The shock happened at supper on a Tuesday; Frisk remembered that clearly because they always thought Tuesday to be the worst day of the week. Monday? They were still riding high off the weekend. Wednesday was at least the middle of the week. Tuesday though? By then the energy they had from the weekend was completely burnt out and they still had the rest of the week to get through.

So, really, it was appropriate time for life to go to shit.

One moment, the four of them were talking over supper—well, five, but Asriel didn't mention if Chara had anything to add to the conversation. It was a particularly nice dinner because Asriel talked Papyrus into letting him help cook the meal—a simple casserole dish, only a little burnt on one side, and even then they ate from that side too. The topic turned to meals they had all had as children. Frisk waxed wistfully over their grandfather's perfect grilled paninis, Asriel even hesitantly mentioned his mother's pies, and then Papyrus snorted.

"Well, at least you have some nice memories of childhood meals," he muttered, putting another forkful into his mouth. "All I got to have was Sans' terrible cooking to live on."

Instead of annoyance or amusement, Frisk was surprised to see pensiveness on Sans' face. He prodded at his casserole with his fork. "Do you remember when he used to give us potato chips and then be surprised when we got hungry again like half an hour later?"

Frisk blinked; the words rang funny in their ears, like Sans had spoken into a long tunnel. But he hadn't done anything in particular to make it sound that way, not even cupping a hand over his mouth.

Papyrus didn't seem to notice. He shook his head. "Yes. The two of you were both hopeless."

Frisk cocked their head to the side—Papyrus' voice also had the same strange quality to it now. It wasn't the first time they'd heard the brothers use the strange tone, but those moments had always been quiet, private moments, so they'd never tried to intrude. Now, however, they were using it right at the dinner table. What better chance to ask than now? "How are you making your voices do that?"

And like that, the room went tense. Now both brothers were staring at them, faces slack as they gawked at Frisk. Papyrus even let his fork slip from his fingers before he managed to find his voice again.

"Frisk," Sans began, setting his fork down, "how are you doing that?"

Frisk frowned. "Doing what?"

"Hey," Asriel piped in, frowning at them. "Don't leave me out! What are you guys talking about and why do you all sound so weird?"

"Weird like how?" Frisk asked as they turned to him.

"Ah! And now it stopped again," he said, sitting back. "How did you do that to your voice?"

"Did what to my voice?"

"That—that thing! That thing that Papyrus and Sans do every now and then," he quipped back; interestingly, Sans and Papyrus both glanced at each other. Had they not realized that Asriel and Frisk had noticed those little conversations?

"I'll be honest, kid, I don't know what you mean—what did my voice sound like?" Frisk asked.

"You did that thing that where they talk in that weird language that I can never make out," Asriel answered, leaning in. "Whenever anyone talks in it, it sounds like they're in a tunnel or something!"

Frisk froze. "Wait, I was doing that? I was speaking in another language?"

"Yeah! I couldn't understand what you were saying—what were you saying?"

"I was asking them how they did that thing with their voice too," they answered before grimacing. "But I understood them just fine. It really sounded like another language?"

For a moment, both skeletons sat, frozen and staring. Then Papyrus's hand started to shake—before they could ask what his problem was, he nearly jumped to his feet and slapped his hands against the tabletop. "But that's impossible!" Papyrus finally shouted, startling Asriel and Frisk. "How on earth did you understand us?"

"Frisk," Sans began, leaning his elbows heavily against the table and scrubbing his face with his hands. "What exactly did you hear us say?"

Frisk glanced at him and tried not let their unease show. "You mentioned something about someone giving you guys potato chips when you were little, I think? You said you used to eat them and then get hungry again afterward. Then Papyrus said that you and that other person were both hopeless."

There was a long pause; Papyrus gawked, jaw hanging open, either in shock or dismay. Sans just quietly cursed and got up, heading towards the cupboards. "I need a drink."

Despite his stupor, Papyrus snapped his arm out and grabbed his brother by his sleeve. "Drink later. We're figuring this out now."

Sans didn't bother to shake off his brother's grip. "There's no point to it," Sans replied, voice echoing again. "They're speaking in Hands, that's all there is to it."

"But how are they speaking in Hands?" Papyrus snapped. "No other monster can speak it—it's our language!"

Frisk blinked. Speaking in Hands? A special language between the brothers—or perhaps between skeleton monsters in general?

"Not just us," Sans said. It seemed enough for Papyrus; his eyes went wide and he let go of Sans' sleeve before finally sitting back down. After a long moment, Sans stalked towards the cupboards and opened the cabinets to dig out a tall bottle of bourbon.

Asriel sighed, aggravated. "Hey, guys, come on. What's going on?"

Frisk watched the two skeletons, trying to control their racing heart. Finally, they turned to the young prince. "Hey, bud," they called; once he looked at them, they gave him a patient smile. "I think that's something we'll have to figure out another time."

Asriel pouted, but Papyrus's shoulders loosened as his body relaxed. He shot Frisk a grateful look. Behind him, Sans paused in his search for alcohol, shut the cupboard, and instead began to search for mustard instead.

Later, when Frisk walked out of the shower, still toweling their hair, they paused in surprise as they looked at the bed. Sans hadn't got out any papers that they needed to go over for later, and instead was sitting at the head of the bed, reclining into the pillows. When they walked out, he was gazing idly out their bedroom window. It was winter in New Home and frost clung to the windows, making delicate patterns on the glass.

Frisk considered him and then tossed their damp towel on the floor, idly promising themselves that they'd pick up later, though they never would. They thought about sitting more towards the foot of the bed so they could properly look him in the face, but decided it seemed a little too confrontational. Instead, they joined him at the head of the bed, sliding in next to him. They waited for a moment then reached out and prodded his hand. When he finally glanced at him, they smiled. "You look like I'm going to stab you."

He snorted. "Are you?"

"Never," they answered with a grin. At his thoughtful look, they prodded his hand again. "You don't really think I'd attack you, do you?"

