the weapons commissioned for Asriel's army.


Always wanting to be a star, the ghost Metta had asked the scientist Gaster if he could create a body for him to become one. However, King Asriel denied for Metta to be allowed to perform or be given a body and instead ordered for another ghost to have one instead, the Mad Dummy. Metta was left to return home in tears, comforted by his cousin Napstablook. Despite having lost the opportunity to become a big time star, Metta started a band with his two friends Shyren and Shyra, called Quiet Water. The band would perform in secret as to not be stopped by the King and would occasionally have Napstablook as a added member for special events.

Madaton (Mad Dummy)


Temporary Madaton Sprite

When Metta was denied the ability to be given a robot body, the King decided that the ghost who had previously be known as simply the Mad One was selected to take the place. Gaster was forced to build a new fighter for the King by the name of Madaton. It was said Madaton was chosen due to King Asriel seeing the same rage as himself within him. The new violent and incredibly mad new addition to the King's ranks began training to become a master human killer. Madaton's weapons include various dummy minions and a pair of swords he calls his 'knives.'


Having always supported Mettaton's dreams, Napstablook was enraged to find out that Mettaton was denied his chance. He grew angry and sad at the same time and often possessed an old training dummy to release his anger. He became the Sad Dummy, both mad and sad for Mettaton and for the Underground.


After being exiled by her son, King Asriel, the grieving ex-queen took refuge in the Ruins where she hid from the rest of the Underground. She was sad at the death of her husband Asgore and the actions of her son, but regained herself with the falling of the humans into the Underground. The first two which fell came but decided to leave Toriel to try and escape the Underground, to no avail. As a result, Toriel barricaded the exit and when the next three humans fell into the Underground, she cared for them as their mother. But when the seventh human, the soul of Justice, fell, he grew bored of the Ruins and convinced the other three to join him and escape out of the Ruins and try to reach the Barrier and escape, believing four to be enough. But all but Justice was vanquished, the last disappearing in the far reaches of the Underground, hidden. Toriel grew sad again at her failure to keep them safe and blamed herself harshly.


Temmie was one of the very few who survived the Great Tem Massacre. Fleeing with as many Temmie belongings as possible, she managed to survive in the shadows before getting a job as a fast food seller in Asriel Resort. The choice was so that she could spy on any who came from New Home or going to it for any news of the trapped Temmies or if the King would pass through. Temmie swore to kill King Asriel when given the chance as a sign of revenge for her fallen brethren.


As part of King Asriel's decree that all Royal Guardsmen take action, the war hero from the war between the humans and monsters, Gerson, was ordered to re-join the cause. At first with second thoughts, Gerson eventually re-joined to avoid anything becoming messy and soon took up his warhammer and armor again. However, he had to leave his home in Waterfall and live in the capital nearer the Royal Guard Headquarters in New Home. From there, he was re-given his rank from his previous service and was commissioned to watch the troops in Hotland. Theme: The Hammering.

River Person

In the case that a human would fall into the Underground, King Asriel wanted his Royal Guards to be able to travel from one place to the other as fast as possible and the only transport being the River Person and their boat was not good enough. The River Person was apprehended and forced to stop all travelling along the river. Instead, the Royal Scientist, Gaster, was asked to build a multi-seated boat system so that it was faster and with more room for Royal Guardsmen to get around. The River Person, with no where else to go took over Gerson's old home and began a shop and fortune teller's business for those who came past. They kept their boat but only for personal use and was allowed to keep their weapon, a scythe, which they hung at the back of the shop.

Riverpants (Burgerpants)

Originally called Burgerpants from his original job as a fast food seller in Asriel Resort, Riverpants took the job opportunity of operating the River Shuttle that Gaster had created for troops to travel around the Underground. It was better paid and was approved by King Asriel himself, so was the perfect job. However, he did not know the speed of the transport, and at first fell off the boat on his first try driving it (so called Riverpants as hey were completely soaked.) After somewhat getting th hang of it, he was reported as often screaming at the great speed but just managing to keep his sanity.

RG1 and RG2

With the Great Tem Massacre and the Burning of Temmie Village, the once small humble village was re-made as a lobby for the Royal Guard. Although no one ever went their, the small food counter placed in it was run by the unfortunate RG1 and RG2. Uneasy as it was to work there, the two took comfort in each other and grew secret feelings for each other after fighting each other for fun and eating the food they would have otherwise served. Theme: Guard Shop.

