Underfell Sans x Skeleton Reader

New person?

A few days had passed since Sans had asked you to be his girlfriend. Things have been going pretty well since then. Papyrus stopped being that harsh to his brother, probably because everytime he had tried to do anything, you would let your eye flare up, smiling at him insanely, reminding him of your little fight. He'd always stop whatever he was doing to his brother, afterwards you'd give him an innocent and sweet smile. Other than that things were pretty calm in the skelebros hous. You would accompany Sans most of the times when he went to work but there were some days when you just didn't want to stay at the station doing absolutely nothing. You'd stay home and watch tv, sleep, text with Sans or go outside to get to know your way around better. Today was one of those days. You had left the house a few minutes ago, covered in a long jacket, a (f/c) scarf and an equally colored cap. You had already left Snowdin and you were in warmer but still chilly place. It almost looked like the place Sans had brought you to for your date. You've been here before but you forgot to ask the name of the place. You knew were you had to go towards hotland but there was another way you hadn't used. So today you wanted to see where that lead to. It was a rather hidden passage way, you weren't even sure wether other monster could see it but either way you did and you were going to find out where it led to. Uppon walking in said direction the surrounding air changed. It became cold and repulsive. The thought of backing out crossed your mind, but your overwhelming curiousity got the better of you, so you headed straight forward into possible danger. It didn't take long  to reach a door in the wall, the air getting colder and scarier as you got close. Backing out was now a big thought of yours, screaming at you to not take a risk. But at the same time the curiousity grew. No risk no fun, right? You gave yourself a push, grabbed the doorknob and twisted it. The door opened with a loud creak, revealing a semi dark room with something in the middle. It was something black and a little bit of white. It seemed to be moving a little or at least to be alive. Fear was acting up inside you, afterall you were in a dark room with a creature in the middle of it. Fear and regret started settling in your bones, almost getting you to leave this place again. But before you could open the door again to escape, you heard something. Something you hadn't heard in a long time. It was a slight whisper but you knew what it was and it made you freeze in place, only to listen wether it would come again. It did, only a little louder this time. You were right with what it was. Wing Ding! You had learned that language ages ago but you could still use it. And what you were hearing, was that language. You turned your head to the side. The creature hadn't moved. Hearing it being able to speak said thing made you calm down a little and returned your bravery and curiousity. You let go of the doorknob and turned around but didn't go any closer to the creature. It had been a few years since you last spoke Wing Ding but the few words you understood made you realise that he wasn't a threat. At least that was what he said. Carefully you approached him. He didn't move. Once you were pretty close you decided to talk aswell, of course in his language: „Hello?" He stiffened and went silent for a few seconds, before he spoke loud enough for you to hear and understand: "Who's there?" He sounded more tense than before. „My name's  (Y/n). Sorry if i intruded, it wasn't my intention." Upon hearing and realising that you were speaking his language, he slowly started turning around. Now you could see him fully. He was a skeleton type creature with black clothes covering most of his bones except his hands and his head. He had a long crack from the top of his skull to his left eyesocket and a crack from his mouth to his right eyesocket and his hands, they both had a giant hole in the middle of them. „You." Your attention turned back to his face, his mouth not moving while he spoke: „You understand me?" His voice held curiousity, disbeliefe and amazement. You gave him a little smile: „Yes, i do. I learned Wing Ding a long time ago. He studied you a little bit before speaking again: „My name's Gaster." Your smile grew and you reached out your hand towards him: „Nice to meet you Gaster." He hesitated at first but slowly reached his hand out towards yours, eventually grabbing it. You shook it slightly, not wishing to scare him. "Why are you here?" he asked after he let go off your hand. "I was just walking around and found your door in the middle of nowhere. So i got curiouse. Sorry if i'm bothering you." He kept his gaze on you, not saying a word. It was starting to get uncomfortably awkward. "Do..Do you want me to leave?" "No, you can stay." Only now you took the time to look around, his room was dark and it seemed like he was the only one here. All alone. How long was he alone in here? Now you were starting to feel pitty for him, even though you had just met him. His white eye lights folowed you closely, reflecting curiousity and interest. You wanted to ask him why he was in here in the first place but you didn't know wether it was a sensitive subject for him. All you could do was try: "Can i ask you something?" "You just did." The joke surprised you but you started giggling soon after. Sans was the one who always made that joke, at every given opportunety. Half giggling you got out your chosen words: „Did Sans teach you that one? Heh." Uppon hearing that name he froze, getting tense again. „You know him?" He was still not answering, as if he was remembering something, being lost in his thoughts. „Yes i know him." He now locked his eye lights with your own: „How comes you know him?" He was sounding a little more aggressive and demanding. „Well, i'm his girlfriend. That's how i know him." His eye sockets widened, clearly holding a great amount of surprise. „Girlfriend?" His voice was now quieter. „Yeah, he asked me a few days ago." „How is he?" „He's fine. Just like Papyrus." He was now filled with curiousity, for hours he kept asking questions. For an example how you two got together, how the brothers were behaving with each other and so on. You explained everything to him. You didn't know why, but he looked, sounded and behaved like he knew Sans and Papyrus. But whenever you wanted to ask he wouldn't answer you, eventually you stopped trying. Hours had flown by without you noticing but finally you looked at your watch. Shit! You spent 5 hours here, Sans was long home, probably worried sick about you. You quickly said goodbye to Gaster and teleported to the front door of the skelebros house. Sans was going to be mad. With a long sigh, you twisted the doorknob, opened it and stepped inside. 

(Heya. I'm done with another chapter. Im so sorry it too so long but our dick teachers wrote tests in the last week before the holiday. But now i should be able to write chapters more often and publish them aswell. I'll do more chapter i promise but, sadly, the book might be coming to an end. I want to focus on my other book aswell. I'll definetly write more pages but i don't think it will last that much longer. Oh and quick question should i do like a christmas special in this book, of course it won't be relevant to the story. Well thats it for now. See yall in the next chapter, hopefully. Till then, BAI! Wish yall great holidays!)