"This was a world of kill or be killed once," he tried to quip, but even he didn't look convinced by his own bullshit. Tellingly, he offered them his fingers so they could twine their own around his.

They did so gleefully and chuckled as well. "I'd never do it and you know it." To drive the point home, they pulled his hand up and pressed a kiss to his knuckles. "And I'm not going to grill you over what happened either."

He squinted at them. "That's awful considerate of you."

"Being considerate is a talent I've long tried to cultivate," they quipped, setting their conjoined hands back on the blankets. "And also, you two looked pretty spooked when it happened. Like you didn't want to talk about it. Whatever it was, I can wait for a while if you need me to." There were so many other things to worry about—monsters rejoining the surface world, human and monster relations, Asriel's strained relationship with his parents, this odd thing that may or may not be growing between them and Sans—that Frisk knew that this was one thing they wouldn't mind shelving for now.

Instead, Sans paused, staring and then finally closed his eyes. "You know that there's only five other skeletons in the Underground besides me and Paps, right?"

Frisk froze. Huh. I honestly didn't expect him to just go with this. "Yeah?"

"There used to be another one of us," he went on, opening his eyes to gaze down at their shoulder instead of their face. "He had trouble being understood by other monsters besides skeletons."

"I take it he… spoke in Hands?"

Sans looked into their eyes. "Yeah."

Frisk waited for a moment. "Okay."

Sans sighed. "You should know—he's the one who gave you these holes," he said, glancing down at their hands, as if he could see straight through the gloves they'd already pulled on. Frisk froze. "He put that magic in you. He must have also put that ability in you as well."

"Oh." Their voice sounded small, even to them.

Sans grimaced. "And you should also know. He was my and Paps' brother."

They couldn't find their voice for a moment. When they did find out, they could only manage a pitiful "oh."

Oh. Your brother erased a child, stole some data from another person, and created me.

Oh. Your brother kidnapped me and tried to send me into the depths of despair so he could take control of my body and soul to do who knows what.

Oh. You attacked your brother to save me.

"Oh, indeed," he snorted.

They tightened their grip on his hand and let the conversation die for that night.

Three full weeks passed before Frisk broached the subject again. Late one night, after a frustrating evening of trying to find new ways to convince more monsters that humans were no longer their enemies, Frisk prodded the center of their palm and glanced at Sans, who was rubbing his temples. "Was he really your brother?"

"Hmm? What about Pap?"

"Not Papyrus," they murmured. "Gaster."

Sans paused. For a moment, they thought he wouldn't answer, but then he surprised them. "It's complicated. Why do you want to know?"

There were so many reasons they could give him, including the most harmless answer of 'I need something to distract me from this headache', but instead they went with one that was just as honest. "I was thinking about home. My mother and father. Got me curious what your family was like, besides Papyrus."

He quietly tapped his fingers against his knees before answering. "Are you… homesick?"

With a sigh, they slumped over against him and closed their eyes. With them closed, they could almost pretend that they were just lying against Papyrus on the couch, that if they kept them closed that they could hear Toriel, humming in the kitchen while Sans told her jokes to make her smile. They opened their eyes and wondered if they were disappointed or not to still be sitting in bed. "I don't know. Maybe a little."

Carefully, he pulled his arm free from where they'd trapped it against them and draped it across their shoulders. "No," he said, making them look up at him. "Me and Papyrus didn't really have parents. Because Gaster kinda was our parent."

Frisk blinked. "That's, um. It sounds… complicated alright."

Rather than immediately reply, he dug out a pack of cigarettes out of the bedside table and lit one for himself before offering the pack and lighter to Frisk.

They took out a smoke, hoping that it would help their headache, and lit up the stick before handing the lighter back to Sans. When he didn't look like he was going to answer, they decided to try again. "Why do you call him your brother if he was really your father?"

"Honestly?" Sans asked, rhetorically as he breathed out a long puff of smoke. "I think he just hated the idea of us call him that. Heh. To piss him off, I'd call him 'old man'. He hated it." He drummed his fingers against their shoulder before going on. "He didn't feel like our father anyway. 'Brother' felt more right. Usually."

"Can skeletons make children without a partner?" That wasn't how it worked back in their old world—their original's world? Back there, Papyrus had said as much. Sans and Toriel couldn't have had children together even if they wanted to. Something about how skeletons created their children, it wouldn't mesh with Toriel's biology. They didn't know; they hadn't cared to learn back then.

"No. That's why he is technically our father." He held up one of his hands. "You know how he has holes in his hands?"

They could feel the absences in their own palms burn at the thought. "I'm aware."

Their sarcasm made him smile, just a little. "Yeah, well, he wasn't born with those. He cut off a chunk of his hands to get enough biological and magical material and grew me and Pap from them."

They sat up, staring. "He grew you… from some chunks of his own hands?"

Sans chuckled, face looking dark. "He wasn't called a genius for nothing."

They glanced down at their hands, picturing the holes in a new light. The holes in their hands always unsettled them, made their stomach churn and their blood race in their ears. But, the idea that they were symbols of a sacrifice made that brought about Sans and Papyrus—they paused and shuddered. No. The holes in their hands were never that. But, somewhere in the void, there were a pair of hands that had brought two of their favorite people into existence.

Maybe they could learn not to hate those holes at least.

They closed their eyes and curled tighter against him. "Why did he hate the idea of being called your father though?"

"I dunno," he grunted and then paused. "Pap… when he was little, he used to think that maybe Gaster had another family before the war, before the barrier. I know he was already an adult by then, so maybe he did have another family back then. He didn't talk about it much. Maybe it was because that family was his own parents. Maybe he had siblings who he missed. Maybe he had a spouse and other kids and he didn't like being reminded of them.

"But it doesn't really matter. Because in the end, he wanted us to call him brother, so we did."

That was not the last they spoke of him. Despite knowing that it never seemed to make either brother happy, they would always find themselves wondering more and more about Doctor W.D. Gaster until they finally turned to the brothers and asked.

