Bloody!Tale Sans Story

In a lab far underneath the underground, a skeleton named W.D Gaster was typing on his computer. He was creating a new entry for his project on artificial monster souls. Right when he stopped, he pressed a button and two tubes would illuminate. The machine which was attached to each of the tubes ejected slot which required you to place a vial of a soul piece for it to use.
Gaster looked down at his table and grabbed a sharp syringe. 
“This will all be worth it…” He said as he stabbed the needle into himself, sucking a little bit of his own soul into the syringe. He would place the little bit of his soul into two different vials, one for each of the tubes. As he pulled out the syringe, he staggered, walking to the first tube weak from the fractions of his soul lost. He would place the vial inside as the first tube started to begin its works. It was quite quick when the piece arrived inside of the tube. The soul piece started to form a thin, white transparent layer, forming what would seem to be the structure of bones. As Gaster analyzed it for a few seconds, he would walk to the second tube, placing the soul piece inside, resulting in a similar result. He would walk back up to his desk as he started to write down what he analyzed about the soul structures. 
‘The machine seems to be working well. I discovered that the thin layer of transparent substance I saw is made of bone marrow. Using my own soul was quite the sacrifice to both my health and my strength, but it will be worth it in the future. I just hope no one finds out about it.’ 
As time passed, days turned into weeks. The first soul piece was fully constructed into a full soul, along with the body of a skeleton. It was perfect, just like he wanted. As Gaster met up to the tube, he pressed a button to open it. There it was. Gaster creation, a skeleton, however with no name. The creation seemed quiet, as it looked back at Gaster. Gaster looked at it with E fascination before picking it up by his wrist to get a better look at it. Gaster smiled as he spoke to it.
“Hello experiment - 1.” The experiment could not respond. Both because of its unknowing to how to speak, and how to understand. He would walk over to the second tube, opening it as well, for it was ready as well. Experiment-1 met with the second experiment face to face. They both smiled, as if they knew they were related. As their small interaction began, Gaster’s sinister intentions did as well. Gaster used blue magic in both of their souls, walking into a large experiment room. The room had two chairs with braces to lock the hands who sat there in place. Gaster placed them both in each chair, as he walked out of the room. The two experiments turned to each other, panicking because they could not move. As Gaster came back, he held a tray with his floating hands. The tray held a hammer, some nails, and two custom metal plates, with numbers on them, each for their according experiment code. Gaster would walk up to the Experiment-2, placing the cold metal on the top of their knuckle. This would cause him to shiver. On the metal were four holes ment for screws but Gaster decided to use nails. As soon as Gaster placed the sharp end of the nail onto Experiment-2’s hand plate, he started to scream in fear with the voice of a young boy. In his other hand, he would take the hammer, slamming down on the nail, causing it to pierce through his hand. Experiment 2 would scream as the nail caused a gory sound of bones as it pierced through the knuckle, out through the palm, however this was only the first nail. The last three were quite quickly put in by Gaster, but the screaming just got louder and louder each time. After it was done, he would walk over to Experiment-1, him looking in fear.
“..I will do what I must…” Gaster said, as he slammed the first nail into his knuckle. His screams were more silent than Experiment-2’s meaning he could endure more pain. As this finished, Gaster threw them in a small compact cell where he would soon prepare them for more cruel experiments. As time went on, both subjects began to gain more knowledge, learning how to speak, and giving them the nicknames, Sans and Papyrus after their font name. Upon further analysis to both of them, Sans seemed more mature and more intelligent than papyrus, leading Gaster to have a good idea. 
Gaster created a third entity, what he calls, the Forbidden Hate. When he created the Forbidden Hate, he used plenty of illegally exported hate vials, compressing them using a gigantic air compressor and a hydraulic press, causing hundreds of gallons of it to be compressed into one singular vial, contained by glass as its cover, and a golden cap. The vial had special warnings of its side effects, but this became irrelevant for his experiment. Due to experiment-1’s maturity, Gaster was sure he may be able to control it, and if not him, Gaster may. Gaster led Sans out of his cell quickly, forgetting to close the door on Papyrus Gaster led him into a large room with Experiment 3 in the middle. Gaster sat in a room which had a window that led to the room, speaking through a microphone onto Sans. As this was happening, Papyrus escaped its cell, and escaped into the same room Gaster was in without him noticing. 
“I’m not sure if I should do this.” Sans said as he walked up to the vial, holding it in his hands. “It says not to drink it.”
“..Drink it, Sans.” gaster said through the microphone.
