Animosity!Sans

Animosity!Sans is quite potentially one of the most dangerous Sanses lurking within the vast Xenoverse and beyond, though there could quite very well be far more dangerous out there, but that isn't the point right now. He is the result of a failed Pacifist Route in Underfell from a very distant Multiverse from the main one where Asgore ends up killing the human child, using their harvested soul and the six others that he had collected to transform into an absolute god, single-handedly breaking the Barrier with ease before sealing it right back up with the power of the absorbed human souls being the abhorrent sadist that he is. How this all results in Sans becoming a hyper demon capable of destroying whole Multiverses at a time? All of that will be explained in the backstory section.

Backstory
The human child had just made their way into the Final Corridor, the only thing standing between them and finally confronting the ruthless monarch of the Underground was the judge, Sans. The fate of their journey would now be decided by the skeleton standing before them, let us hope that he is merciful upon them... "...so... youve uh... wow. im genuinely at a loss for words, you managed to turn each and every single one of those dickheads back into goody two-shoes, especially my brother. its becoming kinda clear to me that you have some kind of special talent inside of ya, seeing that you somehow managed to convince even my BROTHER to become a better person. tell ya what, i think you might actually have a chance at trying to convert ASGORE. y'know, that fucker thats basically made everyones lives a living hell? anyway, just try not to get brutally slaughtered, if everyone found out that i let a false glimmer of hope pass through and let asgore fuck us all over by absorbing your soul and basically becoming a god because, lets face it, that douchebag is no doubt going to abuse his power, im going to be absolutely FUCKED. you got that? Do not disappoint..." With that being said, Sans would teleport out of the room, allowing the human to make their way towards the Throne Room. Once there, they would be greeted by a goat-looking monster who looked to be much like Toriel but with facial hair sitting upon his throne. "...I take it that my incompetent judge had been fooled by your 'kindness.' I'm beginning to wonder what drove me to choose that slothful waste of space in the first place..." Asgore would get up off of the seat of his throne before motioning his hand for the child to follow him. "Come with me." The monarch would make his way through the exit of his Throne Room, the human child following behind him. Just before entering the Barrier, the child would SAVE at the nearby SAVE point. "I see that you've taken a liking to these strange star-like entities." Asgore would begin to chuckle lightly. "Say, why don't we make the upcoming inevitable a bit more... interesting..?" The boss monster would ask before whipping out his bright-red trident, slashing the SAVE point to bits rendering it completely useless, also destroying the human's SAVE file as the SAVE point was the only one that had housed their file. In other words, if the human were to suffer a grim fate against this sadist, all would be lost, not even a second chance would be offered, the human would truly be no more... Asgore would then grab the human by their wrist before dragging them into the Barrier, once there seven jars would emerge from the ground, six of which were filled with souls, each being a different color. "Human... I trust that you know what's going to happen next..." Was the last thing that the human heard before he shattered their MERCY button before almost immediately getting pelted with boiling hot balls of flame, luckily the human was able to dodge enough of them to still have 4 HP left. They would use their turn to quickly look through their ITEM menu before regaining 10 of their HP with the only MonsterCandy, they knew that they had to make this count. Asgore would begin to throw some more fireball attacks at them before realizing something. "Human, it would seem that you underestimate what I did to your MERCY button just earlier... don't think that I'm not capable of doing the same to your other buttons." Asgore would use his trident to shatter the human's ITEM button. Things were looking grim for the human child, they only had 2 HP left and they couldn't even heal anymore! Not only that, but Flowey was inconveniently nowhere to be found, especially in a dire situation like this. Come to think of it, Flowey hadn't been with them for over half of the length of their journey. The human would begin to do the only other thing that seemed helpful... * BEG They would begin to beg for mercy at the feet of the ruthless boss monster that towered before them...
 * Multiverse #000645854
 * Universe ID: "Underfell"
 * Timeline: Pacifist

To no avail. Asgore would impale the human child with his trident, draining them of more than the very little remaining HP that they had. Their soul appearing over their corpse, on the verge of shattering, Asgore would swiftly take the fragile soul from their body. "Such a pity, I imagine you would have stood a much better chance if you actually FOUGHT at all..." Suddenly, out of nowhere, the lids of the other six jars with souls in them would begin to open up as the souls that filled them would begin to hover out from them, all of them including the damaged soul within the boss monster's hand would begin to circle him, radiating their power into him. The whole room would begin to light up in a bright white shine before an earth-shattering shockwave emerged from Asgore, surging throughout the entire underground.