They didn't always get answers, but sometimes they did. The information came in bursts—Sans would say something, Papyrus would recall something, and then some nugget of the past would tumble out of their mouths before they clammed up again.

Sometimes, Sans would find them sitting in the kitchen at three in the morning, going over their papers for work to have something to do, would walk over to the table, sit down, and just start spilling stories from his teeth like if he didn't purge them he'd choke on them like an alcoholic on vomit. Those were grimmer tales, ones that they weren't sure Papyrus would like to hear spoken, thus they were saved for those lonely times when it was only Frisk awake.

This was what they did learn.

Gaster was a Royal Scientist before the War and the imprisonment of monster kind. Back then, the title had been Royal Alchemist, but that changed later on, something monsters had picked up from humanity. He'd been the one to insist on changing the title—he'd never dabbled much into alchemy in the first place, but then he hadn't much cared for being called a "natural philosopher" either.

Monster kind had once spread far and wide, little different from humans, and those monsters with communities closest to humans were first attacked, which included skeletons. They, the entire skeleton race, were erased except for six beings.

Gaster hadn't even been home, which was why he'd been spared. He also hadn't been there for his family's last moments.

After being sealed into the depths of Mount Ebott, the skeletal survivors separated, disappearing into the shadows and silence of the caverns rather than be forced to live in the cramped spaces that monster kind was settling into. Only he hadn't vanished; perhaps too tied to his work, perhaps too hesitant to cut ties with the monarchs who were in dire need of his help. Perhaps he'd volunteered to stay in the limelight, to be available to the others whenever they had need for him.

The brothers didn't know.

Gaster created many new wonders to aid monster kind, made many discoveries—from harnessing geothermal energy and creating the engineering wonder of the CORE, to discovering the effect of lack of empathy had to a monster's magic, to the reason why monsters fell down, to mapping out the components of a human soul. He'd fostered new generations of scientists, written books about every branch of science that interested him.

He'd done so much. And yet, he hadn't been able to cure Chara when they fell ill from buttercup poisoning, nor saved Asriel before he died.

He couldn't stop the King from creating a terrible law. He couldn't stop the Queen from leaving.

He couldn't help any of it.

For over fifty years, he'd been as helpless as the rest of monsters as their world went to hell.

And then he decided to do something for at least one of those problems.

For decades more, he studied.

And then he cut a whole out of the palm of his hand. Then he grew a skeleton out of it.

Sans. The first new skeleton birth in nearly two millennia, as far as Sans and Papyrus knew.

Sans remembered the first time he really looked at Gaster and recognized him. In the incubation tubes, everything was blue and bubbly. If he kicked and flailed enough, he could create a storm of bubbles which had been his only source of entertainment aside from the blurs. Outside the tubes, there was nothing but shadows. But sometimes, something approached the tube, a long pale figure would stand near the tube for a few moments before disappearing back into the shadows.

There was little to really see of the figure, which is why Sans hadn't realized it was another living being until the figure pressed his hand up against the glass.

The figure had never touched the glass before—or at least Sans didn't remember if he had. But now a hand—massive in comparison to his—pressed against the glass, palm flat, fingers spread. Sans had reached for this new thing, pressed his own tiny hand against the thing, and stared. His small hand was completely dwarfed, his whole hand fitting so easily just inside the hole at the center of his metacarpus that he could have pressed his other hand and his feet and still have extra room. He stared, noticing that despite the differences in size and that while his metacarpal bones weren't fused or even the giant hole in the palm, the hand was still very much like his own. And that could only mean that on the other side of the glass, something just as alive as him was waiting, watching. With a burbling cry, he smacked his hands against the glass and flailed. He wanted to be out there too, to know who was there, and to not be alone.

Gaster pulled him out of the tube the next day.

Before then, Gaster had been looking in through the glass at him and saying 'my latest experiment'. After Sans had reached back and then threw a tantrum at the injustice of being alone, he said 'this child, my brother'.

"Probably just didn't want to deal with the pressure of being a father," Sans said abruptly at four in the morning during one of those long nights that sleep eluded them both. "But fuck, who knows why the old man did it."

"Maybe he just wasn't ready to be a father," Frisk offered, voice soft. "Or perhaps wasn't ready to be one again, if he did have children before."

Sans shrugged. "Like I said. Who knows."

Sans was not an easy child—his overall health was never fantastic, but in the confines of the secluded laboratories that were kept restricted, he grew quick and curious. He was constantly getting into something, demanding attention and then answers. Despite not wanting to be much of a father, Gaster never stopped answering his questions or helping Sans seek out the answers for himself. He wasn't much for affection or comfort, but he taught Sans to read before he was three and encouraged him to press farther. When it came to knowledge, Sans was free to explore and study as much as he wanted. But only as long as he stayed in the labs.

Outside the labs, monsters killed each other constantly and the population dwindled. Inside, Sans was safe. But he was also very alone, with only Gaster for company.

He was five when he looked into the dictionary, skimming the entries until he finally found the definition he was looking for. Having found it, he read it, focused in on every dip and curl of every letter until he snapped the book shut and dragged it to Gaster.

Gaster only raised an eyebrow ridge as Sans hefted the book up into his caretaker's lap, opened it to a page, and pointed. "I want this."

"You already have books. Do you want a new one?"

"No, this," he insisted, tapping the page. "I want this."

Gaster read it and frowned. "You want a sibling? Sans, you already have a sibling."

Sans put his hands on his hips. "I want a younger one. You're too old."

Gaster blinked down at him for a moment. "Really, child. You know how to cut a person."

Sans beamed up at him. "Down to the bone!"

The older skeleton snorted—where had this child gotten that sense of humor from anyway? That was the constant refrain Sans heard him asking himself—but turned his attention back to the book. He considered it silently for a long time. Even after he sent Sans to bed, Sans crept out of his cot to watch Gaster ponder the book, his left hand's fingers pinching his fused together palm.

