All of them did it, from time to time.

The active portal Nightmare had left in a neglected basement room of his castle, uncommented on until asked. It appeared to shift slowly between a few different worlds, barely differing views of the same mundane wall of cave. Dust had assumed other current servants of Nightmare had done as he eventually did, and received the same finality in the answer spoken by their leader.

"That is… not, off limits to you." Dust had waited patiently for Nightmare to continue, listening to cold amusement creeping into a deceptively silky, warm voice; "But you may regret using it. The fun might even sour to Killer after a while, and I would advise against broaching the subject at all to Horror.

… Most would prefer to leave it forgotten, after a while."

Standing that day returned to the agonising silence echoing a hundred voices of his own timeline, Dust understood, and left it behind once again, thinking never to return.

And yet, from time to time he found himself stood beyond the portal. To listen to old friends perhaps. Listen to old voices change from encouragement of his actions in killing them, to questioning and condemnation of him abandoning them. His world. Maybe he was punishing himself.

Each visit, the piles of dust seemed to shift and be in slightly different places, So. The anomaly had continued even without him to challenge them. Did they want to get him too? Well, tough luck kiddo. Being there hadn't been enough to stop them, only trying again and again as each vied to get the upper hand. It only prevented the corruption of the soul of the fallen child to hopeless apathy to end the world around them. Not being there turned out to be just enough to stop this culminating anyway.

He was surprised a few times by the occasional monster walking around unhurt, almost randomly. Talking to the jarringly more gentle versions of the monsters to those he had got accustomed to in his head was like waking up from a dream you felt was real, only to discover on waking how off it had been. They spoke to him about the news of a human in the underground, and everyone wondering where Sans had been all day. He left again, and a pile of dust was to be found in the same place on his next visit.

Maybe he was careless on purpose. He never wanted to let the kid encounter him again. Let them feel the loss of a connection to someone who knew them, even as an enemy. But there they were one day when he short-cut down from where the portal was. There was no dust on them, and the two stared at each other wordlessly, until Sans scowled and walked away to leave them standing there. He simply left once again.

If he thought it would hurt to visit his mostly dead world each time, Dust didn't expect the pain when he started to only encounter a fully living Underground. Over and over. He walked away each time, returning home to Nightmare's castle and refusing to let the kid bait him. That's what it was, right?

Did he dare believe it? He tried to forget but couldn't take not knowing. So, facing the child again one day, he challenged them. None of the old pleas to give up their genocide. "what's the game kid? what do you even want now? dangle our lives in front of us before you go back for the kill again? got bored? what."

He barked a laugh out loud when they said they wanted to free all the monsters and let the world go on. To finally 'complete' things. He would NEVER believe that. He made it clear it was only for amusement of watching them fail that he indulged in the dumb pretence. Just this one last time, he said, and he wasn't ever gonna come back to this place, that was a promise.

Dust stood on the overlook under the rays of the setting sun, stars on the horizon. Heh, it was nice to pretend, not that he was gonna let the kid know that. He said all the things he remembered saying in those times long ago when the kid had bought them through fairly peacefully at first. Even keeping up the act to the kid. He nearly forgot himself at one point talking to his real brother, pulling up his hood out of habit to brood behind, before it was yanked back down by a curious Papyrus to ask him WHAT he had done to his eye he was hiding. Dust brushed it off easily, using his practice at being an imposter when under orders. He was an imposter even in his own world.

"so, this was nice," he sneered as he stood to the side with Frisk while the other monsters tragically enjoyed their new life under the sun and stars. "but let's not fool ourselves here. neither of us are who we're pretending to be and we both know you aren't capable of not fucking it all up even if maybe you want to, whoever you really are. so it's time to go kid. you get to keep my old home to rot in until you have to suck it up and live with one of the crappy timelines where at least any monsters left alive are free of you, heh"

The child stepped up to him and stared for a lengthening moment. And for a moment, just a moment, Sans saw lines in the air like an interface, with 'ACT' shimmer in and out of existence like a trick of the light. Several sets of words were there, and they turned their gaze to the first ones, "Destroy files". It lit up, before vanishing. Then the kid seemed to stand there, blinking in confusion for a few minutes. And that's when Sans realised this wasn't the same person, just the one left behind who was called Frisk. They seemed to come back to themselves, smiling innocently and wandering off to speak to the others. Planning to stay with Toriel. His brother got excited and started to race down the mountain.