Monster Kid

Once it was Undyne who was seen as the coolest member of the Royal Guard and the hero to every monster child. But when the Great Lieutenant Papyrus was allowed to join, everything changed. Monster Kid and the other monster children became completely obsessed with Papyrus and dreamed of meeting him and becoming just like him. Monster Kid had the privilege to live in Snowdin, Papyrus's home and would often try and ring the doorbell just for an audience with their hero. Luckily enough, the Great Papyrus began teaching the Snowdin children and Monster Kid became his star student, following every instruction to the bone, learning to cook and how to fight for the Royal Guard.


King Asriel desired to grow his army for his future 'War of Revenge' and so Muffet and her endless number of spiders at her command was a perfect ally. He made a partner ship with her and anointed her a member of the Royal Guard. She became in charge of the King's Tax System charging gold for various things in support of the Royal Guard's growth. Her spider 'army' were soon armored and placed as part of the Royal Guard, rather as swarmed soldiers or as spies, to watch rebelling citizens. Spider Bakes, Muffet's company, became one of the few that remained after Asriel's rise to power as it was a part of their arrangement that it would go unharmed or taxed. Her title as Spider Queen has got into her head and although she currently allies herself with Asriel, her intentions are to get rid of him after the war has been fought. Theme: Queen of Spiders.


To serve drinks at his bar in Snowdin, Grillby is required to pay the Trade Tax to King Asriel with every drink and meal sold. Keeping tabs is against the law as part of the tax but Grillby does allow Sans to have one as the two are close friends. He often falls into dire straits when Grillby's does not make enough money but with the support of Sans and Papyrus, his too best customers, he manages to get through. Another problem is the promotion of the King and other businesses, propaganda for Asriel and advertisement for Papyrus and Muffet.

So Sorry

Few monsters owned the ability to create life in the history of their existence but on learning that one artist owned this gift, King Asriel ordered for his capture and imprisonment. So Sorry owned the ability to draw life that would manifest itself such as the Doodlebogs. This was perfect for the construction of a large monster army for King Asriel and so the locked up apologetic So Sorry was forced to practise and create weapons and soldiers for the future 'War of Revenge'.

Nice-Cream Guy

Before King Asriel came to power, Nice-Cream was a comfort and favourite to the monsters of the Underground. However, as part of the King's decree, it was illegal to sell anything without a permit or that stood against the King's propaganda. Nice-Cream Guy was a serious offender, selling Nice-Cream that talked about peace (something contradicting Asriel's plans for war) and for selling without the legal documents required. He was soon sentenced to imprisonment, for an unclear amount of time. Instead, his nice-cream vendor was repurposed for Muffet's Spider Bake sale.


Due to his key physical condition, Aaron was soon drafted into the Royal Guard. He was to patrol Waterfall for any intrusions, although he would often take breaks to flex for the passing monster ladies. Aaron did not really care about much and just accepted the King and his war. All would be fine for him as long as his muscular arms were safe.


Onionsan would always try and stay away from the Royal Guardsmen as they would always question him and his life, which got annoying and worrying. Then on one occasion he was taken and brought to King Asriel's castle. The King asked his to join the cause by becoming a Royal Spy, with his ability to traverse water ways throughout the Underground coming in handy. Onionsan refused, sending the King into a rage. King Asriel drew a sword and cut off one of Onionsan's tentacles. He told him that each time he would refuse him anything, another of his tentacles would be taken. In great fear and pain, Onionsan accepted and became a spy for the King. His wounded tentacle was never treated medically and never truly healed, becoming infected and sore.

Snowdin Shopkeeper

The Snowdin Shopkeeper abides King Asriel's trade law and pays tax for everything that she sell at her small shop. But when the tax became to much for her store to keep running, she turned to the King's spies as a solution. To bring down the tax and increase her payment, the Snowdin Shopkeeper works as a spy to those who enter her shop. However, she lacks the will to spy on children, as all rabbits love children and could never consider them as suspicious.

The Amalgamates

The Amalgamates were formed when the Determinations of Dr W.D Gaster and his assistant Alphys attempted to see if by adding 'determination to a monster's soul would boost their abilities and even allow for passage through the barrier. However, the experiments went horribly wrong when it was found that monsters lacked enough physical matter to sustain the Determination. Instead, they melted together and formed the Amalgamates. On report to Asriel, Gaster proclaimed the tested monsters to have died while he kept them secret and wrote to their family members explaining what had happened.

Memory Head

Nearly the same as in the original Undertale, Memory Head retains it's shape and design, however the faces of the additional characters seen in Slight Alteration can be seen inside of it's body. For example, Gaster's face.


While the original candidates for the Determination experiments were the Greatest Dog, Least Dog, Doggo's grandpa Dogamy's Cousin and Dogaressa's Mother (plus various smaller white dogs). But, as they were Royal Guardsmen of stronger abilities, King Asriel denied them allowance to be taken from duty. Instead, their relatives, Doggo, Dogamy, Dogaressa, Lesser Dog and Greater Dog were all admitted to the tests. However, when the determination experiment began to melt the monsters together, the Canine Unit melted into the Endogan. Endogan has a taste for petting, smoking and eating dog treats and nose nuzzling.

