Author's Note
Sorry again for the time taken on this. I don't have many opportunities to write. Still, I hope you enjoy!
Sans was no fool.
He was not ignorant to how Frisk had changed as time went on. The kid always came to the same spot every night, staring down a cliff for hours in the cold. Sans had noticed them one night while making his way to his patrol station, and from then, had noticed Frisk sitting in that spot several nights in a row.
Eventually, Sans found himself coming back night after night to watch them. He wasn't sure why exactly he had started doing this. Part of him was curious how long the kid would keep this up. Another part of him wanted to know what was going on in their head. Yet another part of him wondered which one of these days Frisk might end up 'falling off' that cliff edge.
And another part of him remembered the kid as a dirty, brother-killing murderer.
He was not ignorant to the way Frisk tampered with the flow of time. The first time he met the kid, they seemed alright. Scared and a little violent, but alright. His suspicions weren't aroused back then. He was aware of the disruptions in time, but he hadn't thought the child could be responsible.
However, the more he watched Frisk in their adventure through the underground, he started noticing patterns in the way time moved back and forth. Still, he thought there were more likely reasons.
Then the nightmare came. One moment, Frisk had struck Asgore down, the next, Sans was lying in his bed at home. Everything suddenly seemed so hazy. He got on with his usual routine, and when the kid stepped out of the ruins this time, they were covered in dust with a mixture of anger and emptiness on their face. They proceeded to bring ruin and panic to the entire kingdom.
The more Sans observed, the more he was sure of it. The way all the jumps in time seemed to revolve around them. This kid was responsible. It wasn't until Frisk was nearly to Asgore's throneroom that Sans decided to intervene.
"it's a nice day outside." He'd greeted. He was determined to stop the kid here. He may not be able to beat their ability to travel back in time, but he could sure as hell put a brick wall in their path forward.
The ensuing battle was long and brutal. Sans had crushed the kid many times now, but each time they came back, they made it a little closer to the end. Finally, Sans unleashed his special attack. He got cocky, and he paid for it.
"don't say i didn't warn you." He told them, as he felt his body splitting apart and disintegrating. Everything went black and silent for awhile.
And then he woke up in his bed again. He was dazed and confused. He didn't get much time for himself before his brother burst into his room, yelling at him about being a lazybones, and for a moment, he couldn't help but give a rare, genuine smile as he hugged Papyrus' leg.
The kid stepped out of the ruins once again, and this time, Sans was very wary. However, this time the kid came out scratched and mildly burned, eyes red and sore, presumably from crying. The only substances they were covered in were their own, and they wore the same face of emptiness that they had before, but none of the anger. Instead, it looked like a face of pain and regret.
Sans, however, still didn't trust them for a second. Not after they had practically committed genocide. Not after they had caused so much pain. But the longer the kid's adventure went on this time around, the more they showed their resolve to never hurt anybody, befriending everybody they could, Sans found himself doubting his feelings more and more. When the time came that Frisk succeeded in setting the whole underground free, he was able to give them a genuine smile for the first time in a long time.
But Frisk wasn't happy.
Sans was nothing if not perceptive. After the monsters were set free, he noticed that the time tampering had come to a complete stop. He figured the kid was happy, and he felt himself getting less tense as the days went on, finally able to relax both physically and mentally. But the first night he watched Frisk take a walk through the woods in the middle of the night, the first time he noticed those tired rings around their eyes, he knew they weren't happy. The longer they kept coming back here only helped Sans confirm it.
Sans shook his head, lost in thought as he was. Frisk had finally stood up and began their walk back home, as they did every night after staring for a few hours, and so Sans did the same. If the kid had any idea he was there, they didn't show it.
Returning to his home in Snowdin, he took his place on the Sans-shaped dent in the couch as his brother served up breakfast spaghetti, "THE MOST IMPORTANT SPAGHETTI OF THE DAY!", and dozed off as the morning hours rose, drifting between thoughts of Frisk and thoughts of nothing at all.
Papyrus burst through the front door, startling Sans awake. He was silent for a moment as he processed his thoughts.
"SANS, THERE'S SOMETHING WRONG WITH FRISK!" He said, turning to his shorter brother.
"there's something wrong with all of us, paps." Sans replied, lightheartedly.
"SANS! THIS IS SERIOUS!" Papyrus reprimanded, "FRISK IS HURTING PEOPLE!"
At this news, Sans arose. That couldn't be right, the kid had just put so much effort into making things right. He had to know what was going on.
"what are you talking about, bro?" He asked, trying to maintain a light air.
"CLEARLY THEY NEED MY HELP, SANS! I WILL GO TALK SOME SENSE INTO THEM!" Papyrus continued, out the door again without even registering what his brother had said.
Sans jumped to his feet. This could be really bad. He called after his brother, but Papyrus moved much too fast for him. He could only follow the trail of footprints leading into the distance.
Minutes of chasing footprints brought him to a clearing in the snow, icy fog in every direction. He could just make out the figures of Papyrus and Frisk. As he approached them, he noticed something odd. Had the kid's eyes always been so bright red? And that expression they wore. He couldn't grace it with a description, but it seemed strangely familiar.
Papyrus stood, calling out to Frisk, begging them to stop what they were doing, reminding them of all the friends they had made, but they seemed to ignore him entirely. Sans reached out, trying to stop Frisk with his magic, but it didn't seem to have any effect. He felt frozen in place and could only helplessly watch as his brother was cut down before his eyes.
As Papyrus turned to dust, Frisk turned to look at Sans and gave a devious smile...
Sans' eyes shot alight as he rose from the couch he had so lazily fallen asleep on. He slowly calmed down his heavy breathing as he collected his thoughts and took in his surroundings. Back at home again, but not back in his bed. That was good.
He wiped his hand down his face as he fully woke up. He heard clanging in the kitchen and spied Papyrus cooking bowls upon bowls of spaghetti. Sighing to himself, he let his head fall back down onto the couch, dozing off once again in thought.
"just a dream, right?"