Wait.

This was. This was… no! It couldn't be for real right? He was… he… oh shit he couldn't leave now. His friends, his family. The human?

He still had all the LOVE he had gained, still had his level of violence. His memories hadn't been reset since he had become aware of it all and made that terrible choice long ago, to kill enough monsters before the kid could get to them all that time ago. How did he even fit in here anymore? To keep pretending he was good?

Dust casually walked to go back into the underground, numb inside.

He came face to face with the flower. Flowey the flower. "Howdy!... Uh, well, this is unexpected."

"flowey. the flower my bro always talked about but i could never find" said Sans. "asriel. heh, guessin' me knowing that might surprise you too… heard stories from elsewhere"

Flowey paused, and scrutinised him, before scowling to the side and turning back to continue softly. "Elsewhere, huh? I've been wanting to ask you; how in the heck do you have that LV, trash-bag? You didn't have it before today did you? Why do I sense that you have killed a bunch of the monsters alive around us right now?...

…Are you done, even?... I've been watching you as Frisk made their way through the Underground. I know they've killed too and undone it, but kinda weird; they seem different, like they are themselves now and it wont change again. But not you. Why? I… I hoped this was over and we had finally broken free." The flower's head dropped a little. He looked up at Dust sincerely.

Dust reached back to grab his hood, then thought better of it and rubbed the back of his neck before dropping the arm again. He honestly didn't know. He could just carry on walking and short-cut back to the portal, right? Everyone who cared about the old Sans would miss him, but they would also be rid of the person he was now. He didn't deserve this after all he had done.

"i dunno bud," he started. "i think it'll be best if i just disappear, right? i got places to go. they… they can all have a good life without me." He paused. It was more than he ever wanted to confess but someone from his home should know the truth, and knowing what he had learned about Asriel, he seemed the right one to leave it with.

"i was tryin' to stop them killing everyone, the kid. they were a different sort of determined. one day i just started remembering fully all the past timelines. yeah, I know about those… and i realised the kid, the anomaly wasn't stopping. everything was gonna just end so i thought i could beat them and make it stop. but they still never did. 'til now."

"just never thought i wouldn't get reset back too, somehow." He wanted to hang his head, but made do with turning his skull and cupping a hand over one side.

Flowey's form shifted and changed shape. Asriel stood there. He smiled weakly. "Huh. That's the truth, isn't it? Not much point hiding from you then. I guess I cant really argue against you wanting to disappear. I'm, gonna do something like that and I don't know how long for. I have a little time left able to hold my old form at least so I can go back. I have… memories, like you do too, but in my case it wasn't to try to save everyone in a, ha, really roundabout way. That's what you were doing, Sans…

I have to face who I am now. Maybe you do too?" Dust didn't respond. Asriel shrugged his little shoulders, "If I'm capable of being a better person, maybe you have the same chance? Also knowing Papyrus, I think your brother is about to go barrelling headfirst into the humans out there if you don't cut ahead to say hi first. You do have places to be, you know."

It was two months before they found him.

He was working one of his jobs. Not the highest career he could have found but more humble, maybe out of a sense of penance. He had once long ago imagined working at a university or in the sciences. Maybe in future, but for now he was, you know, he could say happy.

The ghosts he used to talk to still visited him now and again; his illusions weren't going to completely go away just like that but it was getting better. It was a challenge at times finding himself having to make imaginative excuses when responding to the angry ghost of Toriel's voice, only for it to slink away as the shameful pretender it was when the real Toriel swept happily into the room. Pap's ghost had ended up quieter and quieter, as his real brother had seemed to up his exuberant entrances. Papyrus had a knack of talking over it, if the ghostly version ever tried to say anything in his presence, as if he could tell. It couldn't compete.

Dust finished making his current burger to his satisfaction and was ready to hand over the food to the next customer, so stepped across from covering his colleague's break in the prep area. He looked up from under the brim of his uniform hat to address the human or monster who would be waiting and froze. Killer was standing there with a devious grin on his face. So this was it then. Someone like him does not get to have a happy ending.

Dust didn't speak. He tensed, waiting for Killer to start the inevitable violence. Killer looked amused. "you knoooww I think I'm gonna add to my order", he drew out. "the chicken supreme is great, but gonna add a side of fries and milkshake too. vanilla." Dust didn't react.