Reaper Chick

With all Final Froggits, Whimsalots and Astigmatisms having to remain on Royal Guardsman duty. Instead, a Froggit, Whimsun and Loox took applied for the Determination experiment. After melting and amalgamating together, they formed the Reaper Chick, a smaller version of the Reaper Bird. They also use the Everychild in battle, a younger version of the Everyman.

Melon Bread

Melon Bread is an amalgamate of an Aaron, Moldbygg and the cousin of Woshua, Woshuan. The reason was that Shyren's sister, Shyra, was convinced by Mettaton not to go, and so instead Woshuan took the opportunity. Melon Bread is stubby and arrogant, both sweaty and clean. The smell of Melons can be smelled when around them.

Friend's Forever

Catty and Bratty were so convinced by the idea of the Determination experiments that they were the first to apply. Trusting their friend Alphys that all would be alright, they willingly under took the experiment. However, they began to melt and amalgamate with two Vegatoids and formed Friend's Forever. The two best friends still talk to each other as they walk the halls of the True Lab, agreeing on everything but sad all the same.

Shyren and Shyra

With Shyra not taking part in the Determination experiments, she stayed with her sister Shyren and the two became a singing duet. Although both shy, the two hold small concerts with their other band member Mettaton. The band is called Quiet Water and the three have a small but well received reputation amongst the monsters of Waterfall, with Sans being their ticket seller at all their concerts and their fame kept secret from the Royal Guard. Occasionally, when Mettaton convinces Napstablook to come out of his melancholy, he pairs up with the band.

The Snowdrake Family

The Snowdrake Family stayed together because of Snowdrake's mother was to late to apply for the Determination experiments that Dr Gaster and Alphys were to take out. The laws that King Asriel set out demanded that all monsters were to be kept in the best health, and so Snowdrake's Mom never fell ill. Instead, Snowdrake's Mom and Dad set up a small store on the side of Asriel Resort. The family remained together until Snowy got upset at his parent's lack of belief in him becoming a comedian (not because of his bad puns but the lack of need for one in the current state of the Underground), and so he ran away to Snowdin to try his career there, to no success. The two parents remain worried for their runaway son but keep hope by them being together.

The Canine Faction

The Canine Faction were the elite relatives of the Canine Unit and were considered better skilled by King Asriel. For this reason, they were not allowed to apply for the Determination experiments and were instead spared becoming the Endogeny.


The grand dad of Doggo, Grandoggo was the one to teach his grandson how to use knives in combat. He also introduced to Doggo the wonders of smoking dog biscuits. After his grandson's disappearance, he took up Doggo's sentry station and tried to watch for any humans passing by. Instead of only being able to see things that move, Grandoggo's dim eyes only allows for him to see things that stand still.

The Least Dog

The Least Dog was the brother of the Lesser Dog. He is the shortest of the Canine Faction but the swiftest in combat. When given a pair of short sword, the Least Dog could give any opponent the 'least' chances to avoid an attack. His armor is light and flexible to give the most mobility. When patted, the Least Dog's neck shrinks into his body rather than extends.

The Greatest Dog

The Greatest Dog is the largest of the Canine Faction and the most strong. His immense stature and unblinking stare allows for enemies to become unsettled and scared of attacking him. The Greatest Dog's armor include a halberd and gauntlets, for crushing and piercing enemies. Although always with a smile, a sense of eeriness is always present around the Greatest Dog. Theme: Dog Chant.


Doghan was the cousin of Dogamy and the best man at Dogamy's and Dogaressa's wedding. Doghan often dreamt of having the same relationship as his cousin managed to have and hoped one day he would find his woman. As part of his longing for love, Doghan grew a passion for poetry and would right many poems himself.


Dogerie was the mother of Dogaressa. She was keen on her daughter's choice in marriage and was completely distraught on news of the couples ill fate. Dogerie would then cry out questions of why the two lovers had such an end. Her romantic-ness led her to try and match-make the younger monsters in Snowdin and the rest of the Underground, sometimes to a happy ending.


One of the very few Temmie's that survived the Great Tem Massacre, Bob used his intelligence to get out of Temmie Village in time to flee to the marshes of Waterfall. He made his way to Snowdin, where he layed low for a time. The last report of his appearance was when he made his way to the cliffs in Snowdin, assumed to have jumped but when checked no remains could be found.


