It was a beautiful day outside. Birds were singing, flowers were blooming... On days like these... Sans needed to rest.

His brother, his friends, every single monster in the underground had died by one human's hands. Barely fifteen years old, yet this child had managed to make the greatest warriors of the underground break into dust with a single hit. He knew he would not be enough to truly stop them, if they were as determined as he imagined. For once, the knowledge that his efforts would be fruitless did not stop him.

It was such a hollowing sensation to realize the person you promised to protect had gone around, slaughtering everything in their path, even San's own brother. Oh there were monsters left, no doubt. Alphys was smart, and Mettaton had meant to buy time with that secondary form, not win. Whether there were enough for the Monster race to survive... that was another matter entirely, but he had no opinion on the matter. What mattered now was that this human died.

Perhaps it was fate, or some twisted sense of curiosity, that drove the human this far. He was curious about their reasoning. Surely it could not have been so harrowing a journey that they turned to bloodshed immediately? He had stopped watching after Papyrus died, still believing in the human. Odd, then, that Papyrus was the only death they cried at. After that... it seemed the child stopped existing, replaced by a machine bringing only pain and death to anything in its way.

Sans could have done more, he knew. He could have convinced Asgore to let him absorb the human souls, he could have done it without Asgore knowing. That would not work. Humans, even when one of hatred was involved, stuck together. It was a twisted sentimentality he would never understand. Justice stood above all else. Mercy was important, but in this case... he had lost that option.

Even if the human had just killed Papyrus, Sans would not have attacked. He would have hated the human, desired their death, but not acted upon it. Now, with the majority of the Monsters dead at their hands? He had no intention of anything but killing the human. Perhaps he was just using those deaths as an excuse to extract a more personal revenge onto the human, but it did not matter anymore. He fully intended to die.

How else could he be reunited with Papyrus?

The human was approaching. Sans never learned whether the human was male or female, and did not care. Sans had scarcely seen humans, so he would not really notice the differences between males and females of the younger ages. It did not matter. The human could identify as a toaster and Sans still would have not cared. That was not what any of this was ever about.

The human smiled, a sick, cruel facsimile of the common expression of joy. Those red eyes... Possession? He knew it was possible, or at least theorized it. Human souls were mostly unknown, and a few of the other humans were just as cruel as the human had shown themselves to be. Still, it did not matter, he had no way to undo whatever happened. Only the human had that power.

"heya." Sans spoke calmly, his incomprehensible rage being only slightly hidden beneath that calm exterior. "you've been busy, huh?"

The human stepped forward, red eyes staring into Sans' white eyes.

"heh. so i've got a question for ya. do you think even the worst person can change? that everybody can be a good person, if they just try?"

Another step. Was it bad that he was looking forward to this?

"Heh heh heh he... well here is a better question. DO YOU WANNA HAVE A BAD TIME? cause if you take another step forward, you are REALLY not going to like what happens next."

The human paused, as if considering their actions. Sans was a bit annoyed at this, but allowed them to consider themselves for a moment. That look on their face... They really were a freak...

"You know." The human finally spoke, the irritatingly calm and soothing voice echoing in the hall. "I have heard that speech so many times... It never gets old!"

"what are ya talking about kid?" Sans questioned, feeling something... wrong.

"Oh, no, please, keep talking about how I must deal with the consequences of my actions, I do so enjoy hypocritical speeches." Their smirk widened, which Sans reasoned should not have been possible.

"kid, if you cannot face the consequences of your actions, then ya shouldn't have done them." Sans glared at him, nothing but hatred for the human left.

"Oh yes! You are so correct. So then... Why do you think I am here?" The human tilted their head, an inhuman giggle coming forth.

"curiosity? anger? fear? too many possibilities kid. it doesn't matter though, you did too much, you took one step too far."

"Rage." The human stopped grinning, their head turning back into a neutral position, glaring directly into Sans' eyes.

"rage? about what? how we welcome you with open arms? how we tried to forgive you for murdering everyone? HOW YOU KILLED MY BROTHER?" Sans rage was reaching new heights, though he could not help the cold pit forming in his stomach.

"I was ten when I first fell into the Underground." The human spoke calmly, not even blinking.

"Toriel kept you in those ruins for five years? huh. so what?" Sans had to wonder what exactly caused this. Toriel had not mentioned a human falling, and she would have, given the situation...

"No. You know of the Resets. Well, do you know of Loads? Of course you do, you just know EVERYTHING, don't you? Always hiding secrets, always talking in riddles. This is the only point in time you have ever really opened up more than an ounce, just enough to be the cool mysterious guy seemingly helping out." The human smiled again, a small confident one, rather than the malicious sadistic one from before, though somehow this only made Sans feel worse. "Loads sometimes do not change your age. If you age a day, then load the previous day, your body will still be a day older. It is a bit random in when it happens, but it is not uncommon. Interesting is it not?"

