This was requested by @LukessePhoenix.

And I messed it up...

Underfell

" Boss, please ! This isn't necessary ! " , Sans cried out for mercy, even if he knew that he shouldn't.

" See ? You're pathetic. I'm the only reason that you survived so long, but you're just a disapointment. You should be glad that I kept you around for so long ! " , Papyrus continued yelling at Sans, readying a sharpened bone attack.

" But Paps-I mean Boss..." , sadly, he wasn't allowed to call him brother anymore.

" No. You must die. " , and just like that, he stabbed his older brother, who started dusting immidiatly, since he had only one HP.

" Heh. Sorry Paps..." , Fell apoligized one last time as his soul shattered completly.

Undertale

A loud thud echoed through the ruins, and Toriel was quick to follow it. Suprised, she stopped in front of the golden flowers. Someone had fallen down, however, they didn't appear to be a human, but rather a skeleton. This suprised the caretaker of the ruins, had this monster survived the war ? Did the humans not know about this, presumably male, survivor ? How was that possible ? Was the poor guy injured ? It would be better to check the fallen one.

Name : Sans

Attack : 1

Defense : 1

HP : 0.0001 / 1

Lv : 0

Exp : 0

Fact : Has been mistreated, since he didn't fit in.

- Brother of Papyrus, but he's forced to call him ' Boss '

- Good friends with Ex-Queen Toriel

" After all, it's kill or be killed."

The former queen gasped at this, but she had to set priorities. This skeleton was badly injured, even if there were no physical wounds, and she had to heal him.

Weirdly enough, ' Sans' was way lighter than Toriel expected him to be, almost as if his bones were hollow. Did 'mistreated' involve starvation ? Trying to not hurt this strange monster any further, she carried him over to her home, placing him down on a bed. However, something caught the caretaker's attention as she placed down a cake for her patient. It was a knock, followed by a familiar voice.

" Old Lady ? Are you there ? " , it called out.

" Ah, Sans, you're early today..." , it was her funny visitor,...Sans...-Oh.

" Uh...No? It's the same time as every day ? Are you alright ? " , Sans was worried about the queen, from what he could tell, she was a really cheerful person, what could've caused this ?

" Sans...Listen, do you remember your promise to protect every human that comes through this door ? " , was it already time for Frisk to come ? Usually, it would take them a few days to return after a true reset.

" Yes...Has someone fallen down. " , Let's just hope that it's not another Genocide-route.

" Yes. But...They're not a human..." , Sans blinked in confusion, this had never happened before. What is going on ?

" They're not ? What else could they be ? " , now he was curious, which other options were there?

" He is a monster...A skeleton to be exact. And when I checked him, it said that his name is Sans, and that he's a friend of mine. But I can't recall meeting him..." , this concerned the original Sans greatly, how was this possible ?

" Could you make another promise ? Can you take care of this monster ? I would do it ,but, if I remember correctly, you claimed to be a skeleton, too. Would you do this for me ? "

This was a hard decision, it would be difficult to explain another skeleton popping out of nowhere, but what if he knew something about the resets ?

" Don't worry, I got your back, even if it'll be a skele-ton of work. I promise to take care of him. "

" Thank you, Sans. I'll go and see if he's alright, wait here, will you ? " , she walked away without waiting for an answer, trusting her friend without reassurance.

By now, the newcomer woke up, and he was currently staring at the pie, trying to figure out who made it, and if it's poisoned.

" You're already awake ? I didn't expect you to recover so quickly. Do you not like pie ? "

" QUEEN TORIEL ?! WHY ARE YOU HERE ?! AND WHERE IS HERE ?! "

" Do not worry, my child, you're safe now. A good friend will guide you, his name is Sans. I'm sure that you'll get along just fine, since your both skeletons. "

" I-what ? "

"Follow me. "

Confused, he decided that it would be better to follow the orders of his queen, even if she dressed weirdly. Finally, they reached a large purple door, and Toriel pushed it open, revealing snow and a lazily grinning skeleton in a blue jacket. Was this Sans ?

" Come on now, he won't bite. " , the former queen pushed him out, immidiatly closing the door behind him.

" Heya. I'm Sans. Sans the skeleton. " , he really was another skeleton, huh ? Not that he was doubting Tori, but this should have been impossible.

" WHAT THE HELL ?! ARE YOU INSANE ?! THAT'S MY NAME !" , first he woke up within the ruins, which had been closed of for years, and now there was a calmer copy of him with the same name ?!

" Nah, I was here first, so it's mine. But you fell down, so I'll call you Fell. Your welcome. " , this was getting ridiculous, I didn't fall down anywhere !

" WHA-NO. WHAT'S WRONG WITH YOU ?! " , a lot of things, Fell, way too many.

" Oh, geez, my ears are bleeding. Doesn't it hurt your lungs to scream like that ? " , with them having so many similiarities, a pun could be usefull to break the ice.

"... What ?" , what was this weird guy talking about ?

" It's a pun. "

" Oh....You like puns ? " , the fallen one decided to not question this any further, if the queen trusted this guy, he should, too.

" Yup. "

So they started telling each other skeleton jokes for a while, until Sans finally stopped at what appeared to be a sentry station of some sort.

" Wait...WHY ARE THERE EMPTY KETCHUP BOTTLES ? " , Fell yelled, as soon as he saw Sans' favourite drink.

" Oh, that's because it's mine. I love drinking the stuff. " , Sans stated, as if it was a normal thing to do.

" Eww, how could you do that ? It's way to sweet. " , that, and it looked way to similiar to human blood, and Fell had enough of that, even if he wasn't allowed to say it.

" Well, what else am I supposed to drink ? "

" Mustard. " , since mustard was yellow, it had the colour of justice, and justice was something that the red skeleton wanted for an eternity. Of course, he never told anyone about this, or they would have laughed even more. But...For some reason, he felt as if he could trust this guy. The way that the other was always smiling, yet being observant at the same time, it was as if 'Sans' could see his very soul, without checking him at all.

" Oh ? Why ? "

" It has the same colour as my favourite soul trait, justice. Justice is something that is needed, no matter the situation.Whether it's an innocent human, that is simply attacked because of the actions of other humans, or a monster who gets killed by his own kind, simply because it doesn't fit in. " , he had wanted to get this out for so long, and was eagerly waiting for a response, secretly hoping that it wouldn't involve more pain.

Sans' eyelights disappeared in suprise, he had never thought about it like that.

" You caught me of guard there. But let me ask you something : What would you do if a human killed your own family, and everyone you love, over and over again, and no matter what you do, they'll always beat you in the end ? "

" I would ask them if they were alright, not insane, but alright. Nobody acts like that without a reason, and it doesn't matter if it's a bad or a good one. Everybody needs someone to listen to them, especially the most broken people. So, I'd sit down, and ask them to tell me their story, and even if they kill me, I'd die happy, knowing that my last words were those that the human secretly wanted to hear. "

The original judge, who was able to read between the lines, found his hidden plea, and answered it. From then on, he fought for this strange skeleton, fought so he'd be accepted, fought for him to be loved.