During the Great Tem Massacre, the mushroom dancer Ragel could not escape due to being stuck to the ground. However, no remains were found after the great burning of the village to show that he had died. There was only a hole in the ground where he once stood. It is thought that Ragel was saved and brought with to the cliffs of Snowdin by Bob, but that is not confirmed by the investigations into the survivors of the incident.


Jerry is a Royal Spy for King Asriel as it was one of the few things he could do. However, his extreme dullness and boringness keeps all the other monster away from him before he can question them. He is a keen follower of King Asriel, who he calls his 'hero', and the 'War of Revenge' his chance to become more interesting.

The Six Humans

After Chara fell into the Underground, six more humans fell down afterwards. Each human had a soul corresponding to a particular trait. Patience, Bravery, Integrity, Perseverance, Kindness and Justice. The fates of the six humans all showed ill. (The names of the Humans are all unknown and so listed here as being called after their trait.)


The first human after Chara to fall into the Underground, Patience came during the time Queen Toriel still ruled. She was captured early on when exiting the Ruins, but was brought before Toriel who welcomed her with open arms. Patience was cared for in the Castle, waiting patiently for the time she could return to the surface when six more humans would fall. However, when Asriel rebelled and over through Toriel, he slaughtered Patience and took her soul.


The older brother of Patience, Bravery went out looking for his lost sister and fell into the underground himself. While entering Snowdin Town, he too was brought before Queen Toriel and welcomed. He found his sister and the two stayed looked after by the Queen until the rebelling of their adopted brother, Asriel. Asriel held a grudge against all humans and when he took over the throne, he murdered Bravery and Patience. Bravery's last act was to try and protect his sister, to no avail.


The dance loving girl, Integrity, fell down into the Underground while practising her ballet. She then met the exiled Toriel, who looked after her caringly in the Ruins. Although wanting to go back to the surface, Integrity could not get passed the blocked exit that Toriel had made to protect herself from King Asriel and for any humans trying to exit the Ruins. Integrity became a fond lover of puzzle solving, showing integrity throughout trying to solve them. Her fate, however, rested with the falling of the human Justice.


Perseverance fell into the Underground after trying to study in peace at the top of Mount Ebbot. After falling in, she was met by both Toriel and Toriel's adopted child, Integrity. Perseverance was then cared for by Toriel and became close friends with Integrity (The two being the only humans ment they had the most in common). Perseverance spent long hours listening to Toriel's detailed stories and snail fact books. She also loved bug hunting and she and Toriel would spend hours outdoors looking for them. She kept all her goings on in her notebook and drew in detail the monsters and insects she found in the Ruins. Her fate, however, rested with the falling of the human Justice.


The kind and loving human Kindness fell into the Underground when searching for the lost humans before him (as an act of kindness.) On falling, he joined both Integrity and Perseverance in being adopted by Toriel. He would often comfort his fellow humans when either of them were upset and would always do kind things for the monsters of the Ruins and his adopted mother. Kindness also had a passion for baking and cooking, often helping Toriel in the kitchen and perfecting the recipe for Butterscotch-Cinnamon Pie. His fate, however, rested with the falling of the human Justice.


Ill fate was imminent with the falling of the human Justice. Justice had heard of the tales of the lost humans of Mount Ebbot and was determined to find them. He climbed the mountain and jumped down into the Underground. To his surprise, he found three of the lost humans almost waiting for him. Integrity, Perseverance and Kindness all welcomed Justice and brought him to Toriel. Toriel took Justice in, at first with no problems, but Justice grew impatient and bored of the Ruins. His urge for Justice grew with the stories of the tyrannical King and the trapping of the monsters. He began to persuade the other humans to escape with him and head out beyond the Ruins. At first, they were all reluctant to leave but with the memories of the surface they agreed to the plan. Amongst the four of them, they managed to break through the barred exit and reach Snowden.

With each's particular skills coming in handy (Integrity with puzzles, Perseverance with observation and direction, Kindness with healing items and carrying, and Justice with strength and defence) the four managed to make their way through the majority of Snowden and into the depths of Waterfall. But on reaching the end of Waterfall and the beginning of Hotland, the humans were met with a large army of Royal Guardsmen, and the King himself. Their the battle of Waterfall began, with the humans holding against the oncoming of soldiers. But King Asriel locked them into deadly combat with Justice, distracting Justice from providing cover for the other three. First, Kindness fell, jumping in front of a blow that would strike the other two. The other two fled, but with Perseverance being too slow to out run the oncoming attackers, she got struck down. Finally, Integrity with a final confrontation, managed to hold against the guards until finally her integrity ran out.