"No... NO!" Sans roared in defiance, knowing exactly what the human was implying. "you have to be lying!"

"Oh no, not at all. Toriel never meant to kill me, it was always an accident. The other monsters in the ruins... they meant it. Those on the way to snowdin? They either meant it, or were too ignorant to understand what they did. Papyrus?"

"He would never kill you!" Sans interrupted, defending his deceased brother.

"He never did." The human paused, a wistful smile forming. "I really liked him. But all those beatings. All those times I came close to death, in the freezing cold, only to be thrown into a cage, regardless of how easy it was to escape. His was the only death I really did not want to do, but... well, you know all about justice, don't you?" Sans felt the weight of all the Underground's sins crawling on his back. "Yes, exactly. Undyne? Hah! One hundred thirty seven. That is how many times she killed me. A trained warrior like that, stronger than most physically strong humans, fighting a child? What did anyone expect to happen? I have no magic, no real weapon. The best I have ever gotten is a dagger. Oh she gave me a spear to 'make it fair', but... I was a child. Mettaton? A robot who killed me many times, some accidents, some on purpose, and some were better left unsaid. Bombs, fire, lasers, mercenaries, kicks, so many deaths... Then we get to Asgore. I liked him, as much as Toriel, really. He wanted to lose. I think of all those in the underground, perhaps he had the best reasons. Sure, he made a lot of idiotic moves, but he was the one who had to live with his choices, and he lived in such misery for it! That is justice. Still... he killed me two hundred times, at least. At some point, I stopped counting. Do you know how many deaths in total, Sans?"

"And how many did you kill?" Sans knew he was in the wrong, but he stopped caring a long time ago.

"One hundred twenty two." The human's face once again changed into an utterly neutral expression.

"That is a lie! If you truly lived so many lives, you would have killed many more than that." Sans spoke out again, knowing the human was leading him, but too infuriated to care. Or perhaps, not infuriated, but... in denial?

"Ah, you are not wrong. But you see... the difference is, they forget about it. I bring them back each time. I cried because of them. I felt terrible. You? Undyne? Those random monsters? You all celebrated my deaths. Over and over. Not a single hint of remorse. Well, Toriel and Asgore had remorse, but they still went through with it. Those two, at least, I can respect. I will admit, you only fight me on this exact path, where everyone else dies, but... what about that promise, Sans?" Sans felt his body freeze, recognition dawning in his eyes. "Oh yes, when I am less violent, particularly when Papyrus survives, you tell me all about it, right before threatening me. How you promise Toriel to protect me. Quite... interesting. So, in this hall where you always judge me, let me ask you this... Where were you, when I died all those times? Had you really protected me... none of this would have happened."

Sans fell to his knees, the events of the week being too much, particularly with that last sentence. It was his fault, and he knew it. He thought the kid would be fine, since they had the power of Reset and Save/Load, but... he forgot that the kid would still FEEL everything. All that pain, frustration, suffering... He choked back a sob, apologizing internally to everything that the human had killed. It was his fault... just like before. He just wanted to die, to be with them now, even if he knew he was probably destined for somewhere else... "Kill me."

"What was that?" The human smiled condescendingly, as if mocking his internal hatred. All that hatred once directed towards the human, now turned inward.

"KILL ME! You can have your justice, your revenge, that's fine! Just... end it." Sans sobbed, the pain of losing... causing his brother's death too much to bear. His only reason for living, and now even revenge was gone.

"No." The human chuckled. "That is your punishment. Everyone else died. You? You live with that." Sans looked up, the earlier rage slowly coming back, even if his desire to just die was too much to bear now. "Oh don't worry. I'll reset soon enough. I'd say... five years. Funny, isn't it? A True Reset will bring me back to... this age, I believe. So, five years of my life wasted by all you monsters, five years of your own lives gone."

"No one will remember."

"Oh, quite incorrect. You see, this is not the first time I have killed everyone. The first time... oh I could not bear the pain of doing it, I was just so angry and scared. I had so much power, what was I going to do with it but finally break free of this nightmare? But... then I met someone who changed my mind. I was so focused on escaping my own pain, I did not realize I should do quite the opposite. You all... All of you monsters caused me so many deaths, so much pain... You wasted five years of my life, so I decided to take away five years of yours. Everyone but you gets five years of being dead. You? You get five years of everyone else being dead, while knowing just one act of kindness, one act of mercy could have prevented it all. The best part? My partner's deal means none of you will forget this. When I true reset, I will leave this timeline forever, probably just for another Frisk to come. I pray, for your sake, you learn from this. I might even be the merciful one among all of us."