Back in Snowdin
After having teleported back into Snowdin once he got done with judging the human, Sans would walk back to his and his brother's home. Once there, he would unzip his jacket before lazily throwing it onto the floor before taking a seat on the beige-ish colored worn out couch that sat in front of the barely functional television set. Though, it was hard for him to get comfortable due to having thoughts about the human potentially sealing their fate against Asgore, he would begin to twiddle his bony thumbs anxiously as these thoughts continued to circle his mind. "ahh, calm your tits, sans. 'kid was able to transform undyne and papyrus into better people, two of the most sadistic royal guard members, why wouldnt they be able to turn the king's ways around? yeah, come on, youre just being a pussy." Sans would try to reassure himself in his head, suddenly beginning to feel a bit more relaxed, he had hopefully nothing to worry about. The human would be able to convince Asgore to become a better person with no problem at all, they've shown that they were very much capable of doing so with everyone else, so how would Asgore be any different?- FSHOOOOOOOOM! Out of nowhere, a massive shockwave took out the entire upstairs area of the house, leaving nothing but the downstairs roofless! "WHAT THE FUCK-" Sans would begin to spazz out on the couch before falling face-first onto the floor. He would try to pick himself up off of the floor before hearing the door suddenly burst open with incredible force... It would seem that Papyrus was quite mad. "SANS!!!, WHAT THE HELL HAVE YOU DONE!?" Papyrus would grab Sans by the turtleneck of his sweater. "ALL THIS TIME I'VE BEEN TRYING TO BETTER MY WAYS, AND FOR WHAT? TO LET SOME HUMAN CHILD BASICALLY GIVE KING ASGORE THEIR SOUL!? YOU'VE FUCKED US ALL, SANS!!" Papyrus would throw Sans against the wall, knocking the breath out of his... uh... whatever he uses as his lungs..? "h...how... wheeze... how do you know..?" Sans would question his brother before receiving a swift kick in the jaw. "ALPHYS TOLD ME AND A LOT OF OTHER MONSTERS WHAT HAD HAPPENED, SHE SAW THE WHOLE ENCOUNTER THROUGH HER LAB CAMERAS... SEEING ASGORE IMPALE A KID WITH HIS TRIDENT BEFORE YANKING IT FROM THEIR BODY DOESN'T REALLY TELL ME THAT THIS KID IS THE HOPE FOR ALL OF MONSTERKIND!!" Papyrus was absolutely furious, there was barely anything keeping him from murdering his own brother right now, though he couldn't muster up the strength to do it. "YOU KNOW WHAT... JUST- JUST GET THE HELL OUT. YOU ARE DEAD TO ME..." Papyrus would grab Sans and push him out of the door to their house, locking the door once Sans had made contact with the snow on the ground. Sans couldn't believe it, the human child actually wasn't capable of changing the king's ways, thanks to him Asgore had become a full-fledged god. Not to mention, just as he mentioned to the human child before their untimely death, Asgore would no doubt abuse his power as an all-powerful god as he could already hear the distant booming of fire and brimstone as the former monarch turned god began ravanging all of Hotlands with ease. Sans knew that he needed to hide somewhere, from everyone else too, as they would no doubt give his location away in an attempt to try and spare their lives from Asgore's unholy wrath. Seeing as there was nowhere safe in Snowdin to hide with all the monsters around, he would begin to summon a bone to hurriedly dig a hole in the snow with so he could bury himself until he was absolutely sure that Asgore was bored of laying waste to Snowdin... ...Several hours later, Sans could no longer hear the sounds of destruction. As a matter of fact, the entire Underground seemed silent, dead silent... He would begin to rummage through the snow to catch a glimpse at the most horrifying thing that he could have possibly seen in all of his years under Asgore's rule, Snowdin was nothing more than a destroyed wasteland, piles of dust on the ground wherever he looked, he was quite certain that his brother Papyrus had been killed during Asgore's massacre. Sans was completely destroyed on the inside, the place that he had lived in for basically all of his life, all of his former friends and family, all ravaged in mere hours by a wreckless god. Sans was pretty much the only survivor, all alone the desolate Underground, so he had to fend for himself now...

