i won't let you leave me【Yandere!Sans x Reader】

Acceptance and Rising Resentment

            You looked at the glowing blue sweat trickling down Sans' skull, then turned to stare at Gaster. If you weren't so used to seeing horrifying things you would probably faint from the sight. It was so strange–he looked like a photo struggling to render, body melting and glitching with the space around him warping.

Before, you stopped Sans from intervening, because you knew Frisk would figure out how to calm down Papyrus and Sans getting involved would've just made it worse. But you hadn't known that Gaster would be like this. Sure, he was glitching before, but you thought it was from Papyruses magic. Now all you could do was stare.

Uselessly.

You looked at Sans. You didn't want to touch him when he was using so much magic. The hand outreached and pulling Gasters' soul to the ground was shaking, the magic covering it lighting up and darkening randomly. Squinting slightly while staring at his eye light, you knew Sans was starting to give up. There was a strange hopelessness in his weak smile, along with the less amount of magical output.

Gaster remained struggling, and you wracked your brain for some kind of solution. The problem was the pain in his soul, and that's why he couldn't stay corporeal. Gasters' soul wasn't completely attached to his body, so the more agitated his soul was, the more likely it was to try to return to the void where it had been for so long.

"...Holding him down isn't working." You murmured, biting on your nail. You turned to Sans, before resolutely reaching forward and resting a hand on his face. Sans startled, eye light flickering to you, the hand keeping Gaster stable starting to fall down. "Listen to me. You have to bind his soul to his body."

Sans grimaced with hesitation and uncertainty. You titled his head more towards yourself, staring deeply. "I believe in you. I know you can do it. You've done something similar to me before and in a much more complex way. This will be easy." You pushed away your own bitterness, ignoring the thoughts regarding your own entrapment. You held his gaze confidently, seeing his flaming purple eye light continuously flicker. Finally, he turned back to Gaster and stood up. He gently placed you on the ground and made sure his barrier around you was impenetrable.

"I love you." You smiled sweetly and gave a thumbs up, "Do your best!" The cheesy lines still managed to soothe Sans, who showed a shaky grin in return. He left his own barrier, walking forward and breaking through Gasters. Still sweating and obviously exhausted, Sans struggled to walk around the mass of chaos that was Gaster's body. Finally, Sans reached out and grabbed the blackening soul, grasping it gently with both hands and heaving a sigh.

You blinked, not able to see exactly what Sans was doing. Instead, you checked up on Papyrus and Frisk. Papyrus was looking forward was a genuine concern, but still tightly held onto Frisk in his arms. Your mouth twitched.

A loud cry of pain shook you from your thoughts. Gaster was wailing; the sound of his voice crackled and left you very uncomfortable. The hairs on your body stood, goosebumps erupting all over. You shook it off and looked for Sans. He was doubled over. You couldn't see what he was doing to Gaster's soul. You prayed that all would go well. You wanted to think it was because you wanted Sans and Papyrus to keep their father, but deep down you knew the real reason.

Gaster could help you. Of course, he could help both skeletons, so that was also a big reason you hoped for all to go well. Everyone obviously needed some kind of guidance and Gaster was the closest thing to a parental figure they would get. Maybe Sans would listen to Gaster if instead of you when it comes to your concerns.

For once, god heeded your prayer. Gaster slowly began to reform, voice no longer out of control and crying out. Gaster collapsed onto the floor motionlessly, and Sans weakly gave a thumbs up for everyone in the room. Gaster lived.