Sans appears in a darkened room, the only light coming from underneath the door in a thin line that offers close to no illumination. But he knows the small space from one corner to the other by heart, he'd been there for such long sleepless nights trying to figure out what had gone wrong. The blizzard outside can be heard, blowing against what had been his and his brother's house for years.

He leans against the wall for support, his breathing shallow. His magic hasn't replenished fully, and the feeling of loss in his soul was in no way helping that fact. Rubbing his skull with his left hand he flicks a switch, the lights surprisingly coming to life still. He hadn't been there in a long time.

He looks at the counter in front of him. The blueprints were still there, scribbled all over with Gaster's symbols. Sans can't help rolling his eyes, why he chose to use such a complicated dialect was beyond him. Sure, that was his natural font, and it was useful to keep his projects secret, but the small skeleton never liked going through the characters in his mind, taking copious amounts of time to decipher the notes.

He decides to sit down on the floor for a moment, catching his breath. He couldn't do much in the state he was in. Turning his gaze towards the covered up machine he sighs heavily. It's broken. He never figured out how to fix it and even if he had… He couldn't risk turning it on and suffering its creator's fate, he couldn't leave Papyrus all by himself.

With a bit of effort, Sans leans forwards and grabs the end of the sheet that's draped over the invention and tugs. It slides down the machine and onto the floor, leaving it uncovered. The memories it sparks in him are painful and he looks away for minutes that feel like long hours. The mostly metal casing looks as if it's melted in some places and all the screens for the readings have shattered, along with a few lights here and there. The buttons are intact for the most part but the one Gaster pressed to turn off the machine before he got torn apart has a blackened circle around it, as if scorched by the intensity of his magic.

He could still recall the way his skull had started splintering, leaving two large tears that emerged from his eye sockets, one up, one down. Sans shudders at the memory, closing his eyes and leaning his head back. He doesn't exactly know why he came here, but that picture, which he is still holding tightly in his hand, filled him with a sense that he needed to go back to this place. He couldn't explain it if he wanted to.

In the back of his mind there's this notion that your disappearance and Gaster's are somehow related. The only logical conclusion he can reach is that the possible connection is where you both ended up. And this machine, that he could never fix and didn't even know if he actually wanted to, was the only way he consciously knew to get there.

His shoulders slump in quiet defeat as he realises one crushingly obvious fact. There are no more human souls available to him. He has no determination with which to put this thing back online if he does figure out how to fix it. His soul has this constant dull ache, sharp pangs of pain shooting through him every so often, but becoming all the more frequent as time goes by. It's as if somehow his soul knows that yours is struggling, despite not feeling it per se.

The skeleton finally feels some strength return to his bones and lifts himself up off the floor. He opens some drawers digging through them. Most were empty now, he took most of their contents when he and Papyrus moved to the surface. But the blueprints were still there. He had left those behind, thinking that maybe he could finally move on with everyone else. He looks through the sketches, reads all the symbols, just has he had done countless times before. And just like before, it gets him nowhere.

Sans had built this workshop so that he could disappear into his work without bothering Papyrus but still remaining fairly close in case he was needed. He had only brought the essentials in with him. The rest, all of Gaster's research related and unrelated to souls and determination, was all back at his secret lab, back at the core that he himself had built. He grits his teeth and clenches his fists. He hadn't gone there since he got the things in this very room after the accident. He didn't plan on ever going back, he didn't want to.

But right now, what he wants doesn't matter. He needs to figure out how to get to you, and if this is what needs to be done, so be it. He gathers the notes he thinks might be somewhat useful and blips away into Gaster's laboratory.

When Sans reappears with different surroundings something feels wrong. The magic that should've died as soon as he stepped through his shortcut lingers for agonizing seconds that tug at his soul, making him feel like he's being choked from inside out, sucking more energy out of him than he was used to whenever he teleported. And when he feels that tension release, a loud thud sounds through the dark room.

The noise is closely followed by a gasp, a wheeze and a cough, which cause him to turn on his heels to find their source, left eye ablaze with the glow of his magic. In his chest, his souls feels whole again and swells with a short-lived relief. He sees you shaking, sucking in large breaths as if taking them for the first time in your life, coughing from the intensity of finally breathing, finally feeling the air fill your lungs in a wonderful sensation parallel to being born again. Sans would've cheered and celebrated and held you in his arms if it weren't for the moment he looked at your soul.