Justice was the last one standing, still fighting Asriel with gun and sword. The King's army had left them to their duel and so only they remained. at Waterfall's edge. The battle went on until Justice took one shot that hit the King, grazing the side of Asriel's face. This gave enough for him to slash with a sword at the other side of the King's face, and blinding Asriel in the right eye. He then took the chance to flee, running back to were his friends were. He found only their bodies and the guards who killed them. Justice fought off as many guards as he could an made his way back through Waterfall, again seeing more guards and his dead friends. With Asriel and his army on his tail, Justice finally took a chance and leaped off of a cliff in Snowden and fell down into the depths of the Underground. In raged, Asriel demanded for Justice to be found, but no sign of him or his potential remains were ever found.


Robot-98 was the creation of Alphys when Dr. Gaster asked for her to demonstrate her skills. The robot was programmed with it's own intelligence along with a love of anime. It lived in Alphys room in the True Lab and would record the latest shows for her and discuss what would happen next with it's creator. On hearing the news of Alphys' death, Robot-98 shut itself down until eventually reanimating when Gaster began a search into bringing Alphys back. Robot-98 from then on assisted Gaster in his research and began it's own quest to find how to save Alphys from the void.

Grandpa Semi


Supposedly Grandpa Semi's House

The old skeleton war-hero from the War between humans and monsters, Grandpa Semi is the grandfather of W.D. Gaster. Grandpa Semi served as a Royal Guard along with Gerson, his closest friend, during the war and for a time when Asgore was still king. However, Semi decided to leave along with Gerson as they sought a more peaceful retirement. Grandpa Semi began an exploration of the Underground and kept notes of all the fauna and flora of the subterranean expanse, researched the full history of the monsters and even helped Gerson write 'A History of Monsters'. But when King Asriel rose to power, Semi completely disappeared into the depths of the Underground, only coming to visit his grandson, Gaster, from time to time. Some say the house seen from the cliffs in Snowdin is the home of the hidden skeleton.

Note: This is the current list of Characters for Slight Alteration. Any others characters are rather being saved for later or have been forgotten. Please leave any characters that I have forgotten to add or you think deserve a description here.



The Ruins in Slight Alteration remain mostly the same as in the original Undertale, but have a few changes correspondant with the events which occurred before hand. There is also a much larger expanse to the Ruins, stretching to the length of the entire crumbling city.

The Bed of Flowers

The first area of the Ruins is the Bed of Flowers where each of the fallen humans fell. The difference here is that the Bed of Flowers have various small objects and markings in the soil from each of the previous humans. Some were made as soon as the human had fallen, others while waiting for another. It can also be seen that a small gap in the middle of the Flower Bed can be seen where Gorey the Flower has rested in the sunbeams from the surface.

The Entrance to the Ruins

The entrance to the Ruins also has a flower bed where Gorey the flower tends to stay. It also leads the way to which Toriel introduced each human to the ways of the Underground.

The Various Puzzles

Each of the first few puzzles have had notes written for them by the fallen human Integrity. As a fond solver of puzzles, Integrity left detailed explanations on how to solve every puzzle in the Ruins most efficiently, sticking these on over the riddling signs previous to explain.

Spider Bake-Sale

An obvious sign of the problems of the Underground is the Spider Bake-sale in the Ruins. All the original prices have tripled with their owner, Muffet, charging massively on the monsters of the Underground. There is also a small group of spiders set to attack any humans or at least spy on them for report back to their leader.

Toriel's House

At the end of the Ruins is the house of the exiled Toriel. Kept tidy as usual, the interior of the house shows the signs of the previous humans who lived there. Instead of the room under renovations, it is open with two bunkbeds for the four humans who lived in the Ruins. The kitchen has several stains and marks from the human Kindness, the outside, neat garden and tree has arrows and notes for the best locations for bug hunting by the human Perseverance and the living room has a list of chores used to be done by the human, Integrity.

The Exit to the Ruins

The Exit to the Ruins below Toriel's house shows signs of the many attempts made by Toriel to securely barricade it. The signs of where nails held up planks of wood and rock were laid to stop any one entering can be seen around the door. The barricade served for both to protect Toriel from any attempts to by the Royal Guards to imprison her and so no humans or monsters can leave the Ruins, and so not get harmed.


Snowdin and Snowdin Town have been the forefront of King Asriel's re-enforcement of the surveillance of the Underground. More guards have been posted to watch for any humans and the inhabitants of the town well informed on the potential presence of a human. The running of the Snowdin Royal Guards is under Lieutenant Papyrus, of which whom all is reported.

The Gate

The Gate into Snowdin is far from non-defensive. Its bars are tightly packed together and its height lifted substantially. It was on order from the King that it should be radically updated from the Great Papyrus's original design and so was given the full treatment of defense. It is made up of a mighty gate with two menacing looking doors. However, it has the flaw of never being locked as a lock was never installed, so it can simply be passed through.

