Notes: Story is a [prequel], this particular Sans can't glow blue and blow things up. Yet.
You extract yourself from the blanket coiled around your shoulders, and hurl it to the ground for good measure. You remember where it originally came from. Alphys sure hadn't shown you any compassion when you needed it the most. Coffee? A blanket? Those were within her comfort zone. But speaking against her boss was not. She didn't even try.
You should hate that Noir skeleton. He brings nothing but pain. It's expected, and consistent, but it's still wrong. Life would be so much better for you, if only he didn't exist.
The world has reset. This time, you will do it right. You already know where everything is; where everyone will be. The knife is right where you left it.
You've been hurt plenty of times, but you've never thought of hurting someone before. It probably wouldn't have ever crossed your mind; not without me. So you'll need to follow my plan carefully if this is going to work.
You leave the break room, again. This time with a kitchen knife in hand.
You and I agree exactly on who needs to die first.
Even if you don't know Gaster's exact location, you know where not to look. So you loop back towards your own room; he'd been searching for you when you got caught, after all. The door to your prison is open – sure enough, complete with Noir skeleton.
Casually you hide the knife behind your back, and approach.
He steps out of your room, looking up and spotting you. "There you are." His mouth is the thin line you remember from before. Nothing's wrong on his perspective. "Come."
You reach with your free hand, eager to accept his invitation. There's no shrieking shoes this time. No pointless words. He will be the one lying on that table, writhing like a gutted fish.
Obediently you follow; he doesn't even notice that your other hand is occupied. While he's messing with the door, you make your move.
Your knife tears the black cloth on his side, barely scratching his bones.
Whether the pain or surprise gets him, he lets you go like he's been shocked, stumbling away from you and into the room. For the first time, you clearly recognize the expression of his wide-eyed sockets... shock. He's staring at you.
That 'attack' was pathetic.
You still don't understand how to hate.
You can't kill someone without such a simple desire. Weren't you paying attention to me earlier? Monsters are bound together by magic. It's the intention to kill that cleaves their soul in two. The power of hatred, the desire to erase their existence, overrides their will to live. Their souls submit to whichever will is stronger. If I was the one attacking... well, we wouldn't be having this problem right now.
The reins of your body are roughly shoved into my mind; your body lurches unnaturally as a result. It's like remembering a dream that I had previously forgotten. It had always existed, just outside of my conscious memory. Then the feeling was so clear, I wondered how I hadn't noticed before.
I feel the heat beneath your fingertips, the steady rhythm of your heart, smell the coffee clung to your clothes. It's not like being in my body. It's like being pressed up against a stranger. It's like being pressed against the glass, with my mirror image distorted on the other side. I'm so close. So close to existing beyond a consciousness and soul. Yet still, there's some barrier. Just a thin line that's thick enough to remind me that I'm not.
It had never occurred to me before that I could be you. I had always just been in you. But you handed me control. You... want this, even if you can't do it yourself.
I look up, to Gaster.
He's recoiled, taken a few steps back, nursing his side. There's no where to go in this room. I'm blocking the only entrance.
I take a step forward. There's a small delay between my thought of action and your body responding. Like a puppeteer that lifts the strings of its marionette.
Noir skeleton takes a step back. "Stop."
I'm grinning like a madman. I have a body. I'll take revenge. I'll feel the knife ripping through his bones.
Another step forward; he takes another back.
"I said stop," his voice wavers.
Instinctively you want to, but I have too much control to even waver.
"But why?" I test out your voice. It's unnatural. Doesn't sound right. But God, I can speak.
He can't do anything to delay his death. I spring, the knife flashing quickly. Your body might be that of a child. But my determination to kill; that's true. My hate pierces, ripping through his bones like they're made of brittle calcium. Aiming at that white soul beneath them.
He screams beautifully, crumpling to the ground; his very soul trembling. He'll disappear soon, but he's not positioned right. I grab his hand, like how he would take you, dragging him on the ground even as he cries. He's starting to disintegrate, powdery dust running through my palms, as I hurl him onto that damn metal table.
The bones are all but gone, my initial dream of dragging it out ebbing quickly. Pain is such a great equalizer. You might not be able to be a real person, but you can bring everyone else down to your level. He's in so much pain right now I bet he couldn't even tell you his name.
Gaster's clothes sag, losing the form that once kept them. My main regret is that monsters can't bleed like you. The beautiful red colors are hard to replace, even if his dust glimmers.
You have an idea and I follow with my hands, taking out the bottle of ketchup that Sans had given you, and unscrewing its cap. "Ketchup makes everything better," I say your words which you got from someone else.
The bottle tilts to the dust-laden corpse, marring Noir skeleton's perfect black and white. It's messy, doesn't quite match in texture or color; graffiti on a work of timeless art. But his dust sticks out like sequins beneath the mess.
I laugh, hysterically. It's so wrong. These two things don't match.
But he's gone. I got revenge, and you don't have to be scared of him anymore. He doesn't exist.
Now, for the others...
The door bursts open. Probably a result of the rather loud death cry Gaster had made; someone has come. You expect Alphys.
When I look up, it's the Sans skeleton. He's frozen in place, door wide open. Watching us, with the ketchup bottle still in my hand (a few drips dribbling out), over the dust of his dead brother. My smile fades. Our eyes lock.
It's his fault that I'm trapped here.
This limbo world between life and death, a purgatory that reminds me of everything I'm not.
There's no apology, no hope for the future, no action he can take that will fix this.
The ketchup bottle drops from my hand, clattering on the tile floor, shattering the painful silence. He flinches and breaks his gaze, his foot twitching slightly. Almost like he's about to run. He's always been scared of you, even if he said he's not. Because he's seen my potential within you.
I take a step forward.
Your presence presses against my mind, but you're the one on the outside now – you can't tell me what to do.
His posture changes, takes a deep breath, and meets my gaze again. His eyes are more sure; stronger than just moments before. "ok, kid. you didn't like him. i get that. but he's family. just cuz you don't care, doesn't mean i don't."
Another step closer.
"but murder? really? that's not how people solve problems. i don't know how you even reached that conclusion. thought you woulda been distressed in other ways first, maybe hit a few inanimate things, cry, uh, tell me or alphs, or, uh..."
Still. Closer.
He's sweating. "hey, put that knife down, ok? makes it, um, kind of hard to talk. you... remember who i am, right?"
So close. Mere millimeters away.
Your mind wraps itself around the reins of your body, but I won't let go. Why do even care? He's your captor too. But you think he's 'kind,' because he showed you basic human respect. That's not a choice; that's something that should exist innately. Sympathizing with your captors; they have a special term for your kind of sick mind: Stockholm Syndrome.
You can't be a person. He's right. But. You can bring them down to your level. And pain is the greatest equalizer of all.
"I remember." I ignore your clawing mind, clutching the knife tighter. "It's your fault I'm not dead."
The knife rips through bone.