He can see it dimly glowing, surrounded by a black haze that almost seems to encase it completely and not only that but your magic is also different, seemingly tainted by another. And that's when he notices another soul inside you. He looks up at your eyes they are glowing purple and he stumbles backwards.

Your right hand moves up to your shoulder, where you'd been shot, and a violet aura surrounds it, a metallic sound echoing throughout the room as the bullet clinks to the floor and the hole it left behind closes slowly. That's not your magic, he can tell. It's someone else's.

"You… You're supposed to…" Sans mumbles, stumbling over his words.

"Be dead?" Your voice suggests through pants. It seems raspier than usual, familiarly so. The small skeleton feels lightheaded and like the room is starting to spin. "Now's not the time for that Sans. I can't hold on much longer. She's fighting me out."

Sans shakes his head in a failed attempt to clear his thoughts, trying to make sense of everything. "W-what happened?" He manages to ask.

"She appeared in The Void. My soul survived somehow, I got it back to one piece. She's the one who figured out how to get out. We used the ripple you create in there when you step through it. Quite intelligent this one." Your eyes squeeze shut from what he assumes to be pain. He can't fight the urge to kneel beside your possessed body and stroke your back comfortingly, despite knowing very well that you're not the one who's feeling it. "But The Void isn't a place for a human girl. Complete sensory deprivation coupled with the inability to breathe and the pain of a gunshot wound for what could've felt like days or months… Her mind couldn't handle it."

The explanation is enough to break his spirit. He can't feel happy that Gaster's not dead and that he's actually back here in the physical world knowing that you've broken in the process. Sans can't stop the notion that maybe his nightmare was more of a warning from swimming in his head.

"I'll get her back." He says quietly, more to himself than to Gaster's consciousness, determined to do whatever it takes.

Your body lets out a strangled groan, muscles contracting and causing it to curl forwards, Gaster trying desperately to keep himself tethered to you.

"She… Ugh…" The heaving breaths interrupt Gaster's speech. "She told me she would bring us both back. It's strange but… I didn't want to let her down." Sans chuckles slightly.

"Yeah. She has that effect on people, heh." His voice cracks the tiniest bit. "You said only your soul survived. That means you need a body for it to stay whole here. I can ask Alphys to build one like she did for Mettaton…" Sans reasons in a whisper.

"There- AH curses, she's… There isn't enough time… I don't know how much longer I can hold on. Sans… I'm really glad that you've found a mate. I'm so sorry this had to happen, you didn't deserve it. At least this time I can properly say goodbye." Gaster stops, your face scrunched up in a tortured expression. "Tell Papyrus that despite everything, I cared about you both very much."

"Stop saying such things." Sans says, feeling blue tears starting to form at the corners of his eye sockets and blinking them away. "I'm not losing anyone again. I'm going to take a page from your book. Quite literally."

With his magic he flicks all the switches, the room lighting up in a momentarily blinding flare. The large tube filled with a viscous, translucent liquid catches his eye. That's what Sans needs right now. Leaving Gaster and your body, both struggling visibly to fight one another, he goes to the desk Gaster used, digging through his various papers and coming across the ones he was looking for. Thankfully, the scientist was awfully organised unlike him. He skims through them, slower than he would have if they weren't written in Windings.

ItHe's alive. I made a life. I don't think I've ever felt this much pride and joy.

His soul clenches at those words and he rubs his aching chest through his shirt. He goes back a few neatly numbered pages until he finds the part that will tell him what to do.

I'll need a substantial amount of physical matter to make the body. I've decided to use my right hand as it has enough surface area.

Sans opens and closes his right hand, pain ghosting through it as he pictures how much it'll most likely hurt, how much it hurt the scientist when he did it himself. The other reason Gaster had chosen that one first was because his dominant hand was the left, as was his case. He guesses that will have to do.

"What did you use to cut it?" Sans asks.

"Cut what?" Your voice questions in return, eyes widening as Gaster realises what exactly he meant. "You're not doing that."

"Yes I am. If you won't tell me I'll find it myself."

There's a cough and a gasp from you. "I'll let go right now if you do that." Gaster threatens.

"No you won't. You always had a knack to persevere." A strained smile forms on Sans' face. "Guess I got at least some of that from you, huh?"

