Okay. Okay. I wrote fic. I have this terrible problem for writing this sort of thing in any fandom I join- I BLAME MY FRIENDS FOR GETTING ME INTO THIS GAME UGH.
Anyway. I don't do puns very well, so sorry for the lack of them on Sans' behalf? Also, I usually headcanon selectively mute Frisk but that didn't suit the story that well. Ah well. Next time, I guess. :)

~Kitty

The monsters had built their town at the base of the mountain.

Frisk had been there at the time of building. They had helped carry things along from the houses in Snowdin and Waterfall and Hotland and nailed things into place and played with the other children when the adult monsters had been doing adult things. Sometimes, Undyne had picked them up and sat them on top of one of the roofs so they could see all of the valley. The building of New New Home- the king was still terrible at naming things- had been a process filled with laughter and tears and, really, it was a team effort. New Town was pretty much complete, six months along, although occasionally another monster would move in after hearing about the town.

Sans and Papyrus had built their house next to Alphys's lab, and it was almost entirely a replica of their house back in Snowdin. Small and cozy- and with a really nice garage, too! There was still a lone sock on the floor, and a sink that was far too tall for any normal person to use, and the two bedrooms on the second floor.

Frisk visited their house occasionally- they visited everyone's house- and Papyrus would sweep them up in a huge hug and exclaim "THE SMALL HUMAN IS BACK!" in his loud, carrying voice. And occasionally they'd make spaghetti together, while Sans popped in and out, plaguing their lives with incidental music and bad puns which actually weren't that plaguing or bad. Life was certainly never boring when the skeleton brothers were around.

That sort of thing only happened in the middle of the day, or the evening, though. Frisk had never visited the house on the corner of the street during the night- they had never had a reason to. So it was completely unexpected when a small knock at the door echoed throughout the house at five to nine on a Wednesday evening. It only took a few minutes for the door to open and the bone-white skull of Sans to peer out.

In the twilight blackness, Frisk nearly blended into the night and it took a second or two for Sans to spot the small human.

"hey, kid," he said, leaning against the doorframe. "what are you doing out here?" It was an hour or two past their bedtime, and Toriel most definitely wouldn't have let them out of the house they shared. They must have snuck out.

"Wanted to talk," Frisk said, with a pleading look. The cold night breeze ruffled their hair, making their fringe flop over their eyes. "Can I come in?"

Sans opened the door a bit wider, and they slipped in behind him, closing it with a click. "couldn't sleep, huh?"

They gave a noncommittal shrug, and sat down on the couch. They looked remarkably more pale than usual. Sans glanced up to the door of his brother's room, where great, rattling snores were echoing from. Papyrus was a heavy sleeper, and would probably nap through a nuclear explosion, given half the chance.

Sans returned their gaze to the kid, watching them carefully. After a moment, he spoke.

"you look bone-tired, buddy."

They managed a weak giggle and a smile at that, then sobered, staring at their hands.

"I'm sorry," they said softly.

Sans leaned back in his own chair. "i told you not to worry about almost burning down the house, didn't i? it was an accident. we all make mistakes."

The side of their mouth twitched. "Not that."

"then what?"

Frisk bit at their lip. "I've been doing terrible things," they confessed.

"as long as they don't stretch to murder," Sans began good-naturedly, then stopped at the look on the human's face. "oh. d'you want to talk about it?"

"I think so." Frisk took a deep breath, and exhaled. "You know how when I first met you, I knew what to expect? I mean, the whoopee cushion thing?"

Sans tilted his head; the best approximation of a raised eyebrow that he could make, but didn't say a word. Frisk took that as an affirmation to continue, and hurried on.

"I'd met you. Before that. I've been going back, every time after I got to the surface, because there was always something I got wrong- I didn't make friends with someone I should've, or I couldn't save someone, or-" They broke off, squeezing their eyes together tightly.

"or you killed someone," Sans said simply, no trace of emotion in his voice.

"Y-yeah."

"who?"

There was silence for a moment, the type that seemed to sweep the whole house and turn everything into a sort of bewildered ringing, but it was broken quickly by Papyrus's snores from upstairs.

"One time," said Frisk softly, their voice just on the edge of shaking, but not quite. "One time, I woke up at the beginning and I think I went mad, because I just kept killing everything and everyone that got in my way. It was like there was something in my head- something that was whispering at me- and every time I killed something, I forgot about saving people, and- well, I reset before I got to the end that time, so I don't think… anything… carried… over…"

"frisk."

"And then there was- something- at the end of it all- and it had you and Papyrus and Mom and Dad and Undyne and Alphys and it wouldn't let any of you go, but it killed you and so I killed the thing, and I shouldn't have, because it was- it was-"

"frisk-"

"Sans," said Frisk with utter seriousness, opening their eyes. "I killed Papyrus."

Silence.

Utter silence. More pressing and suffocating then before, and Sans wouldn't- couldn't- meet Frisk's eyes.

"I don't know what I was thinking," they said, trying to defend themself instinctively. "It was- I don't know- mad and insane, and I was just so sick of doing everything over and over, and the voice in my head, it was telling me-"

"kid, it's okay. that never happened."

"But it did!" they burst out, glaring at the wall as if it had personally offended them. "And then- and then you killed me- and I went back and killed you- and I can't believe you're still sitting here, talking to me, because I'm a horrible, horrible person…" They trailed off, staring at Sans, who stared right back, a blue flicker barely visible in his left eyesocket. It disappeared almost as soon as it was visible, leaving only a flash of light behind.