"oh and you're already familiar with his usual, but mega meal with all the sides too. please." Killer beamed. From behind a group of humans another skeleton stepped out. Horror. Unlike Killer, he was dressed in a different set of every day clothes from his usual, as if blending among the humans like any other newly arrived monster, a hoody obscuring his skull injury and face.

Dust placed down the order and spoke. "so you assholes finally found me, and the boss sent you to…? drag me back? or is leaving a betrayal and i'm marked for death now?"

"awww, we just thought we'll see where you've got to that's worth ditching all of us. what's so special about your old timeline. it's the same as any one of those now the barrier's broken, but you're not coming back?"

As the sounds of his colleague back working in the kitchen filled the space, Dust wasn't sure what made him decide to fight, but he knew he was going to now be on the wrong side to his old allies. He was prepared to die alongside his world.

"what's wrong buddy?" Horror came and leaned on the counter beside Killer, who has fished out the change to pay with and placed it down for Dust to reach. "service a little slow round here? we just came for lunch."

They still weren't attacking yet. Dust didn't know what to do so stuck his head towards the kitchen to call out the extra order that they had made, turning his head but not his eyes lights, which stayed watching his old friends, waiting for the coming fight whenever they got bored of the game they were playing.

The two sat down to eat, grinning and waving to him from time to time but they didn't start anything the whole while. They finished eating and went to leave, weaving past the wandering human patrons.

Unnerved by this law abiding behaviour, Dust called over to his co-worker to cover him, saying it was an emergency. They weren't too happy he appeared to be bunking off to go with his friends, but accepted when he offered to pay them back three-fold in covering shifts.

A little delayed by this bargaining, he skidded out of the door to follow the two. It was all it took for them to lose him. He spent the rest of the day chasing around town after shadows and looking for any blood, dust and destruction which was not evident. It was by luck someone sighted them when they returned to the underground later in the day. The phone call and the concerned voice of Asgore asking if anything was wrong, since he was there digging up some plants to take down the mountain and 'Sans' had gone right past him back into the underground without a word. Dust played this off by just saying in a casually warm tone of voice that he got distracted rushing back to find something he left in the old house.

They weren't in this underground, so they had gone back through the portal to the castle... He went home to Ebott, but didn't sleep that night.

The next day, he got up from a still made bed and opened the curtains at the sound of a crash. Outside he had been working on building a small summerhouse for the garden. On the ruins of this now lounged Killer, and Horror was making himself at home in a garden chair with a glass of juice.

Dust decided to bring this to a head once and for all and went outside to confront them . But when he got outside they were both gone. What was their game? He knew there was no point going to the guard or the human police, and it was too risky to even warn family and friends, in case they wanted to get involved. So he had little choice but wait to see what was next from his old allies.

The next trouble came when his boss at the car wash called him happily into the office. They had already been short of workers so Dust got this second job thanks to the companies poor advertising leaving the new monster the only option. Over time he had proven himself so this day when the boss called him over, it was to ask him to interview a potential new employee.

Dust was ready for this bastard. There hadn't been any new employees due to come in, as no one had expressed interest to the current flyer pasted outside the door yet. So when the door opened to the office and the supposed interviewee came in, Dust turned to round on the new entrant with all his rage.

"what do you think you're fucking doing?"

It was not Killer or Horror. It was a very terrified, nervous looking human who looked to be about the right sort of age range to be applying for this sort of job as a bright new starter to the workforce. Dust sagged and started to splutter, about to de-escalate with some swift excuses and apologies, when from behind the new interviewee the door pushed further open, and yes, Killer walked in. He had a knife to the poor guys back. Dust was almost thankful it wasn't because of his abysmal interview skills after all.

"gotcha", smirked Killer.

Dust now had a human hostage situation on his hands apparently. But luckily for him as Horror ambled in he irritably told the guy to scoot. The teen did so pretty promptly and promised not to speak about this incident. Sure about that, but Dust decided he could hunt down the guy and befriend him later to be safe. Be his personal benefactor and advocate for getting a much better start in the workplace in a nice office or something.

Killer and Horror sat down in the chairs facing the desk as if they were coming for the interview. They confirmed this was today's game thanks to Horror speaking up with, "we're here for the interview" and slapping the flyer on the desk. He leant back in his chair with a challenging expression.

"i'm not going to interview you assholes", said Dust, incredulously.

"what?" Killer shot back. "don't you want some wonderful new employees? we're here to turn over a new leaf like you are."