“I will not!” Sans said, but as soon as he did, Gaster caught Papyrus staring at him, and snatched him by the neck. Gaster summoned his floating hands, placing a sharp blade against his chest where his soul is located.
“You will do it, or your brother will die.” Gaster said as Sans gasped in terror. “Don’t do it!” Papyrus said, as Gaster placed the knife closer. 
“..I..” Sans stuttered, as he shivered in fear deciding what to do. 
“Don’t do it, Sans! Don’t worry about me!” Papyrus said, as Gaster faced him once more. 
“Be quiet.” Gaster said as he faced back at Sans.
“I won’t do it!” sans said, as he continued. “I’m tired of listening to you. Why should I? you hurt me and Papyrus all the time, so give me a reason why I should listen to you.” 
“This is why.” Gaster then used his floating hands to stab Papyrus in the soul, dusting him immediately. Gaster laughed evilly as he slowly dusted. Sans gasped as he clenched the vial within his hands. He clenched so hard that the vial started to crack. Experiment-3 started to leak through the cracks, causing the vial to completely break, and latch onto Sans’s face, entering his body through his mouth. His eyes soon became dark, as his bones started to crack and heal, as he grew to the height of a giant, standing at a whopping, seven feet tall. His teeth shattered and became sharp, and his fingers thinned slightly at their tips, becoming sharp. His eyes emitted with a bright red, as Gaster gasped. 
“..Just as expected.” Gaster said as he laughed. “Finally you will become my weapon of destruction.” 
“..Your weapon?” Sans spoke in an awfully distorted and deep voice. 
“… You’d be foolish to believe that I'd belong to you anymore..” Sans would say, chuckling towards Gaster, as Gaster was frightened by this.
“You will pay for what you did to my brother. I have full ‘hatred’ towards you.”
Suddenly, sans would lunge towards the double sided glass, shattering it and tackling Gaster, slashing his eyes into the iconic Gaster face he has today, after Gaster was bloodied and knocked out, Sans walked over to Papyrus’s dust.
“…Papyrus. I miss you already..” Sans said, trying to cry but he was unable to. However, he wasn’t the only one in control, his hatred was. Sans would sprint off finding an exit to the lab, going up the elevator into the main lab. Alphys was sitting at her desk when she saw a blurry figure standing from afar.
“W- what is that…?” She said, as she took off her glasses then put them back on, with no effect being on Sans. As she blinked, the figure would disappear as Alphys was put into fright and paranoiac fear, before her head being decapitated by Sans who stood behind her. As her lifeless body fell to the floor, Sans harvested off of her dust and body, absorbing her soul, making him slightly stronger. As he was eating, the door opened as Undyne entered, then her footsteps stopped as Undyne starred in fear, as Sans turned to her.
“YOU WILL PAY!” Undyne said, throwing tens of spears towards Sans. Sans got up, and started to run towards her, dodging each and every one of the spears. Undyne summoned a spear into her hands, as she blocked an oncoming hit from Sans’s claws. Suddenly he would snatch onto her spear, flipping her over and slamming her into the ground, causing her head to crack open and spill her brains all over the tiled floor. She would slowly fade to dust, as Sans slowly ate up the last pieces and absorbed her soul as well. After everything was gone, Sans walked past a model of a robot (mettaton) who was being created. Now that Alphys was gone, the robot would be discontinued. As sans passed by the Judgement Hall, his mind would flicker with memories of the timelines, as he witnessed a human kill him. From then on, Humans became a kill on sight for him. As he exited the hall, he entered the throne room, where Asgore sat. As Asgore turned to look towards his direction, he saw nothing as Sans camouflaged. Suddenly he appeared infront of him, choking him with his sharp hands. In the last moments of his life, Asgore tried to escape his grasp by imbuing fire over his face, causing Sans to roar at him and rip off his head, finishing him off. As he walked past Asgore, he entered the barrier, where the six remaining souls were held. Upon spotting them, Sans would absorb them into his body, giving him the ability to summon Chroma Hands just like Gaster, but one soul was missing; Determination. Sans sighed in frustration over his inability to break the barrier, so he decided to back into the underground to slaughter off all of the monsters of the underground. It was tedious, but that left him off with 50 LV, making him the strongest in the timeline, however as time went on, something changed. 
The player entered the underground. The underground was without life, and extra dusty. The player did not expect this as they walked around with the player controlling Frisk. As they arrived at Judgement hall, they spotted the blurry figure. 
“Is this some fan game?” The player said out loud in their room, as they used frisk to walk close to it. As soon as Frisk did so, they were killed by a swift slash to the chest by Sans. 
