* To know more, see:
Note from the Creator:

It's fine to use anything on this page. Please ask permission to use this AU in any RP since it's my own AU. Mystic and Gen have a very....weird relationship in the end. As in the infobox, this is a WIP.

"If you promise not to harm these children I will hand myself back to you and your relentless torment. If you betray this statement however, I will hunt you down and finish you off myself"
– Mystic Shadow (V03G)

GeneticTale is an AU created by Lightningstrike5757.

This alternate universe is not much different to Undertale with only one major change. A monster was created. The monster was meant as a means to destroy the barrier and wage war on mankind. Using a combination of DNA, this monster was created as a non-sentient living weapon capable of wiping out entire army of humans. There is one fatal flaw however. The monster is sentient. This story circles around the young genetic hybrid and her life from lab to the forest, and to home. It also gives information about what caused the great war that trapped the monsters underground and who caused the story to take place. It is currently set in the year 200X.


Undertale characters


Like original sans he is is chilled back and lazy to most. when he is at his work however he is the most hardworking monster. he was the one who came up with the idea to create a living weapon and is in command of the genetic weapon project or GWP. he is papyrus's older brother and the older son of Gaster. he is a scientist but is anything but weak. he is the second strongest monster in the underground and donated his own magic and DNA to the creation of the third and final genetic hybrid V03G. he will call her by that name and that name only. he cares a lot for papyrus but despite the fact that Mystic is in a way his own daughter he will not treat her better than his own blasters. he also refuses to see the fact that she is sentient and treats her like a weapon or tool. that is why she hates him. he is partially blind in his right eye due to a science experiment with the CORE gone wrong. the CORE had damaged his eye in a small explosion. his left eye can glow quite easily but his right eye will sometimes flicker blue when he is extremely mad. he wears an Azure blue hoodie and an ivory coloured T-shirt underneath. when doing checkups on Mystic who he simply calls V03G he wears an ivory coloured lab coat over his shirt. he wears Midnight black shorts with a Azure blue stripe running down each leg. he also wears navy blue sneakers with loosely tied laces. his stats are very high due to FIGHT's and combat training with V03G. he can use a weaker version of Mystic's own blades and can only use one. he has mutual feelings for V03G. the scratch studio is partially correct in their personalities. he is about 12 since this is set in the past of GeneticTale. he is very suspicious of Mystic and believes she will use or harm papyrus. sans cares deeply for papyrus but will but his work over him. his universal nickname is Gen


Royal scientist and second in command of the GWP. The loving father of Sans and Papyrus. Since this is set far back in time he has not fallen into the CORE yet. He wears a black lab coat and does not have cracks running down his face. Gaster still has holes in the middle of his palms and has a slightly smaller stats than King Asgore. He can use blasters, blue magic, blue attacks and bones.


A young lovable skeleton who is about 6 years old. the younger brother of sans and the youngest son of gaster. he is innocent and absolutely adorable. he has a lot of friends who are about the same age as him and is oblivious to the experiments that sans and gaster have conducted. he is very innocent and does not know how to use magic yet. the most he can do is summon a bone or two. he is 10cm smaller than sans. he wont be oblivious to the experiments soon though . . .


King of the underground. sort of depressed and misses his wife. wonders why Astra started the war.


Undyne is younger and second in command of the royal guard. she is the apprentice of Gerson. has a small crush on Alphys. she is 11 years old.


Coming out of his prime and is thinking of retiring and giving the captain role to Undyne. he is the captain of the royal guard.


Keeper of the ruins and as of late is oblivious to the genetic experiments.


Runs grillby's in snowdin town.


Trying to get the other spiders out of the ruins. failing due to her pastries being overpriced.


Isn't nervous or jittery due to the DT experiments not being conducted yet. she is an assistant for sans and gaster and responsible for measuring out the DETERMINATION fed to Mystic. hasn't created flowey yet either. has a crush on Undyne but is afraid of telling her. Alphys is only 10 years old.


Has yet to fall. Still has the DETERMINATION soul trait.