"you're really not expecting to make me do an actual interview are you?" said Dust.

Killer had actually only intended to wander back off of this point, but he found himself quite enjoying pretending to be very well behaved and innocent. His exposed, corrupted soul hadn't even butt in for a good mindless rampage yet for some reason either. It felt… calm. So he instead said to Dust, "hey why not? job's good enough for you Dusty, maybe we could all be work buddies again, i can clean up nicely, hehehe"

Dust muttered "are you freaking kidding me…"

Killer cupped his closed hands on the desk in a polite sort of pose and continued as if he had in fact been welcomed. "i have quite a few skills! i'm very quick at …'jobs', ruthlessly efficient and very people orientated. got a skeleton of Experience. not been into car washing yet but I think you'll find me quite eager to give it a stab" He looked towards Horror but the guy wasn't playing so much as looking more genuinely pissed off. Killer on the other hand was having fun.

Dust tried the question one more time; "did the boss send you?"

As if matters couldn't get any worse his current boss had overheard that and was stepping in the door. "Yes! I did and I don't know if you are already acquainted from the Underground as I've heard it was pretty close knit, but we've got both of these gents interested so I think we can make positions for everyone, assuming they pass the interview!" As the car wash owner gestured warmly to the pair, Killer seem to be doing his best attempt at big empty Bambi eyes in his show of good behaviour, and Horror just leaned back in his chair more comfortably and frowned straight ahead.

"Well I'll leave you to it, and if you need if you guys need anything I'll be in the reception and forecourt. Good luck guys!" He stepped back out and Dusts eyelights fell back to the two.

"bye boss!" sang back Killer.

Dust gave up. He thought, it's not like I'm going to get rid of them so easily. So he decided what the heck, and ended up spending the better part of his morning on giving a surreal job interview with one saint of an applicant, and one who stubbornly gave one word answers. But he did give answers. About life skills and car washing anyway. After they left Dust didn't even bother to follow them, just awaiting whatever they were up to next. He wondered how long it would take before Nightmare came looking for him, or if he wasn't aware of them following through the portal set to his world.

Dust was almost getting used to the visits even if he couldn't let his guard down. He did his best to mostly ignore the unhelpful occupants of the trolley he pushed around while shopping. He was actually pretty proud of his improvising skills at bullshitting a story about historical weaponry, following an at the time extremely stressful show-and-tell event at Frisks school that week, with a teacher watching their lot of 6 year olds worryingly enamoured by the knives, axes, and a fake, yes-it's-a-replica-but-don't-touch-that bazooka Horror and Killer had bought and laid out on a table in front of the class. It was a few days after Dust got a very diplomatic letter banning him from the school when Nightmare did turn up.

He wasn't that surprised to see Killer and Horror openly approaching one day, when that sea of black rose behind them, seemingly from nowhere, angry and foreboding. What did surprise him was that the entrance of their master surprised Killer and Horror, by the way they stared down at the shadow shooting forward to engulf their feet as it fell on them from behind. They comically looked at each other, then turned in sync to look back and up.

Like a harbinger of doom, Nightmare loomed over everyone stood out in Dust's sleepy suburban street. It was just luck that no one else was around today so far. Not that it would matter to try to cover anything up if the God of Negativity did decide to take interest in this world.

He spoke through the dark sludge, "I do not employ you to run off and play games. You are needed at the castle. Return. Now."

Dust had already made his decision and stood his ground to face his fate. "i'm not coming back."

To which Nightmare replied, "Was I asking you?"

Nightmare wasn't there for him.

As the wave fell down and further took form, it was revealed he was there for his wayward underlings. And this no longer included Dust.

Killer started to protest that Dust had betrayed them by abandoning them, and Horror looked torn between obedience of Nightmare and defiance of his old comrade.

Nightmare looked over the three of them. "Did none of you consider why I keep that portal there?"

Dust responded "kind of thought it might be a trap. leave the bait of freedom to walk away, and punish us when we take it. is that what this is?" He asked resignedly.

Nightmares dark tentacles flicked with mild impatience as he observed their faces and noted, "No. Do you think this is the first time this has happened?"

This left all three of them confused. Horror, jolting slightly as if feeling a pang of pain in beginning to understand, broke his silence to ask, "what… do you mean…?"