“..so you're the one who’s going to kill me.” Sans said, his head tilted down to the floor. 
“Well, let me tell you this, human. I ain’t going down easily. Let’s make this quick for the both of us…"Sans took time to think before continuing his next time.
“…It’s a silent day outside, the monsters' silent cries, the dust disappearing without trace, with times like these, humans like you… SHOULD HAVE THEIR BLOOD STAINED ON THE WALLS.” Suddenly Sans would summon his chromatic hands, blasting a barrage of Justice blasts towards the player. Every once in a while, the player would die and respawn at the end of the hall. Each attempt, Sans summoning bones, blasters, hands and explosives everywhere, trying to stop the human, but slowly the human adapted to these attacks and started avoiding them, eventually coming up close to Sans, slashing him with a powerful blade, the REAL KNIFE, dealing 99 Damage to him. Blood was over his chest as the human stepped back to smile in victory as Sans knelt onto the ground. 
“..You slashed me.” Sans would start to chuckle, causing the player to be frustrated and attempt to slash Sans, however Sans would use this opportunity to penetrate Frisk's torso, grasping onto Frisk's soul of determination. When this was done, the player could not control Frisk due to the soul being the only key for the Player to control Frisk. The player became frustrated, so the player went to the menu. Right as the player opened the menu, Sans absorbs Frisk's soul, giving him the power he needed to break the barrier. The player looked at Sans through the screen, looking  at him with hatred before using a RESET. However, the RESET did not make the animation nor the sound it was supposed to do, returning the player back to the game from the menu. Upon Sans absorbing the determination, it granted him the power to resist the effects of a RESET, therefore he stood in the same position as he was before. The player was frustrated because they were unable to move Frisk and unable to move. 
“..See ya later, ya little murderer.” Sans said, as he walked out of the hall. The player decided to close the tab of Undertale for a while, but it failed due to Sans’s resistance. The player walked out of their seat seeking a way to turn off their game. While this was happening, Sans broke the barrier, causing Frisk to disappear as the ending cutscene would begin. As Sans stood on the ledge of the mountain, he looked over the city where the humans inhabited. 
“…There’s more of them.” Sans would disappear from the cutscene, then the player was met with the credits scene as Sans progressed down the mountain. Sans walked through the forest, spotting a human child among the bushes. Sans hid from the child, as the child noticed the ruffling sound. The human child was put into fear, as she sensed something behind her, which was Sans. In that moment, Sans punched her into the ground, causing her nose to bleed and her to scream. The scream could be heard from the city, calling attention to the forest. As Sans looked down at the child, he continued to punch her until her screams were silent. As he looked down at his hands, his hands were covered in human blood. With a curious smile, he tasted the blood from his hands. He himself disliked the taste, but his hate did. This caused him to become controlled and tempted by the hate to rip apart the human, which he did. By doing this, he would harvest the human and eat her flesh and blood, but the hate absorbed the blood into Sans’s body, granting him the ability to manipulate blood. By doing this, Sans would summon a blade made of human blood, a scythe. Suddenly Sans would notice the sound of footsteps, leading him to climb the tree. A group of humans were heading towards his area. Upon arriving a few of them threw up from the dead corpse. As one of them got close to it, looking upon her with tears, Sans landed behind them, snapping their neck, then going so far to remove it from her body. The humans tried to stop Sans, but their weak human attacks could not fend off the powerful monster, causing the area to become bloody. As more and more humans heard the screams, many of them decided to evacuate the city, but just as they left, Sans arrived, going on a murder spree that the humans could not stop, even with teamwork. His abilities were too strong for them to stop, causing the population to slowly deplete, until there was nothing due to his genocide. The timeline fully emptied, as Sans stood there alone in the rubble which the city used to be. Suddenly, a portal would open up across from him, and a figure walked out that looked similar to him. 
“…Hm, this is a strange world.” The figure said. His body was pitch black and he wore blue, red and yellow. His eyes leaked strings which were blue, and every few seconds, he glitched. Upon the figure noticing Sans, he looked at him in disgust.
“Ugh what is that?” The figure said, walking closer and stopping a few feet from him. Upon noticing the sound of his footsteps, Sans turned. His face was completely shadows voiding it of visibility. Sans would stand up, giving off the blurry appearance such as from before. The only thing visible on his face was his eerie glowing red eyes, which stared at the figure. 
“..The hell?” The figure said, stepping back. Soon the steps turned into running as Sans accelerated towards the figure, entering the portal with him as he dropped onto the bright colored ground of the other side. This room was extremely large. From the roof hung papers suspended by the same strings which leaked from the figure’s eyes. 