Several years later
Sans wasn't sure how much longer he could take this, it has been several years of nonstop wandering around the destroyed remains of the underground, not a single remaining living thing left in all of the Underground. His teeth have rotted to the point of growing discolored and gravelly due to going so long without paying attention to his personal hygiene, though it's not like anybody would care anyway, they were all dead. Though, just out of nowhere, Sans was just now beginning to realize that after several years of being completely alone with literally no other living thing to accompany him, he had begun to feel some sort of euphoric feeling of peace within him that he hadn't felt in all of his time of being alive up until the point that Asgore slaughtered nearly everyone in the Underground. If anything, he had felt a lot more... happy. He wasn't quite sure if this was because everyone had treated him like utter garbage all of his life or if he was starting to go insane from being alone for so long, but whatever the reason, he much preferred this lifestyle over one with people to actually give his life meaning. Though while Sans was happily contemplating how he preferred a life of loneliness, an earth-shattering booming voice erupted from the Underground's ceiling. "THERE YOU ARE..." Suddenly, Sans could feel the earth beneath him being torn in half by an unknown force! The roof of the Underground practically exploded into a million chunks, floating off into the vast space. What Sans could see once the ceiling was torn off was a colossal, hideous eldritch entity shining off multiple colors of the rainbow with a giant prismatic soul at the very middle of it, all the while wielding a... a trident..? Asgore..? "AFTER YEARS OF SCOURING THE VAST MULTIVERSE, RIPPING APART UNIVERSE AFTER UNIVERSE LOOKING FOR YOU, I'VE FINALLY FOUND YOU... A giant, malformed arm would reach down towards Sans, grabbing him up off of the ground before getting him up close to Asgore's face, or whatever even closely resembled a face. "ALLOW ME TO ASK YOU SOMETHING... DO YOU KNOW WHAT 'LOVE' IS..? Sans would begin to put in a great effort in struggling in the being's grasp, obviously to no avail. "LOVE IS MERELY JUST AN ACRONYM FOR SOMETHING FAR GREATER, MEANING 'LEVEL OF VIOLENCE...'" "nngh... why are you... hnngh... why are you telling me this..?" Sans would ask amidst his futile struggling. "I TELL YOU THIS BECAUSE ALL THIS TIME, I HAD THOUGHT THAT THERE WAS NOTHING MORE POWERFUL THAN THE POWER A HUMAN SOUL COULD GIVE A MONSTER... YET I WAS WRONG... SO VERY WRONG... I'VE WASTED SO MUCH TIME EXECUTING HUMANS TO HARVEST THEIR SOULS FROM SEVERAL MILLIONS OF UNIVERSES THAT I WAS COMPLETELY BLIND TO THE LOVE'S CAPABILITIES AT SUCH TREMENDOUS NUMBERS..." "...again... nngh... why are you telling me this..?" Sans would ask again, hoping for an actual answer from the almighty elder god before him this time. What would happen next was that all of the cosmos around the two would begin to quake as Asgore began to chuckle. "FUNNY YOU SHOULD ASK SUCH A QUESTION... I TELL YOU THIS BECAUSE YOU ARE THE LAST KEY COMPONENT TO RAISING MY LOVE HIGH ENOUGH TO BREAK FREE FROM THIS RESTRICTIVE MULTIVERSE... ONCE I BREAK FREE, I'LL BE ABLE TO CONQUER THE ENTIRE METAVERSE, EVERYTHING WITHIN IT WILL BOW DOWN TO ME... I'LL FINALLY BE THE ULTIMATE MONARCH..." Asgore would toss Sans at nearly the speed of sound before attempting to slash him with his trident... He was able to land a hit on him... Though the hit barely scraped him, it still managed to create three large, gaping wounds in Sans' torso, alarming amounts of blood leaking from the wounds. Asgore would reach back out for the damaged skeleton, bringing him close to his eldritch self. "YOU NEVER REALLY WERE A LIKEABLE MONSTER, WERE YOU..? EVERYONE AROUND YOU FELT NOTHING BUT DISAPPOINTMENT WHENEVER YOU WERE IN THE SAME PLACE AS THEY WERE... THOUGH I CAN'T SAY THAT I DON'T UNDERSTAND WHY, YOU WERE ALWAYS LAZY, THE SLOTH INSIDE OF YOU HAD LONG CONSUMED YOU AND YOU DID NOTHING TO MAKE DIFFERENCE TOWARDS THIS ISSUE... SO WHY BOTHER TO STRUGGLE FOR YOUR LIFE NOW..?" Sans didn't even bother to continue struggling anymore, he fell limp in the eldritch god's grasp as more and more blood continued to leak from his wounds. "THAT'S WHAT I THOUGHT... NOW ALLOW ME TO PUT YOU OUT OF YOUR MISERY, I'M ALREADY SATISFIED FROM YOUR SUFFERING..." Asgore's multiple thousands of eyes would begin to glow in a rainbow glimmer, appearing to be charging up some kind of beam attack from them. It would appear that all hope had been lost for Sans trying to get out of this alive... in a last minute panic, Sans would use the remaining energy that he had left in him to summon a bone attack. This would come as great humour to Asgore. "OH, SILLY SKELETON... HAVEN'T YOU ALREADY GATHERED FROM MY APPEARANCE THAT I AM A NIGH-METAVERSAL DEITY..? HOW COULD YOU POSSIBLY CAUSE EVEN THE TINIEST OF PRICKS WITH YOUR MEANINGLESS BONE MAGIC..?" Sans would then allow his bone attack to fly off, hitting Asgore right in the middle of his gigantic soul, causing a crack to form right in the middle of it, clearly causing a great deal of pain to Asgore as hundreds of millions of human souls would begin to spew out from it, all very much to Sans' surprise. As more and more souls leaked from the eldritch monarch's soul crack, a great big white light would begin to shine from it...