Nightmare looked over each of them. "I leave that portal for a purpose. It is not the first time this has happened as I said. You are not the first to work for me. I expect full loyalty from those who I employ. But," he paused, "for all who serve me of their own volition, I have opted in perhaps misguided consideration to leave a way open if they ever want to leave. Consider it… acceptance of things being possible to change."

He turned to stare distantly for a moment to add, as if for his own sake; "With all that entails."

He added "Although this does not often happen." and looked towards Horror. To Killer and Dust's surprise Horror looked down, dejected. "Many who try the portal prefer to leave it forgotten again." finished Nightmare.

Killer and Dust realised why Horror was so angry at all this. He must have tried to undo the suffering in his own Underground and found no way through. And here Dust was, in a saved and restored world, walking away from them.

Hesitantly, Dust spoke again. "So that's it? I stay here and you leave my world alone?"

Nightmare made a movement like a small huff and said, "I am not in the habit of creating a mess in return for service. As such, this world holds no interest to me." This was apparently as much a farewell as Dust was going to get as Nightmare turned impatiently to the other two and it was clear they were going to leave.

"but boss!" Killer cut in, turning to face rapidly between the lone skeleton with the sunrise at his back, and his master in the ebbing darkness.

Nightmare faced him amusedly. This applies to you too Killer. Even of all the versions most similar to yourself you are not the first to serve me."

His subordinate was astounded. "eheh, boss… are you really telling me that there are ones like me out there living a peaceful pacifist life? heh!… hehe…" The response broke down into nervous, doubtful laughter that died in the face of Nightmare deciding not to comment on this, instead turning with a mysterious smirk, leaving Killer the most confused one there.

The black ooze and negative magic washed up and engulfed his old friends… allies, and without a passing glance back from his old boss the three were gone. Dust stood on his own again. He had truly been left to continue the life he had been lucky enough to have a second chance of.

Epilogue.

Killer caused what chaos he could get away with around Nightmare's castle as he obsessed about what happened for days.

It was absurd. Someone like Dust, with his reason for the constant cycle of killing gone, might be able to move on. Nevermind the surprise that Nightmare would allow such a happy life to take place even among those who served him.

It was apparently possible for Horror too, for his people to make it out of the underground somehow. Though Horror hadn't faced it yet. He had apparently previously tried the portal before giving up again on his world in apparent despair. But what Killer couldn't get over was that someone like himself would have potential to live a peaceful life. Apparently previous versions of Horror, Dust, and others might have moved on in the end and maybe this one would, but still Killer thought; how can I do it?!

Horror might have enough soft spots hidden in his soul to live peacefully, but Killer? Without the Reset ability he once had before coming here? Haha there was no way he would not fuck it up if given a pacifist timeline to live in. The slightest irritation and he would go on a killing spree. Heck, boredom would be enough. He had pretty much no self restraint anymore and just wouldn't care, he thought. Hehehe, just imagining the humans and monsters around him oblivious that any second, here was a harmless looking monster who could flip like a switch and kill them all. The idea of them never knowing was… thrilling…

How the hell would a version of himself do it, was the thought that stabbed at Killer for ages to come.

In another timeline at a customer service desk Sans the skeleton sat at his job quite happily. It was quite a stressful job for some people really. The customers could be complete dicks but Sans dealt with it all with the patience of a saint and an amused tone of voice when the worst of them decided to test him.

In fact he picked this career on purpose. It was a mix of mundanely dull, which seemed to calm the corrupted soul that marked his front, and he actively made a game of being surrounded by plenty of reasons in life why anyone might want to flip. He found this hilarious. In fact he revelled in it. If he decided to one day there was nothing much anyone could do about it, he knew. And he knew that they didn't know about him and his background.

Sans loved this life. In fact he never would flip out during it. He played the upstanding citizen, and loved to keep in mind that of all the people, friends, family and customers of the jobs he gravitated towards; not one of them knew what they were truly dealing with. What mind threw pleasant chit chat like a pro even as it thought other things. As far as they knew him he was the weird, humorous, if slightly dark humoured, stand up guy.

The latest customer came up to the desk, entitled raised voice edging into obnoxious screaming as they thought nothing of venting to the poor innocent service worker.

Sans grinned gleefully and held his hands laced politely together on the desk to ask how he could help them, in the most amused voice, which tended to offset the most irate customers with a confused sense of something not-being-quite-right. Ever unaware, the customer conducted their business with a guy who was quite capable of snapping their neck just for the heck of it.