“…Interesting…” Sans would say, as he looked at the figure a little bit more. Suddenly another portal would open up, with another figure. This second figure wore white and brown clothing, with vials going across his chest and a large brush on his back. Sans would run up to the first figure, slashing their blood scythe at them.
“WHAT THE HELL!” The first figure said as they dodged the slash. Suddenly the first figure summoned four glitchy gaster blasters to fire at Sans. Sans looked upon their attacks, and recognized it, causing the hate to copy the attack and for sans to use it as his own. Suddenly, a puddle of blood surrounded the first figure and Sans, causing bloody gaster blasters to come out of the pool of blood, shooting red rays of blood and energy towards the first figure. The first figure dodged the oncoming blasts, while the second was astonished. Suddenly Sans would summon a gigantic version of the blaster, causing the second figure to shout: “WATCH OUT, ERROR!” 
The second figure would jump in front of the blast, pulling out their brush and covering the blast with an ink shield. Error pushed the second figure away saying, “I DON'T NEED YOUR HELP INK.”
Error would dash towards Sans, summoning bones above him, and stringing them, slamming them down where Sans stood. Sans would block them with his scythe, and redirect them towards Error, which he dodged easily. As he dodged this, Sans jumped towards error, hitting him with a strong slash downward, causing a slash to form on Errors chest before glitching away. 
“YOU WON'T KILL ME THAT EASILY!” Error said, as he summoned a high quantity of blasters that fired consecutively towards Sans, however each time that he fired, Sahs would adapt to his attacks, becoming faster and harder to hit, until Sans arrived infront him, roaring towards his face.
“JUST DIE ALREADY!!!” Sans would say as he barraged Error with slashes all over his body, causing Error to be launched backwards, kneeling down in pain. These slashes slowly glitched away, but that didn’t stop Sans. Sans dashed towards Error, causing a puddle of blood to form beneath them, and chains made of flesh to stun Error.
“THE HELL IS THIS?!?” Error would say as he looked down at the bloody chains, but before he could say anything else, a gaster blaster would summon infront of him, ripping him from the chains as it blasted towards him. 
“..UGH! YOU STUPID ANOMALY!” Error would say as he tried to aim his strings towards Sans, but he was nowhere to be found. Suddenly Sans would use his special technique, AGGRESSIVE TELEPORTATION which teleports the user, but depending on the distance of the teleport, it causes and explosion to form where they appear. As Sans teleported to Error, Error would be launched down into the ground, causing to be pretty hurt.
“I'D LOVE TO FEAST ON YOUR BONE MARROW.” Sans said, lunging at Error with the intent to kill, but suddenly Ink interrupted pushing him to the side. Error looked weak on the ground, damaged from the slashes and constant attacks.
“That’s enough.” Ink said, as his eyes flashed red with determination, and his face expressing determined anger. 
“I won’t let you finish him off. The multiverse needs him for the balance of creation and destruction, if you kill him, the multiverse would need to be balanced.” Ink said as Sans stood from afar.
“..Does it look like I care?.” Sans said, causing Ink to sigh of frustration before getting in a defensive stance. Sans would lunge towards Ink, causing him to block his bloody scythe with his brush which didn’t snap. Suddenly Sans would summon plenty of more bloody gaster blasters, as Ink would dodge them easily. Ink would sink into the ink appearing right next to Sans, slashing him from behind, but Sans parried his attack in a spin move, causing Inks brush to be launched backward. As this was happening, a pool of blood spilled in a large area around him, causing flesh chains to chain up ink and error. 
“Crap!” Ink said as he tried to escape, but he couldn’t. Suddenly most of the blood was siphoned into Sans’s scythe, creating a large sphere which hovered over his head. This large sphere was completely made out of blood and flesh, so much that you could hear the screams of his victims. Suddenly Error would be filled with anger, causing him to get up in adrenaline, and cause him to summon a hundred blasters at once to oppose the sphere. Suddenly the sphere would explode as Error fired, causing many papers around him to be stained and ripped apart. In result, Error would fall to the ground, covered in Sans’s blood, exhausted. Ink would be exhausted as well, while Sans hasn’t even shedded a single sweat, not like he could anyway. 
“You will never destroy the balance of the multiverse.” Ink would say exhausted.
“Who’s stopping me?” Sans would say, chucking, but with inks last bit of energy, and errors too, Error would string sans, and Ink would create an ink puddle portal to swiftly launch Sans into another AU.