It'd be weeks before Sans would wake up one morning to find that Gaster's good hand now had a matching hole in it and a lump of bone and magic floated in an incubation tube. He had no idea how his brother mutilated his own hand, healed it, began to create a whole new life, and then treated the whole thing as if it was less interesting than looking at another report.

"That's how he was," Sans shrugged, fidgeting with a bottle of mustard, tucked into the curve of Frisk's body as they sat, smashed together on the wicker bench of their balcony. Below, they could hear Asriel and Papyrus—the child had begged for some help learning how to ride a bicycle. Unfortunately for him, Papyrus didn't actually know how to ride a bike, so mostly the lessons consisted of tilting over until he could flop safely on the grass.

Frisk should have gone down there to actually teach him, but at the moment they were focused on their arms around Sans, one hand buried in the folds of his coat while with their other hand they dug their thumb into the empty space of their palm and wondered. "So he was distant. A lot?"

Sans snorted. "All the goddamn time. Aloof summed him up pretty well. He liked being alone with this thoughts and he seemed to think that everyone else should be just as satisfied too." He paused and shot a squirt of mustard down his gullet. "He just wasn't big about really caring what others thought. All he would think about when it came to that was how to make sure no one got murdered."

"And how did that usually work out?"

"Well," he began before shrugging. "Pap and I made it to adulthood, didn't we?"

"After some near misses." They tapped his skull, curious. "You said he used to keep you and Papyrus just in the labs, right?"

"Yeah. My defense has always been really shitty, and Papyrus was too young. His stats were better, but he was a sweet kid."

"Didn't have a mean bone in his body?"

Sans chuckled. "Yeah. Something to that effect."

"So," they began, idly tracing loops and circles against his shoulder, "why did he decide to let you guys out?"

Sans looked away.

It had not been Gaster's choice to introduce the boys to the outside world. Before then, they'd been more or less content with their small world; they knew they weren't supposed to leave, but that hadn't been quite so troublesome. They'd been curious about what was outside the private labs, about the other scientists Gaster mentioned on occasion, but neither were really busting down the doors trying to get out either.

After Papyrus grew enough to survive outside the incubation tube as an infant, Sans had always been very taken with him. He wanted to do everything with his baby brother and never wanted to hand him over to Gaster for anything. He would only reluctantly hand him over when Papyrus would get into incessant crying fits. Even then, he'd only wanted to look after his brother and hated admitting defeat when he couldn't find away to quiet him.

When Papyrus grew, Sans stayed by his little brother's side nearly around the clock. He taught him everything he could—he got Papyrus walking and talking early, taught him how to read by four, and had him learning how to use magic before then.

By five, he'd been quite the little prodigy when it came to magic, even learning how to summon Gaster Blasters. Not even Gaster could claim to be as proud of Papyrus as Sans. With his magic increasing, they were allowed to visit more of the labs and even the CORE.

The CORE was where everything changed. The boys were still young, Papyrus having just turned five, and both were excited at first to see the CORE. Their excitement faded when they realized they'd only been brought to the CORE so Gaster could do some diagnostics on the machines. He let them wander about the catwalks as he worked; the machines were delicate things and he had to climb up into awkward places to check everything. While the boys reluctantly stayed back and played, he had to clamber up and down the walls, checking the machines behind the panels.

It was bad luck the power surge happened while Gaster had his hands buried into some of the guts of one wall. The CORE's magic surged, flaring a bright white that dazzled the boys; Gaster never saw it as magic transformed into pure electricity and shot through the CORE's innards. Most of the fail-safes kicked on in time, saving the delicate wires and coils from shorting out. Unfortunately, Gaster had shut off the ones for the circuit he'd been working on. Power grabbed him, locking up his arms as white hot energy shot up his arms.

The blast knocked him loose from the wall and he swam out of unconsciousness as he started falling towards the wells of magical light under the CORE.

Only Papyrus saw their brother start to fall as he turned to ask a question. With a shriek, he reached out and gestured to Gaster, fingers curling in as if to pull him back. Surprisingly, it worked—blue magic enveloped Gaster's body and yanked him backward. While he didn't keep a hold of Gaster's body for long, the magical pull was enough to send him crashing safely back onto the catwalk.

Sans saw all this from the corner of his eye socket. When Gaster smacked into the iron grated floor, he ran over and checked on him. He helped Gaster sit up, still dazed. It took him a few tries, but he finally managed to explain that he was fine before he asked what exactly had happened. Sans told him quickly and they both turned to look at Papyrus.

Papyrus, for his part, was so nervous he just immediately began to cry. Once they managed to reassure him he wasn't in trouble, Sans having to pointedly glare at Gaster to get him to back him up, Gaster hurried them back to the safety of the labs.

He looked thoughtful as he put Papyrus to bed that night. When Sans asked him why, he still looked like he was thinking it over. "Well. I suppose if Papyrus has a good enough handle on blue magic, I really don't have a reason not to take you two to meet the Overlord."

"Why would you want to take us to meet your boss?" he asked bluntly.

When Gaster looked down at him, there might have been a trace of pride as he squared his shoulders. "This proves that I have successfully created entirely new lives who are nearly identical to children created by more traditional breeding. While your stats might not be terribly impressive-"

"Thanks, old man. Really appreciate the vote of confidence."

"Oh shush, your intellect makes up for any inadequacies you might have on the battlefield." The backhanded compliment was enough to startle a chuckle out of Sans; judging from Gaster's little smile, that'd been his intention. "But Papyrus' stats are exceptional for a child of his growth. He proves that we can use my methods to start breeding more monsters, especially ones from the endangered lines."

"Ah, well. He'll get a kick out of being monster kind's beacon of hope."

"That better not be jealousy prompting that," he grunted, turning to flip through a folder of papers. "I won't stand for squabbling out of you two."

"It's not jealousy," Sans groused back, climbing up onto a stool. "I know I'm just a prototype. He's the perfected model."

Gaster didn't even bother to dignify that statement by looking up. "Prototypes are important parts to creating any new project. Besides," he set the folder down began typing away on his computer. "Papyrus wouldn't see you as a prototype."