The Aftermath
Once the light began to dim, Asgore could be seen clutching his chest, concerning amounts of blood leaking from it as well as drooling a bit of it out from his maw as well. Not even a few seconds later, Asgore would collapse onto his chest, now lying down on the chunk of what was left of his and Sans' universe. Sans, also in a fatal condition, though not nearly as much as Asgore was, would be seen standing in front of the dying boss monster. "Cough... hack... you... my soul... it wasn't stable enough... how... cough... how did I not have enough LOVE to kill something as weak and spineless as a lazy skeleton..?" Sans, quite very much angered by Asgore's constant remarks of him being lazy, would deliver a very forceful kick to the dying monarch's jaw, much like how his own brother did to him several years ago. "you... youve done nothing but harm towards me... dont you think you should at least fucking apologize..?!" Sans would shout at Asgore with what little might he had left as he continued to bleed out before summoning one last bone attack. "Ok, ok..! cough... I'm sorry... are you satisfied now..?" Asgore would ask, Sans would begin to chuckle as a result, squatting down to try and get his face in level with Asgore's face. "...no." The bone attack was swiftly lodged into the boss monster's skull, splattering his blood all over Sans' skull. Asgore's body would quickly fade into dust, Sans would, too, slowly dust away... ...until his dust suddenly started to float back towards him, essentially rebuilding what all had dusted away during that time. As it turns out, Sans had gained so much LOVE from killing Asgore that it literally saved his life, which, in question, had risen all the way up to 5.23534e+183! Sans' whole body began to gain a bright red glow to it, literally radiating with LOVE. As he tried to take some time to adjust to all of this LOVE, Sans would look up at all of the hundreds of billions of souls that Asgore had absorbed, floating aimlessly around the cosmos. "welp, looks like you kids have been put through enough shit. Time to send you all to your final resting place." Sans would say to the souls before summoning an ungodly amount of bones, all of which were spawned above each and every soul before being shot through them, shattering them all with ease. Once they had all shattered, Sans' LOVE would rise up once more all the way to Ω, absolute infinity... Afterwards, Sans would pick up Asgore's trident off of the ground before, with newfound nearly limitless power, he would teleport out of the ravaged Multiverse containing him, getting one last good look at it. "so, asgore said that all of you hated me, huh? well guess what, i'm better off without any of you, anyway. in fact, i'd probably be much better off without any living thing in existence! you hear that!? all of you fuckers are holding me back on my quest to finding inner peace once and for all!! you shitheads hate me so goddamn much? fine... ...T̵̤̆͌͝Ḧ̵̟̟̃E̵͎͕̳̯̰͛̑N̸͈͗͊̇̿ ̶̧̻͔̲͂Ą̷̃̽̾̓̉Ḽ̸̿L̸̛̞̓͋Ö̶̜̼́̂W̸̛̞̮̖̎ ̷̟̹̗͎͂̆M̵͙͇̼̖͉̓E̷̫̞̳̣͚͊̂͒̽͠ ̸̱͕̒͗̅͌T̷͕̫̦̉̇̓̈̓Ő̷̯̈́̑ͅ ̵̝̞̩̭̑R̷̨̛̯͎͐́̅͝E̴̘̣͇͂̌̆̄C̵̡̬̮̻͙͌I̴̩̣͖̺̳͊͋͋͐P̸̡̨̼̜̊͒̽͊͊R̶̫̹̔̌͗̕O̵̳̮͘C̸͍͗͌Á̸̡̛̪̝Ț̸̩́E̶̱̩̮̱̔͘ͅ ̸̢̢̝͉͋͌̊̇T̴̡͎̦̞͙͋̚H̸̛̰̥̹̉̒̽͝O̸̹͜͝S̷̡̯͓͗̍̿̓̈ͅÊ̷͔̾͐̕ ̴̢͖̥̬̮͂̅F̸͓̺͒̈̾̓͒ͅĘ̴̛̼̦͍̈́E̸̝̣̟̬͈̔̚Ļ̴͈̭͖̮̂̃͠͝Ȉ̸̭̇̌͛̚N̷͕͚̯̲̿̈́G̶̢̖̮̩̳̓̕Ŝ̷͚̔̂̈́͊ ̵̡͉̞̯̐͛B̴̧̄͌͂A̴̪͇͕̪̤̓̈́̔͠͝C̷̰̤͙̾K̵͎̠͓̍͂͝͝ ̶̢̹̯́͠T̸͔͛O̸̦̙̦̞͛̉͂͠W̴̡̳̯̮̄̽͂́̅A̸̪͒R̵̥̬͐D̴̳̲̲̠̕S̶̰̲̩̿͋̍̇͜͝ ̴͕̥͆͑̒̇Ạ̵͔͊̈́L̵͓̘̓̓̕̚͝L̵̛̘͖̞͕͊̀͂͊ ̵͖͖̥͍̄̾̽͠O̸͍̊̌͠F̷̨̬̞͓̥̚͝ ̴̯́͒̎͠Ŷ̸̢̌́̚Ő̵̧̲̣͖͓̀̽͒͊U̷̬͂̅͊̈́̅.̸̜͓͙̿̒͆̅͑ Was the last thing Sans said before he chucked Asgore's trident down at the ruins that was his Multiverse, once the trident made impact, the entire Multiverse began to form several millions of earthquake-esque cracks upon it before finally shattering into several billions of pieces, all floating outwards towards the rest of the Metaverse. The trident would fly right back into Sans' grasp, much like a boomerang. Now, unlike Asgore's plan to make the entire Metaverse treat him as a god, Sans was now aiming to completely destroy the entire Metaverse and, if he could, the Xenoverse in which the Metaverse and trillions of others were contained in...