The Not-So Convenient Lamp

On the demand of King Asriel, all convenient lamps were to be destroyed and replaced by inconvenient ones in the case that a human should choose to hid behind one. The Not-So Convenient Lamp sits next to the Convenient Armchair, perfect for a human to hid behind. The reason for its existence is that no laws have yet banned the making of Convenient Chairs, and so on was made to replace the lamp.

The Box

The infamous box lover hid their box under a pile of snow, to keep it hidden from the Royal Guard. It is a capital offence to keep unregistered items that could be used for healing or battle and so all boxes are kept secret. The box is used most often by the children of the Underground, to keep sweets in or to teleport messages to one another.

Grandoggo's Sentry Station

The sentry station of Grandoggo has a sign that states that anyone who does go by should not stop moving, as Grandoggo can only see things that don't move. There is also the usual pile of ash and half smoked dog biscuits.

The Great Papyrus's Sentry Station

Having become the most famed member of the Royal Guard, the cardboard sentry station made by the Great Papyrus is seen almost as a shrine for the Snowdin children. Inside, they give small offering and gifts to their beloved hero, including lumps of snow, rocks and their own homemade spaghetti. Each week, Papyrus comes to this station and takes his gifts, leaving a note of thanks to each child who gave one to him (and an extra autograph.)

Snowdin Town

Snowdin Town is one of the more peaceful places in the Underground and retains its charms even when the King increased the patrol of it. The Royal Guards sent to patrol Snowdin spend many hours in its bar, library and shop, being distracted from their duty to enjoy the town like its residents do. Snowdin is also considered to be the true beginning of King Asriel's kingdom, with the Ruins being too distant and blocked off from the rest of the Underground to count.


Grillby's is the heart of Snowdin, the best place for a meal and for a rest. Although having struck hard times on the account of the trade tax, Grillby's always pulls through to continue selling burgers, fries and drinks to it's customers. The several posters in the window promote the King, the Royal Guard, the Spider Bake-Sale company and Pap's Pasta (Papyrus's spaghetti brand.)

The Librarby

The misnamed library in Snowdin is forced to keep books that paint the King in good light and the war against the humans as less of a loss but as a failure of the former King Asgore. It also stocks the tales of heroics done by the Royal Guard during the war and books on the many laws set in place by Asriel when he came to power. There is also a hidden section kept by the librarians for works that would otherwise be destroyed by the King, to lend to special members of the Librarby.

The Ice House

The Ice Wolf and his ice house have been replaced by a machine, on order that the Ice Wolf should instead be a member of the Royal Guard. His muscular build and keen health made him a desirable member and the job of throwing ice into the river a waste of a good soldier. Instead, the Ice House was rebuilt by Dr Gaster to throw the ice in on its own.


Those who live in Waterfall feel the eerie atmosphere and echoes of its tormented past. The echoes of those who were slain, and their cries for mercy solemn the monsters as they walk by. The marshes and quiet waters have their charms, both sad and beautiful.

Bridge Seeds

Although most of the Bridge Seeds were uprooted and growth controlled by the laws of King Asriel, a hidden outcrop of Bridge Seed can still be found in a hidden room in Waterfall as well as replantable seed packets.

The Wishing Room

The Wishing Room in Waterfall is a common place for the monsters to go, as they can wish to be free for their deepest wishes. Some wish for the freedom of the monsters, some of the War of Revenge. Others wish health or ill on King Asriel, depending. Even Asriel will come and wish for his war to come swiftly. Each of the echoes of the main characters can be heard on at least one echo flower in Waterfall.

Sans- ' i wish that I knew what all of this meant.'

Papyrus- 'I wish that I can know what to do as the Great Papyrus, for I am lost.'

Undyne- 'I wish I could be with Alphys...She would help me give everyone their hopes and dreams.'

Gaster- 'I wish for I to grow smarter, as I wish to free us from this place of misery.'

Toriel- 'I wish that my son would free himself from his wrong doing.'

Asriel- 'I wish that I, King Asriel, will have my 'War of Revenge!'

Metta- 'I wish I could be a true star, darling.'

Sad Dummy- 'I wish my cousin gets what he deserves...'

Madaton- 'I wish everyone was not so futile, Futile, FUTILE!'

The Bird That Carries You Over A Disproportionally Small Gap

The Bird That Carries You Over A Disproportionally Small Gap once transported all over the gap, but was forced by King Asriel to only carry those who had a license. By that rule, the bird is very suspicious of those who say they do have one, yet never checks.


The marshes in Waterfall can be lighten up with lanterns, mushrooms or crystals, but with the uncertainty of these methods, every Royal Guard is instructed to carry a lantern with them in case of any need to travel through these marshes. The complaints of the guards that patrol Waterfall can be heard on the echo flowers.