Ah... so their name was Frisk. And this... was mercy?

"I could have done so much worse. I could have just kept you all in jars, unable to speak, experience the world, move, anything but sit and THINK. Can you imagine that? You would all be insane within days. I am not sure if I could keep going after that. You all? Hah! Good luck. So yes, this is my mercy to you. I wonder how you would have done in my shoes, Sans. But then, we both already know, don't we? You would have just given up."

Sans did not even realize the human was already leaving the room, too focused on his fractured emotions to care.

"Well, I am also giving you a chance I suppose. I wanted you all to learn, after all, not just punish you. So... try to treat the next Frisk better, alright? Maybe they won't be the monster that you made me into."

And so, the human left Sans, broken and dead inside, a shell of the shell he once was.

"You lied." The spirit spoke, its voice containing an echo-like quality to it.

"Only in that I did not explain my other reasoning. Are you sure you are okay with what we are going to do?"

"You forget, I experience everything you do, just not as... intensely." The spirit laughed, which may have been merry, were it not for the cruel smirk grafted onto its face.

"Maybe, but Sans did not need to know that I needed the human souls. That YOU needed the human souls."

"Well, you did want a partner with you forever. And I wanted a body to make sure we are always together. Linked by soul and by body? Doesn't that just sound so... interesting?"

"It does, actually. Though... when we first met, you acted much different. Why the change?"

"I had thought you only sought power, so I accepted that as my purpose. But, when you revealed your truest self to me... I changed my mind. I had already gained individuality, but we both wanted the same thing. Mercy, Justice, Hope, Love, Family... but there was something more than that."

"What was it then? I have power, I can destroy this timeline myself now, and you can destroy the entire multiverse if you please. I do not believe I have ever cared much about what others thought of me, so fame is also out..." The human child spoke, slowly walking towards Asgore.

"We both wanted to protect you." The spirit smiled, much more genuine than anything either had shown before, only for a similar expression to be returned by the human child.

"Well, you are the only one I care for anymore. I may like some of the Monsters, but they... do not understand what it means to truly die, over and over. Toriel is adorable with her motherly attitude. Asgore with his amazing remorseful king status... Papyrus, being as goofy but awesome as he is."

"Don't forget Undyne. She was always amazing, more than anything. A true Heroine! Pulling herself back together with raw determination..."

"Mettaton was goofy, but in a great way, I always appreciate large hams. Alphys reminded me of myself as a child too, just... with actual problems hidden in that lab of hers."

"I actually think Sans was my favorite. Always mysterious and powerful, lazy but always more than meets the eye to him." The spirit giggled.

"Don't forget the SCIENCE!" The human posed dramatically, pausing in his slow walk towards the Throne room, causing the spirit to giggle more. "But they have to learn. This could not keep going on. I have been in this timeline so long and no one remembers except Flowey, and he was his own problem... Sure you don't feel bad about what we did to him?"

"As much as I still love Asriel, no. That flower killed you many times, and I felt each of them. That it was the creation caused by my failures with Asriel only makes me hate it more... But still, it is amazing how you managed to find weedkiller in the underground, especially since he popped up right into it."

"I figured irony was more important than anything in that. In all fairness, he deserved death, but without a soul, can you really blame him?" The human child shrugged, the question flowing from them without real thought.

"Hey! I don't have a soul either!" The spirit seemed to pout at this.

The human smiled as they finally reached the thrown room. "You have mine, and you always will." And soon, Chara would have six more as well, for a human could not absorb another human soul, but a soulless being could absorb any type of soul.

A/N: I always felt people took the Genocide route in the wrong way. Instead of this kid just straight up going crazy or being possessed and killing everyone, what if they had been broken down by so many deaths, so much pain, and no one ever helping them out? It would be tough to explain Papyrus, but everyone else really kind of deserves what they get, if the same morality is applied to them as it is to the player. This is what happens when we remove the player from the equation, though. Instead, its just an angry kid who spent FIVE years of their life being killed over and over, only to be scolded when they kill a single thing that attacked them in the first place.

Also, for all those who love AUs and fanfictions, or Alternative Character Interpretations, good news! Undertale, according to Sans' dialogue and Chara's Genocide ending speech, supports the Multiverse concept, which means ALL possibilities for Undertale are true simultaneously... unless it operates on a contained Multiverse concept, but that is less likely. So yeah. Chara is a boy, girl, dog, transgender, blind, whatever. All of them, because each player has their own interpretation of what Chara and Frisk are, that becomes true. Which is likely what Toby intended, seeing as Frisk was basically made to be a player-insert protagonist.