Resigned, the scientist uses your hand, which is shaking from the effort of trying to control you when your altered consciousness was struggling so fiercely to take over again, pointing to a small cylindrical device inside a glass case.

Sans walks over to it and takes it from its place, turning it in his hands nervously. It seems simple enough, almost like one of those little punchers that cut little shapes on paper. But with insanely sharp rotating blades that cut through bone instead…

"That's gonna hurt…" He mutters under his breath.

He sets his right hand on a counter, holding the device in his left and injecting his magic into it, making it roar to life with a loud sort of buzz. He lines it over the back of his hand and places it down holding his breath before pushing downward. The scream that comes out of the small skeleton's mouth could chill the blood of anyone who was listening. His left eye glowed fiercely and the cyan droplets that he had held back before fell freely with the unbearable pain that shot through his hand and up his radius, ulna and humerus. His bones rattle as he pulls the device away, blood dripping bright red and fresh from the blades and pooling under his mangled hand.

Shakily, Sans lifts it and pokes the piece of bone through it, crying out once again, cursing over and over, his vision blurred from both tears and mind-numbing agony. He nearly passes out from the wound but somehow holds on. He would've looked at the notes on what to do next but he couldn't see very well at the moment

"W-What…" He tries to ask Gaster for direction but the burn in his hand is so awfully distracting he can hardly focus.

"Put it into the incubator." That's what he called the large tube. "I'll do the rest." Sans nods absentmindedly and did as he was told.

He sees you half crawl towards him, and in his injured state he feels panic take over him, the nightmare from earlier appearing to come to life. The small skeleton manages to calm himself down, finding his reason and telling himself that's just Gaster still straining to stay in control of your body. He drags his feet over to the incubator and pushes the bone inside it, collapsing to his knees beside it, sliding down to a sitting position.

The pinpricks of light in Sans' sockets dart to the side as he sees you next to him. He feels your soul inside you and notices how the physical pain on his hand doesn't even begin to compare to how much his soul is aching for you. The distress emanating from your being, the horror and the despair… He can tell you feel trapped in more ways than one. He can almost see you clawing your way out, and it's evident with how much energy Gaster has to spend to keep you at bay. The thought that you might not be the same as when he last saw you is terrifying. Sans wants it to not be true. Maybe Gaster's wrong. Maybe…

His inner rants get interrupted by the sight of your hand going up to the panel. The glow of Gaster's purple magic leaks out of your fingers and he watches as the bone that was in his hand not moments ago starts reshaping, slowly but surely, into a semblance of a skull. Sans can't help but notice how those cracks from his sockets remained. As Gaster's magic continues to flow into the incubator the body keeps forming, the bones looking perhaps thinner, more brittle than they should, but that was to be expected. It was too little matter to form a fully adult body, despite the minerals and nutrients dissolved into the liquid inside to aid in the transformation. It might've worked perfectly for a little baby bones but this was different.

Once that was done, he looked at you, heaving from exhaustion, sweat beading at your forehead, the lilac in your eyes fading slightly.

"You'll have to place my soul in it. I can't do it myself because I'll lose control of her body once it's out." Gaster instructs through you. Sans nods in response but doesn't move right away, trying to gather the energy inside him.

There's a fleeting thought in the back of his mind. If you really have lost control as Gaster claims… Neither of them will be in a state to protect themselves against you. A bitter chuckle escapes him and your eyes glance over to him, brows furrowed. He forces a grin onto his face and the thought to the depths of his subconscious.

Sans struggles to his feet and puts his good hand on your chest. His eyes drift closed at the tingling feeling he gets from your soul and tries his hardest to focus on the other one. Once he can fell Gaster's soul over yours, he pulls back, the purple heart following right behind. Hearing the thud of your body falling to the floor temporarily unconscious, he quickly takes it and inserts into its respective place. It swims up to the skeleton floating in the tube, settling in its chest and phasing through the ribcage before fading out. The skeleton inside opens its eyes suddenly, glowing the same hue as the soul that just fused with it and Sans presses the button to clear out the liquid, an anxious fear taking hold of his soul as he watches you from his peripheral vision.