The Junkyards

The Junkyards in Waterfall are filled with the human waste that washes down into the Underground. On demand of King Asriel, these piles are searched of potential weapons or informations on the humans so that his War of Revenge can be planned successfully. Involuntary volunteers are asked to scourer the heaps of junk ever so often, with the occasional useful find of a lost knife or weapon, or maybe an old school or history book to find out their past weaknesses.

The Blook Family Theater

With Metta stuck back at home with Napstablook, the two decided to get rid of the snail farm, as there were no customers to buy any, and instead change it into a theater for the band Quiet Water's performances. Metta, Shyren, Shyra and occasionally Napstablook put on a small show for the monsters of Waterfall, but keep in mind to keep the theater a secret from the Royal Guard and the King. On the left of the theater is Metta's and Napstablook's houses, where they write songs and rehearse pretend shows if Metta was given the opportunity to be a big star.

The River Person

Not far from the Blook Family Theater is the home of the River Person, which once belonged to Gerson. In the small home in the wall of the caverns is the fortune-teller and riddler who deposits wisdom in whimsical forms to the monsters of Waterfall. Many of the riddles speak of the past horrors committed in Waterfall, rather massacres or battles, as well as the hidden secrets of the eerie waters. It is common for Gerson to revisit his old home and talk to its new owner, as well as receiving news of the future to come.

The Royal Guard Lounge (The Once Temmie Village)

After the disaster that was the Great Tem Massacre, the once Temmie Village was remade into a recuperation area for members of the Royal Guard to have a break. However few use it as it is said to be haunted with the spirits of the murdered Tems, as well as some guardsmen feeling the guilt of their actions during the massacre and refusing to be reminded of it. RG1 and RG2 were forced to work there to sell the food and drinks to their fellow guards, but with no customers they spend their time together and eating the food for themselves, despite occasionally being scared by the sounds of the haunting Tems.

The Final Arena

At the end of Waterfall is the Arena, famed for those who fight to clash. This was the site of the original battle between King Asriel and the soul of Justice, as well as the other humans of their band. The signs of the beginning of the great battle are shown on the rocks and the ground. This is also the strong point for whoever would wish to block off Waterfall and Hotland from each other, and the desired fall back point in the case of any failure in the 'War of Revenge', although few see the point.


The steaming, industrious world of Hotland is heavily favored by King Asriel for its uses to forging weapons and powering the CORE. With highly effective puzzles to dazzle any intruders, it is also one of the better guarded areas of the Underground.

Gaster's Lab

The laboratory at the start of Hotland is the home and workplace of Royal Scientist W.D Gaster. The interior holds a lab filled with machines, projects and blueprints, as well as hundreds of files of Determination all written by Gaster himself. It is far better organised than the original Undertale lab as it is taken care of by Gaster who prefers things kept tidy and accessible. The monitor connecting to all the cameras around the underground is partially hidden, to keep secret from the King, who may see it as a way to capture humans faster. The lab also has an elevator leading downward into the massive expanse of the True Lab, which has been greatly expanded to fit space for all the weapons and armors that the royal scientist has to build for the King.


It can be noticed that all the elevators in Hotland are as fast as possible on order from the King. Some are said to be so fast they make those inside nauseous. Any breakage in the elevators is rare, as they are checked weekly. However, the only person able to stop any of the elevators is Gaster, who secretly has a control to bloke off or breakdown one or more at a time.

Sans' Hotdog Stand

Sans' hotdog stand is a small but well received business in Hotland. Despite being illegal, Sans keeps up his business regardless of the rules. He sells all sorts of 'Hotpets' in this instance. Available items are:

  • Hotdogs- The not so suspicious kind.
  • Hotdogs..?- The 'totally not a water sausage covered in ketchup' one.
  • Hotcats- As usual.
  • Hotfish- Served with Hotchips.
  • Hothamsters- When put on a wheel they tend to run off.
  • Hotbirds- Light and airy, careful to not loss to the wind.
  • Hotguineapigs- You get the idea.

The Arsenal Room

With So Sorry having been taken into custody for use in creating King Asriel's army, the room that was once a place for art classes has been turned into a weapons room for Royal Guards. Inside are a variety of swords, axes, hammers, shields, armors and more to help prepare them for any potential fights. A notice was also put up to say that 'All Art Classes have been cancelled until the War is over,', implying that So Sorry is not be released any time soon.

The Spider Queen's Lair

Muffet's allegiance to King Asriel granted her high powers amongst the monsters. Her lair in Hotland is seen to spiders as a palace for their leader and is guarded heavily by spider warriors. Webs are everywhere and the whole room is filled with thousands of spiders. Those who walk in get caught up in the webs and those who are found displeasing to Muffet are soon dealt with.