Sans fell silent before finally chuckling. "Yeah. Probably not."

"How old were you when you guys met Asgore?" Frisk asked one afternoon. They and Papyrus were in the garage, Frisk teaching him how to change the oil in his car. Out of the back of the garage, they could hear Asriel playing in the sprinkler, trying to ignore the summer heat. He'd been annoyed because they'd all been banned from the public pool—Asriel shed too much, Papyrus threatened other swimmers too much, Sans kept scaring kids by napping in the shallow end, and Frisk had a panic attack when some rambunctious kids knocked them into the deep end, leading to Papyrus threatening everyone in the first place.

Papyrus frowned—they weren't sure if it was because he was focusing on watching them prep the new oil filter, or if it was because he didn't want to answer the question. Finally, he grumbled as they handed him the filter so he could put into place himself. "I was five. Didn't Sans tell you anything about this already?"

"Most of what I get out of him is just bits and pieces. He started telling me once, but then he trailed off and I never got to hear the end of it. Do you not remember much of it?"

"Well, that was fifteen years ago."

"Yes, yes, you're quite the old man now."

Papyrus looked very satisfied as they both took a step back from the engine. "Twenty is a very respectable age for a monster."

"Yep, you're a full grown adult. So old and grown, you can't even remember back to your childhood," they added as they turned to clean up some of the mess they made, turning before he could catch the look on their face.

"Rude," he growled, but there was no bite to his words. After all, he'd been the one trying to dodge the question in the first place. He sighed and looked away. "I don't honestly remember all that much about meeting the Over—Asgore."

"Well, what do you remember?"

Papyrus considered the question before finally answering. "I remember being more excited by the fact that we had all left the lab together and actually gone into the city. New Home was a bit overwhelming and our brother was very careful to keep us close as we walked through it. Monsters usually wouldn't have attacked a family out together, but he was cautious with us being out. We weren't out for long—we just transferred from one elevator to another and then we went straight into the castle.

"The castle was… intimidating for a five year old. Even as someone who was always very great, I stuck close to my brothers while we walked the halls."

"Well, it was a very sensible thing to do," they offered.

He nodded, smirking. "Yes, exactly! Anyway, we walked for a while after that. We didn't go to the throne room. I remember being disappointed we didn't get to see it. Instead, it was probably one of the smaller meeting rooms elsewhere. Easier to defend, I think.

"I can't say I actually recall seeing Asgore's face. I know I must have looked at him, but I," he paused, frowned, and then cleared his throat. "But then I was struck by a very humble and gracious moment, so I wisely put my head down to not astound everyone with my young, but undeniable greatness."

Meaning he got shy and probably hid behind Sans. Frisk had to bite their lip not to grin. "I see. Even back then, you were a very wise child."

"Of course! Would you expect anything less from someone as amazing as I?"

They went to rest their chin in their palm, remembered the oil on it, then switched to resting their chin against the back of their knuckles instead. "Oh yes, very much so. I would have been incredibly intimidated if I'd been that little and met Asgore. I really couldn't compare to you at all."

Papyrus paused and looked a little sheepish. "Well," he began before patting their shoulder kindly, "perhaps I was a tad intimidated, being five and all, but I'm sure you would have been very amiable and polite."

Frisk grinned. At five, they probably would have pissed themselves and cried to their grandfather. It wouldn't exactly be a great meeting. "You're all kindness, Papyrus. Thank you."

He huffed, pleased, his skull a little pink from all the praise. "Yes, well. Where was I? Ah, the Overlord—Asgore. Anyway, he listened to our brother talk for a while, no doubt explaining who we were and how we came to be. Then he talked to me and Sans directly. Well, mostly Sans."

"Courteously allowing him more time to talk since he was older, huh?"

"What else? He was quite pleased with our brother for his work with us. He even immediately agreed to dedicate more funds to start more projects to revive the endangered bloodlines." He frowned. "But, in spite of that happy news, I remember him being… displeased."

"Oh? What about?"

"The fact that our brother had kept us confined to the labs. It would keep us coddled and unprepared for the world outside once we grew up, he said. Which was correct," he added with a shrug.

Frisk didn't doubt it, but knowing Asgore, they wondered if perhaps there wasn't a bit of parental concern that maybe the boys would become emotionally or mentally stunted from being stuck in the same place for so long.

"Our brother agreed after some lengthy persuasion." His face sobered as he finished. "I'm sure it was well meant, but considering… what happened a few weeks later, with. Well. You know."

Doggo. Yeah. They knew.

"Perhaps it would have been better if we'd stayed in the lab," Papyrus admitted softly, looking at but not truly seeing the car's engine.

"Perhaps," Frisk agreed before reaching out and giving the hand closest to them a squeeze. When he looked at them, they smiled. "It's not really for us to know what could have or would have been."

Papyrus looked at them before finally squeezing their hand in return. "Most likely."

"What happened after that?"

They meant for him to talk about the weeks or months later, but he surprised them when he opened his mouth. "After the attack, Sans hurried me home. I was… out of sorts. He-" he clenched his jaw. "He wouldn't answer me at all! I was frustrated to the point of tears."

Frustrated and terrified to tears maybe, they thought, but they'd never say that aloud. "So, he didn't talk to you at all the whole way home? What about once you got there?"

The frustration slid off Papyrus's frame, but he looked no more pleased than before. "He left me with our brother. Gave the barest explanation, so I had to answer the rest of the questions. Which was… admittedly," he grimaced, "not something I was really… prepared to do."

They rested their head against his arm, hoping the closeness would help. Maybe it did, maybe it didn't. "But you did it?"

"Obviously. Would you expect anything else?"

"Always the consummate professional." They smiled faintly before letting it fade. "What happened then?"

Papyrus tugged on his gloves, as if they'd suddenly slipped down—extremely unlikely. Something about skeleton auras actually kept their clothes in place as if they were cemented, if they weren't running helter skelter everywhere. And yet, he still didn't answer.