You have moved to a different position, curled up on the ground, hands on the back of your head, shaking it from side to side and knees tucked underneath your stomach, trembling ever so slightly, a low, humming growl sounding out of you. Sans tries not to make any sudden movements as he steps away from the incubator and closer to you. Your body twitches and he freezes in place. The glass casing finally lifts up, letting the 'newly born' Gaster step out carefully, bare bones with nothing to cover himself up. Sans can't enjoy having him back yet, or revel in the fact that this actually worked. Not when the atmosphere feels this tense.

Trying to get adjusted to being in a physical body once more, Gaster summons his magic to get himself one of his many lab coats that he kept around. He spent most of his time in this lab anyway, it was only natural. He's cautious, making only small and slow movements at a time in an attempt not to illicit any unwanted reactions from you. Both skeletons are vulnerable right now. At least now he feels less exposed.

With each action calculated and wary, step by tiny step, Sans gets closer to you, until he quietly kneels just a few inches away, his injured hand held up against his chest, still quavering. The low noises that are coming from your body seem almost animalistic. It hurts to watch, but there's still a spark of hope that maybe you're just shaken, and rightfully so. He can't even fathom how tortuous it all felt for you. He reaches for you but stops himself, uncertain. He doesn't know whether he should touch you, no matter how badly he really wants to, or speak or anything at all. Your ribs are rising and falling quickly as your body shakes viciously. He wants so badly to comfort you and to make everything alright, his soul as if screaming in his chest to reach out and touch you.

Gaster wants to tell Sans to step back but he doesn't dare utter a word. The air feels heavy with uneasiness. Your soulmate gives in to his soul's pleas and gently lays a hand on your back.

And in that fraction of a second when he makes contact, everything goes to hell.

Magic erupts out of you and Sans gets thrown across the room, sliding on the floor with a cry of pain as your head snaps in his direction, seeing nothing but him. You get to your feet, bent forwards, ready to pounce, and advance so fast that Gaster just barely grips your arm to hold you back. Without missing a beat your foot comes up to kick him at his side, and he manages to materialise a disembodied hand just in time to block it before it hits him and breaks his bones. But when your eyes flash red and blue, a strawberry aura on your leg sends him flying backwards as well. A purple haze surrounds the rather tall skeleton and he stops advancing towards the wall, inches before crashing into it.

This all happened way too fast for Sans to even attempt to get a hold of himself and you're already on him when he starts trying to get back up. You're crouched over him, straddling his legs, eyes wild, vision a literal red, blurred with a maddening instinct to protect yourself, to not die. But you can't discern friend from foe. Everything and everyone is a threat in your eyes and your only option is to get rid of it. Your right fist is surrounded by your magic as you bring it down on Sans' face, him getting out of its way just in the nick of time, eye sockets widening when the tiled floor underneath your punch cracks to pieces. His left eye flares and he throws you across the room, stopping you before you hit anything, not wanting to hurt you. Unfortunately, the pain that shoots through his arm causes his magic to falter and you're back on your feet in a flash, running towards him yet again.

The sound of a ripple echoes through the lab and Sans' soul feels as if it's getting squeezed when he sees a blaster right behind you, eyes flooding with a violet flame, mouth open and ready to shoot. Instinctively he teleports to you, wrapping his arms around you teleporting you away with him just as the beam blasts past where you were, obliterating whatever was in its way. When you both reappear on another corner of the room, you both crash to the ground, rolling to opposite directions.

"What the hell are you doing?!" Sans shouts at Gaster.

"Trying to stop her!" He rasps back, his voice scratchy and strained from having not been used in forever.

"Don't hurt her! She'll never trust me ag-ARGH!" He gets cut off by you tackling him to the ground, a snarl coming from deep within you as you try to hit him.

Sans puts his feet on your stomach and pushes you off him, using his magic to aid him, your body getting somersaulted over him and against a wall. He gets up to his feet and tries to make his way to you. A choked gasp leaves him and he stops dead in his tracks when he feels his soul getting ripped out without warning, your arm outstretched towards him, eyes glazed over, teeth showing in a feral grimace filled with fear and anger.

Gaster looks on in horror as he tries to do what Sans practically begged of him and not hurt you, not kill you right then and there, protecting his offspring.

You scramble to your knees ready to act. In your head two words echo inside.

Mercy. Fight.

NOTE: Oooooo I had a lot of fun with this one! Like a LOT! I hope you enjoyed it just as much hehe

Thank you so so much for reading, please leave feedback, it motivates me so much and I appreciate every single comment you have :P