Appearance
Before transforming into the Metademon that he is now, Sans would have worn a solid black zipped-up hoodie with light yellow-ish fluff around the hood, underneath the hoodie he would wear a yellow turtleneck sweater along with dark red pajama pants, his get-up being topped off with grey boots. His current get-up as a Metademon now isn't too much different from his previous get-up, only that he has completely ditched the jacket, his sweater is stained with blood and has three slash marks in them from where Asgore attacked him.

Hyper-Enhanced Bone and Gaster Blaster Attacks
This one is pretty self-explanatory, this is just the bone magic and Gaster Blaster magic, only that they've been buffed up enough from the incredibly immense amount of LOVE that Sans has to the point that they can easily make short work out of dozens of universes at a time. Using enough Gaster Blasters and/or bones on an entire Multiverse (Depending on the Multiverse's size and the color of said attacks, of course) could potentially shatter it to bits!

The Monarch's Trident
This ability is borrowed from Asgore, Sans can either swing it around or chuck it at his targets, it is potentially one of his most dangerous attacks as it was able to shatter his home Multiverse with a single chuck. Aiming it at a Universe will cause it to explode in a Hypernova, taking out several thousands of other universes along with it. Aiming it at people will completely erase them upon touch.

Yellow/Red Attacks
If Sans chooses to use yellow attacks, they won't be as powerful though they will travel at incredibly immense speeds, at around twice the speed of light! Though if he chooses to use red attacks, they will be much slower though the damage upon impact will increase by an incredible margin.

Absolute Infinite LOVE
Due to Sans having literally infinite LOVE, his HP has also increased all the way to infinity, meaning he cannot be killed by normal means. He must be either erased or corrupted back to his former state in order to truly die.

Teleportation/Multiversal Travel
Again, this ability is basically what it's name says, Sans is able to travel across Multiverse to Multiverse via teleportation.

Trivia

 * Animosity!Sans was one of the first Undertale AUs that I have ever made.
 * Animosity was greatly inspired by TheCh1knLord's Insanity!Sans.
 * Though Animosity focuses more on just destroying Multiverses, he will occasionally take the time to cause as much pain and suffering to the Asgores and Papyruses in the Universes that he chooses to specifically target as possible due to having bad memories of said characters.
 * He will even aim for other Sanses, potentially due to jealousy of them living a much better life than he did most of the time.
 * After the events of his backstory, Sans has only destroyed about two or three metaverses, each spanning up to around five to twenty years to destroy.
 * This, of course, is not counting all of the Multiverses within them.