How to explain? It was, after all, a private memory of a painful time. But, this was Frisk. Frisk was important to them all; they could be trusted with sensitive information like this. After a moment, he found himself speaking as he dived back into the memory of being small and scared and frightfully alive while out in the Underground another was not because of him.

Papyrus had wept into his hands, pressing them against his eye sockets. His mittens, coated in a faint layer of dust, laid on the floor next to his coat. Gaster had dropped them there after he winced at the grey smudged cheekbones of the child that now half slumped against his knees. The clothes would be burned later since monster dust didn't come off anything unless you fought hard against it. Even the hand towel that Gaster used to try and scrub the dust off his youngest brother's face would be destroyed.

Papyrus choked on a hiccup that was half a word, half a cough, but was enough to finish an explanation of what happened. Papyrus's ribcage hitched painfully as he tucked himself against his oldest brother's front. "I'm s-so-sor-ry! I—I m-messed up e-everything and—and Sans hates me!"

Gaster, seeing the child's face was mostly clean, dropped the hand towel to the floor. "Sans does not hate you."

"He does!" Papyrus insisted, sounding as though the words were going to make his soul break through sorrow alone. "He h-ha-hates me! I've r-r-ruined ev-everything!"

"Sans does not hate you," Gaster said again, voice firm. "And I won't repeat myself again."

Papyrus sniffled and blinked up at him, leaning heavily into his brother's knees. "But…"

"No. I won't have. Now, then, Papyrus, you listen here because I don't want to be repeating this on for the rest of the night either. What happened was not your fault and you, frankly, didn't do anything I wouldn't have done if I had been in your place."

Papyrus stared, so surprised he forgot his tears for a moment. "What?"

Gaster frowned down at him for a moment before he reached down, slid his hands under his brother's arms, and hoisted him up in the air. After his little brother let out the tiniest gasp of surprise, Gaster settled him on his lap so he could stare him more directly in the eye sockets. "You protected Sans, Papyrus. You did just as a brother would do. What I would do. What Sans would and will probably do in the future to, as will you and as will I. There is nothing to be ashamed of. With you hadn't done what you did, we might not have Sans here at and isn't that far worse than what did happen? Hmm?"

"Uh, yeah?" he offered, startled.

"So then. If Sans being alive is good, then you have done nothing wrong. So, he has no reason to hate you—not that he does—nor do you have a reason to cry. You did good work and were a good brother, Papyrus. That is what matters."

Papyrus paused for a moment before tossing his arms around his brother's neck. "Okay," he murmured, trying not t sniff again. "Okay. I… I did good."

Gaster froze, hands faltering for a moment before coming to land stiffly on Papyrus's back—he never seemed sure what to do with hugs—before managing a few awkward pats. "Yes. Yes, you did." Carefully, he reached up and untangled the smaller skeleton's arms from his neck. "And now that I know I can trust you to look after him, I'm going to need you to promise that you'll keep looking after him."

"Me? Look after him?"

"Yes. I believe you can do that. Will you?"

Papyrus paused to scrub at his face; once he was satisfied, he looked up and nodded. "Mm! I swear, I'll do my absolute best, so you can count on me!"

"Good. I expect nothing less from you."

But while it's easy to keep a promise if you follow the words, it's harder to keep it by the spirit. He did do everything he could to keep his brother safe from harm. And yet, a warmth in their relationship had gone out and Papyrus was afraid to put his finger on the exact cause. Maybe if it hadn't been their two personalities together, maybe time would have soothed out some of the rough edges. Instead, space seeped into their relationship.

In the future, Sans would admit that it was him that pulled away first. Guilt ate at him and he pulled back from Papyrus. When that happened, Papyrus went to Gaster—who'd never quite known how to handle the neediness of children, but tried to be patient. Finding himself alone, Sans tried to say something about it to Papyrus once. He'd only meant to be a little teasing—"running off to sob at that old sack of bones, huh?" But truth turned the words bitter in his mouth and when he said it, there was a sharpness that cut to them. "Aren't you too old for that?"

The brothers talked less and less after that.

Alphys, surprisingly enough, revealed that she had some strange almost recollections of Gaster. She admitted it after Undyne announced she wanted to try and have a child, after Alphys nearly had a panic attack just trying to think over the logistics of the pregnancy. She ended up huddled against Frisk's side, hands held by Frisk's to keep her from digging at her arms.

Giving the thick fingers a squeeze, Frisk called her name. For a moment, that haunted look in the scientist's eyes disappeared and Frisk was almost triumphant. It returned fast, but it felt encouraging. "When did you first meet Sans?"

Alphys had to consider the words, which meant she was distracted. Good. "I was an intern. He was also an intern, but he was younger than me. F-fifteen! I was annoyed to see that the Royal Scientist would pick his…" she paused, frowning. "Uh. His…"

Surprise clamped down on Frisk's heart as hope bloomed for a far more selfish reason. "His brother?"

"Yes!" Alphys paused, frowning. "He must have been. I was annoyed at first but then I saw how smart Sans used to be. Back when he put effort into stuff, I m-mean."

Part of them wanted to bristle and come to Sans' defense, but they sat that aside. "Alphys, you knew Gaster?"

"Gaster…" she stared at the floor. "Huh. That's right. That w-was his name. He must have been a skeleton too."

Frisk's lips twisted as they grimaced. Okay, maybe she didn't quite remember him. At least it seemed to be distracting her from her panic attack from earlier "You don't remember if he was a skeleton or not?"

"No. I mean, y-yes, he had to be. He was San's brother after all. That's how Sans got the job in the first place." She sighed. "Fifteen years old and already an assistant to the Royal Scientist. He always was a lucky b-bastard. I would have chewed off my own hand for an opportunity like that."

Frisk blinked. Fifteen years old? I mean, yeah, I knew he was a scientist for a while, but that's a little much, isn't it? "Just what was it you guys were working on back then?"