Asriel Resort

At the end of Hotland just before the CORE is Asriel Resort. With Madaton being less of a glamourous figure King Asriel decided to create a resort to convince the monsters if the heroics of himself and the Royal Guard. The whole place is elegant and very well kept, with a large selection of rooms at the hotel and a restaurant with the best quality of food (as well as the most expensive.) Pictures of the heroes of the 'War of Humans and Monsters' and imaginations of the 'War of Revenge's ' victory are scattered around, along with many statues of the King himself. The guardsmen who pass through it every day are congratulated and praised by their fans, and winced at by their haters.


Both the power source for the Underground and the forge for King Asriel's Army's weapons, the CORE is a heavily guarded, technological structure which turns geo-thermal energy into electricity. Despite once having higher hazards and risks to it, the CORE was securely updated by Gaster (On the part that he lost Alphys there,) and so it became usable by the Royal Guard.

CORE Approach

The entrance is a bridge leading into the CORE, which is recorded by security cameras to prevent anybody entering without allowance. There are also guards who block the way in (RG3 and RG4), to add extra security. Only very few, such as the King, Royal Guardsmen and W.D Gaster may enter, as they all have passes.

The Forges

Throughout the CORE are forge stations to make the weapons for the Royal Guard and the King's army. The CORE was greatly expanded when King Asriel came to the throne on demand that the energy inside should be used for various uses. Previous workers at the CORE became smiths and soon took up hammers and anvils to make swords and other weapons. W.D. Gaster was given the job of overseeing the CORE's previous expansion and the current state it holds, which the Royal Scientist uses to his advantage by hacking into the countless security systems and having a breakdown mode on hand when necessary.

The Ice Wolf

Ice previously from Snowdin float down the river and reach the CORE to cool down the workings on it. As stated above in 'The Ice House' section, the Ice Wolf was re-instated as a member of the Royal Guard and was given a post in protecting the CORE. However he does not do his job well as he spends all day looking at the ice steaming, longing for his old job back.

Key Events

The Great Tem Massacre and the Burning of Temmie Village

The Temmies had kept secret their greatest weapon from the King, but when rumors were spread about the famed Tem Armor, it was only to much for King Asriel to desire. He ordered for the Temmies to hand over the armor but they refused. Asriel became enraged and ordered for a forceful attack to be made on Temmie Village. He sent the Royal Guard and a great fight broke out between the Temmies and the guardsmen. In the end many Temmies fell and the rest rather escaped or captured and interagated. The Tem Armor was found at the back of a crude shop and was given to Asriel in hand. He ordered that the village be burnt and re-built as a Royal Guardsman lobby, however none ever used it as the quilt of those who was slaughtered stayed heavy in their hearts.

The Battle of Waterfall

Famed in the history of the Underground as the conflict between King Asriel, his army, and the four human souls, Integrity, Perseverance, Kindness and Justice. In the battle, the two sides met at the end of Waterfall and eventually the conflict spread back to over regions of Waterfall. Three of the humans were slain, but one, Justice, was never captured. The battle caused the King's lost eye and scars, as well as an addition to his already strong rage. (See section on Justice.)


Chapter 1: Compliance

Chapter 2 Coming Soon. (Hopefully.)

The Next Chapter Awakens

What if I were to tell you that Slight Alteration has something else planned. Something new. Something different.

There may be only three routes in Undertale but this AU has something new to add. A second part.

While Neutral and Genocide are the same, a new pacifist ending will lead to a complete other story.

An addition to the Tale which more than doubles its length, explores new locations, has new characters and foes. A story of our characters being chased into the Underground's depths by King Asriel and his army, with new faces and old, and some in-between.

This will be all explained after the rest of Slight Alteration, so just wait for this next chapter.

Miscellaneous Information/Trivia

  • All useable cut characters will appear in Slight Alteration, as well as several characters from Deltarune and many completely new characters. Some of the characters to come include RG3 and RG4, Dohj, Susie, Noelle, Berdly and Rudy.
  • Other potential names for Slight Alteration were Altered Change, Converted Placement and Changed Placement, all now available for anyone who finds them suitable.
  • This AU was inspired by Paul Grote Beverborg's Undertale Corrupted Justice, also he is to thank for helping save this page from it's original near-deletion.
  • This AU is split into three parts, the Backstory, the adventures of Frisk in the underground, and the extended, yet to be revealed ending that extends the AU and the Underground quite a bit.
  • Any similarities to other AUs beyond Corrupted Justice were completely accidental and not on purpose.
  • Every character, even if they remain in the same role, gets a new or revamped theme than their original.