Still lives in temmie village in waterfall.

Annoying Dog

Working on something in the secret room in snowdin.

Added Characters

Mystic Shadow (V03G)

The third genetic experiment and the protagonist of the story. She is a genetic hybrid capable of wiping out the human race by herself. The reason she is the third but main character is for the reason that the previous experiments had died out due to a lack of the necessary food to sustain them. They probably had it better. Her DNA consists of Wolf, Scorpion, Dreemurr, Human, Skeleton and Blaster Dragon. She is a kind soul who doesn't want to FIGHT or use violence but instead tries to promote MERCY. She will only FIGHT when forced to, attacked, or provoked. She has a mainly wolfish body but has three tails. One of which is a scorpion tail made of bones. Most think she is fully grown but that is an actual lie. She looks like 8 years old physically but mentally is more like an adult than most other monsters. When she is truly fully grown, she will actually gain horns like Asriel Dreemurr (god of hyper-death). She can fire a powerful beam from her mouth which is twice as strong as a regular blaster. When she dislocates her jaw, the beam can drain magic and DETERMINATION from its target which she uses to sustain her body. She can withstand tones more DT than the regular monster due to her reliance on the stuff. If too much is put into her body, she will melt. Her fur is white and her tail tips are azure blue. Her eyes are silted and instead of white on the outside they are black. With black pupils and azure blue irises. She can summon bone blades which drain her magic about a 10th she prefers to use 5. She can also use orange and blue attacks as well as blue magic. She uses bones, blasters and fireballs. Despite that she is the most powerful monster and that should make her power hungry, she refuses to FIGHT for power and instead for peace. She loves to sing and songs are how she often spends the time. She can convey messages through them. She is also great with kids and hates Sans and Gaster. She made her name herself since she believes she deserves the rights of any ordinary monster despite the fact she was made as a living weapon.


Not much is known about this monster. she was supposedly the last Blaster Dragon alive and started the war. reason is unknown. she had dissapeared the day the monsters were banished underground.


Undertale Locations

  • The Ruins
  • Snowdin Forest
  • Snowdin Town
  • Waterfall
  • Hotlands
  • The Core
  • New Home
  • The Castle
  • The Barrier Room

Added Locations

The Labs

The Labs are bigger and go deep underground. This is the hub for all science activity in the underground. The true lab also does not exist as well as the amalgamates due to it being in the past.

The New Underground

This is a massive cavern that is half inside and half outside of the barrier. There are only a small amount of ways to find this place. For outside of the barrier half, one can find it by stumbling upon its outside entrance or lead there by others who have found it. Inside the same rules apply but since magic is alive and well there is another way to find the tunnel to this magnificent cave. You can be lead there by wisps of golden flame which only reveal themselves to children. Only young children and a few selected adults are lead to the cavern. The entrance resides behind a thick bramble bush in the forest of Mount Ebott. If you are uninvited a golden flame will shoot up and block the entrance. If you are invited the flame will not harm you. There is a lot of plant growth and big ferns can be found in the cave. Smaller caves have been cut into the sides of the cavern to give privacy and sleeping spots for residents of the underground. All and all a paradise and the one part in the entire underground that has no adults or any contact with the scientists. I wonder who will find this place...

Flowers Grotto

A place inside waterfall with all kinds of flowers. There are buttercups, orchids, tulips, echo flowers that come in every colour and a few blackberry bushes. This place is a sacred,and is well cared for by the residents of waterfall.


  • Some species of monsters can fly and grip the cavern roof
  • In this AU frisk is female


  • The new underground was inspired by the Natural bridge on Mount Tambourine
  • Mystic Shadow is from a werewolf name sheet using the Authors own initials
  • the idea of Mystic being a genetic weapon came from the indoraptor in Jurassic World fallen kingdom
  • Mystic was originally going to have dragon wings
  • the story was originally thought out and then changed drastically while the prologue was written
  • the golden wisp idea came from the movie BRAVE


The rest of the story cannot be told yet.