She snorted and shifted around. "What else would we be working on? How to get around the Barrier. In the end, everything always led back to getting past the Barrier. No one wanted to wait for more souls to fall, so we all tried to find ways to escape. There were thousands of experiments we did, trying to get base readouts from the Barrier, trying all kinds of magic on it to see what could affect it the most. There were some projects that were there to help better our lives, but those were never as important as destroying the Barrier."

"And what was your project?" they asked, smiling at little to see her looking calmer yet. Or at least more distracted from her worries. Either worked. "Something to do with robots, maybe?"

"I was trying to recreate humans s-souls. I wrote a thesis paper when I entered the university's science program. Someone found it and recommended me as an intern for the Royal Science Division." She sighed. "It never worked—we could break down some of the mechanics of the soul, we could figure out how to extract determination out of it, but we could never create a new copy of a soul."

"Well, what else did you work on? They can't all have been failures."

Alphys rolled her eyes. "Of course, they were all failures. We never got past the Barrier."

Well, sassy was better than nothing, Frisk supposed. "You know what I mean. Wasn't there any memorable experiments you guys had back then that lead to some good?"

Alphys stewed for a moment before answering. "There was s-some stuff. There was Sans and Papyrus if nothing. Recreating monster family lines was put on the backburner for a long time though. It wasn't easy to find monsters willing to give up chunks of their bodies just to make children they weren't sure they could raise and take care of. Then there were all the weaponry we ended up creating when we hoped we could just crack the Barrier open with brute force. That's where Sans and Papyrus ended up getting some of the stupid shit they use to attack."

Ah, yes. The Gaster Blasters—Papyrus had been the one to explain those to them while Frisk tried not to look uneasy when he showed them off. They could still remember trying to dodge Sans' during their fight.

"And there was Sans' project too," she continued, sounding distant. "That one… it showed lots of promise. That was… it was based off some of the doctor's old blue prints. I remember Sans, when he first proposed the project to the head scientist, he was excited. We all were. We thought we'd finally found a way to bypass the Barrier."

"And what was the project?"

Alphys blinked, looking at them as if realizing they were there for the first time. "What?"

"The project, what was it?" At her continued blank stare, Frisk frowned. "The one based on Gaster's blue prints?"

Alphys just stared. "Who?"

Before they could ask again, there was a sharp knock at the door. Sans stepped in, raising an eyebrow ridge at them as they were still sitting huddled together on the floor. "Hey, Undyne's looking for you. She sent me to come find you."

"What? W-where is she?" Alphys asked, scrambling to get up.

"Back in your kitchen last I saw. Hurry up, I don't want to have to hear screaming anymore as she looks for you." He stepped aside to let her hurry past him, but once she vanished, he turned back to Frisk. He walked over to them and helped them up, neither speaking for a moment. Both already knew what he was going to say anyway. Still, he supposed he had to try anyway. "Don't bother asking Al anything about the old man. You'll just get a headache trying to chase down clues she doesn't have."

"What happened? She just forgot all of a sudden," they said before pausing. "Or at least I thought it was all of a sudden. It was… weird."

He shrugged. "It's what happens to anyone who starts to remember him. They'll know what you're talking about for a minute or two, but the memories are gone again in another minute. There's no point bothering to ask about it."

Frisk frowned. "But I don't forget."

"Yeah, I noticed," he quipped, mirthless before idly scratching his jaw.

They tried not to clench their jaw when they saw his nervous tick. "You probably have a theory too then, huh?" When they didn't get more of a reaction than him shifting around, they smiled, but it never reached their eyes as they patted his shoulder. "Actually, don't tell me if you do. There's some things better left unsaid, I think."

"Papyrus, why did you become a sentry in Snowdin?"

Frisk paused and looked up from their paperwork to see Asriel and Papyrus sitting on the couch, the two of them distracted from the television while an obnoxious ad played on the screen. They couldn't blame either for ignoring it.

Papyrus answered promptly. "Because I wanted to become a member of the Royal Guard of course! I was too young to join the Guard proper, but the restrictions are lower for sentries. So, I figured it was my best shot to be a Guard sooner, if I could impress Undyne with my diligence and spotless work record."

"And you must have," Frisk said, smiling. "You are a perfect Guard of course."

"Yeah," Asriel laughed. "You're the best at it!"

Papyrus tried to look humble as he preened, smirking broadly. "Yes, of course! I surely had no doubts about it. Although," he reached out and patted the top of Asriel's head. "I do have to acknowledge that I have a pair of very exemplary charges to look after." While Asriel laughed in delight and some embarrassment, Papyrus glared at Frisk, although they could see the teasing glint in his eye sockets. "You could learn a thing or two from our princes, Frisk. You're never too old to learn some new things."

Frisk barked a laugh before they could even pretend to be offended. "Ouch! Oh, Papyrus, you wound me. How could you cut me like this?" They looked at Asriel. "You hear this? If I die of a broken heart tomorrow, you'll know why."

Rolling his eyes at their dramatics, he turned back to Papyrus, face curious. "Papyrus, how old were you when you became a sentry anyway?"

"Fifteen."

There was a moment of silence as Asriel gawked and Frisk's pen slipped from their fingers. "Papyrus," Frisk began after a beat, "did you just say you were fifteen when you become a sentry?"

He shot them a flat, unimpressed look. "Yes, human, I did. Try to keep up, please."

Ignoring the barb, they went on. "And you said that when you became a sentry, you moved to Snowdin."

He paused, finally realizing what the problem was. "Yes. There was no need for more sentries in any of the other parts of the Underground, so I had to go to Snowdin." He smirked. "I was taking care of myself for a long time. Are you impressed?"

Frisk snorted, shaking their head as they snatched their pen back up. "More like astounded. You moved across the Underground, at the height of the Edict, to a place that you had known enemies. For a job. When you're fifteen!" They looked at Asriel. "I feel so unaccomplished now."

Asriel gazed at Papyrus, starry eyed. "You really are the coolest."