"Oh," said Frisk in a tiny voice. "You… you know, don't you?"

He inclined his head gravely. "yup."

"Oh," they said again. They considered their hands again, turning them over and over as if memorizing every crease and line in them, and slowly stood up, turning their back to the skeleton. They reached into their jacket pocket slowly, and took out the knife that Sans knew they carried around with them all the time, turning it over in their hands, before setting it down on the floor. It clinked as it contacted with a very final-sounding noise, and Frisk kicked it- all the way across the floor, so it tumbled into the kitchen and was lost underneath the fridge. Sans turned his head to watch it go, and when he looked back, Frisk was facing him again. Their head was bowed and their arms were hanging loosely at their sides.

"Get on with it, then," they said after a full minute of standing like that.

"get on with what?"

They slowly raised their head to look at him, and when their eyes finally met, there was a touch of incredulity. "Kill me. I deserve it, and I know you're capable of it. I know I'll only come back, but-"

"no."

"What do you mean-"

Sans sighed, turned, and walked into the kitchen, where he went to the cupboard. He began to rummage around, looking for something, and for a long time neither of them spoke.

"here's the thing about absolution," he said, finally finding a can of cocoa, and holding it up to the light. "you may think that it changes things. but death isn't the way out, because we both know that you'll just come back and ask me to kill you again."

Silence again, but a more comfortable silence, punctuated by the click of the electric kettle in the corner and the gentle rumble as it began to boil.

"I can't believe you don't hate me." Their soft voice was barely audible.

"sometimes i can't believe it either, " said Sans dryly, and re-emerged from the kitchen with a steaming mug in his hand. "cocoa?"

They eyed him, but made no move to take it.

"kid, if i really wanted to kill you, i'd have done it already. drink the cocoa."

Slowly, reluctantly; Frisk perched on the edge of the couch, and held out their hands, accepting the mug. Sans sat opposite them, folding his arms, and he watched as they drained it in a few gulps.

"I never wanted to be a hero," they said, wiping their mouth and dropping the empty mug onto the couch.

"i've never met a hero that wanted to," Sans said. "the people who want to be heroes the most are the ones worst suited to the job."

Frisk shrugged, and their gaze drifted up the stairs and towards the door of Papyrus's room which was practically rattling from the snores.

"you make a good hero, though," he added, skeletal grin (improbably) stretching just that little bit wider. "there's no one else i'd rather have my world saved by."

They muttered something that was only just imperceptible, but Sans heard. "stop that. you're a hero, kiddo, whether you like it or not."

"Then why do I feel like a monster?" The question was plaintive and seemed to fill the whole room.

Sans sat back, surprised by the question. "hey. i take offense to that, y'know," he said mildly, mostly as a cover to keep himself from reacting.

"You aren't a monster," Frisk replied instantly. "None of you are. I'm the only monster around here."

Sans shrugged. "suit yourself. but, y'know, i used to be a hero once."

Frisk peered suspiciously at him.

"don't look at me like that, kid. it's not that hard to believe. i know a thing or two about hero-ism."

"Yeah?" they asked, reluctantly interested. Sans spread his arms along the back of his chair, and crossed his legs.

"when you're a hero, you save people. simple as that. it's pretty much the definition of being a hero, right?"

Frisk nodded, with an oddly intense expression behind their eyes.

"every so often, there's a point when you have to make a choice who to save, though. and whatever you choose, there's someone who's not happy with that, but there's nothing you can do about it. the more heroic you get- the more people you save, the greater you become- the bigger the decisions become. eventually, you have to make the biggest choice of all, and the only right answer means that no one's happy. and suddenly…" he shrugged. "to everyone, especially yourself, you're the greatest monster of them all."

Frisk thought about that for a moment, and reluctantly nodded. "Does it get any better than this?"

"kid, i'd love to lie to you. but it really doesn't. the best you can do is try to cope."

Frisk's head dropped down to their chest, and they tucked their knees up, wrapping their arms around it. "I'm trying."

"so am i," replied Sans with calculated mournfulness. "it's harder than it looks, isn't it?"

Frisk smiled weakly, and choked out something that was almost certainly- maybe- a laugh. Just a small one, but it was still a success, on some level.

"think of it this way," Sans advised. "the king tried to do the right thing, but he ended up killing people to do it, right?"

Frisk made a small, reluctant noise in the back of their throat. "Right."

"was he a bad person?"

Frisk didn't even need to think about that. "Of course he wasn't-"

"then stop calling yourself one- if you're a monster, so is he."

"But-"

Sans forestalled them with something that was maybe a glare. "angst gets you nowhere, bucko. take it from someone who knows."

Frisk tugged their jacket around themself. Upstairs, the snoring continued.

"What do I do now?" they asked.

"carry on. it's all you can ever do." A pause. "it's all anyone can ever do."

"Okay," said Frisk, which seemed like a bit of an understatement considering the deeply philosophical and meaningful things Sans had just said to them. They scratched their ear and looked pensive. "Sans?"

"yeah, kid?"

They looked almost embarrassed. "…could I have some more hot chocolate? I didn't really taste the first mug… and…"

Sans chuckled, and rose from his seat, ruffling Frisk's hair. "sure thing. anything for a hero."

And this time, he noticed (as he entered the small kitchen once more), they didn't protest about the label.

The End