Papyrus's skull turned a funny shade of red while he wore a doofy smile and a shy look in his eyes before he turned to look at the tv. "Oh, look, our show is coming back on! Shall I turn it up? Eheheh?" Despite the fact he was still squirming from pleasure, he reached out and grabbed the remote.

"Forget the show, I want to hear more about when you came to live in Snowdin!" Asriel shouted, tossing his arms up into the air in wild excitement.

Grinning, Frisk sat their papers aside. "Yeah, come on. I bet you got some great stories about it."

"There's really not much there to tell. Just know that I was as great then as I am now and that's all that really matters."

"Oh, come on!" Asriel shouted before trying to grab the remote when Papyrus started to turn the volume up. Even though he couldn't get it from the skeleton, he was still grinning as he failed. "I want to hear about it. Did you really live all alone? How long were you by yourself? Can you live by yourself when you're just fifteen? Weren't you scared to be there alone?"

"Weren't you scared to be there alone when you knew there were people who wanted you dead?" Frisk asked bluntly.

The two of them kept pestering him with questions; eventually, he gave into the onslaught and turned the volume back down to answer them. He was at equal measures boastful and humble, honest and prone to exaggerate. Frisk and Asriel, and Chara who would get Asriel to ask their questions, eagerly played their roles as the audience until he was spinning them stories of his brave exploits.

"But, Papyrus, dear," they teased while Asriel was still giggling in delight over a story about the time Papyrus tricked Gyftrot into getting his antlers stuck in a tree after he tried to fight the sentry when he came to yell at him for terrorizing the locals. He had to untangle the other monster after that, leaving him to sheepishly grumble and wander off. Knowing Gyftrot as well as they did—he was one of the few monsters who pointedly refused to leave the Underground, so they had to check in with him often—they could just imagine his hangdog manner as he walked off, and they had to agree it'd make for a silly sight. "You still haven't answered all of our questions."

"What question?" he shot back, as he reclined deeper into the couch cushions.

"When you first moved to Snowdin," they reminded him, smiling softly as they put their chin in their hand, "were you scared to be alone there?"

He considered them before shrugging. "It's not as if I'd never been alone before, you know. But you overestimate the danger. I was still young enough that most people would have left me alone, even if I wasn't still wearing stripes. And despite our very obvious… dislike of each other, the Canine Unit mostly left me alone back then." He frowned thoughtfully. "I was too young to target, and not the real source of their ire. They viewed Sans as the source of the trouble, not me." He shrugged. "And it wasn't as though I wasn't without outside protection."

"Outside protection?" Asriel echoed. To Frisk surprise, they felt their own shoulders relax—without thinking about it, they'd gotten a little tense over the thought of a young Papyrus alone in the world, even if it was in the past.

"Mm. People looked in on me a few times a week. Undyne herself came and visited me the day after I moved in." He smirked. "It would look bad for them to attack a personal protégé to the Captain of the Guard after all."

Frisk was fairly certain that most monsters in the Enforcers wouldn't really have given a shit about that, but they had no urge to tell him that. They had heard enough from Alphys about having to fix up Undyne after one of her underlings attacked her to know that while Loyalty was a trait prized by monsters, the Enforcers weren't big on it.

"And from the town itself, I did have Grillby," he added, looking uninterested.

Frisk blinked and sat up. "Grillby? You were friends with Grillby?"

"Mm," Papyrus hummed, tugging at his gloves, making Frisk pause at the nervous tic. "Not me. He and my brother went back a long time. He asked him to check in on me a few times a week. We didn't talk much. It's not like I'd go into his bar if I could help it." He looked away. "Anyway, even if the Canine Unit wasn't afraid of annoying Undyne, those idiots wouldn't try testing the anger of the owner of their favorite dive." He snorted. "Riffraff."

Asriel stared. "Your brother? Sans was friends with Grillby back then?"

When Papyrus hesitated to answer, when he wouldn't lift his eyes to eve look at the prince, Frisk knew.

It was not Sans who was friends with Grillby back then.

Clearing their throat, they looked pointed at the clock on the wall. "Asriel, aren't your cartoons coming on soon?"

The prince perked up and Papyrus was happy to change the channel—and the subject—without a fuss.

Later, after Frisk tucked Asriel into bed and sat with him for a while, chatting, they left the sleepy prince to sleep. When they turned, they saw Papyrus standing in the hall, looking tense and thoughtful. Blinking slowly, they turned and walked down to him. "Papyrus?" they called softly, trying not to wake Asriel.

Papyrus glared at the floor for some time before finally glancing up at them. When he did, he sighed and looked away. "It wasn't Sans who asked Grillby to check in on me. I know you figured that out."

"I did," they admitted, walking over to him. "Did it bother you? Him helping you so much back then?"

He stared at them. "No, of course not. We're… we were… brothers, after all." He paused, looking back down. "Well. Better at being brothers to each other, maybe."

They put a hand on his arm. "I'm sure you were good at it with both of your brothers." When his shoulders finally relaxed a little, they smiled and decided to change the subject. "So, what was it like? Moving to Snowdin. Did you get set up with a house, or did you have to go house hunting?"

Papyrus considered them before answering. "Actually, we went house hunting. Our brother wouldn't agree to let me live in Snowdin on my own before he could see what kind of defenses I could put into a house there."

"Sounds interesting! Why don't you tell me more about it? Come on, we can sit on the couch. Don't want to wake Asriel up talking?"

With a nod, Papyrus let them lead him down to the living room.

A/N: Oh, god, I'm sorry this is so late. This chapter has literally been in the works for MONTHS, since nearly the beginning of me starting MaKW, and I barely got this much out of me in time. So, this is part one of the backstory for all three Bone Bros; it's choppy and messy and abrupt, but if I don't post this now, I'm not sure if I ever will.

So, that aside, today is officially the one year anniversary of me posting the first chapter of The World, Upside Down. Lately, I've been working with a beta reader to clean up some of the more unsightly errors, so I'm going to try posting the corrected chapter one today. If you ever want to re-read it, now might be a good time. (Although now right now, I still got to do one quick read through before posting it.)