Gaster AU x Reader ONESHOTS

Underfell x Daughter! Reader

"Sans, Papyrus, where are you jerks hiding?" You asked as you walked down a snow path. You suddenly heard crying, you looked around until you saw Sans. "Sans..? Sans!" You teleported to him and knelt beside him, you saw the reason he was crying. Your eyes widens as your pupils shrank at what he was holding.

"P..papyrus..?!" Sans looked at you with red tears in his sockets. "I... I tried to stop them... I..I really did." You hugged Sans and shushed him. "Sans... It's ok. Shhh... I will take care of this." Sand hugged you back and whimpered into your shoulderbone.

You teleported the both of you into his room and on his bed. You pulled away from the hug as Sans clutched to the scarf. "I... I never got to tell him h..how..." "Sans," your oldest brother looked up at you as you took in a breath, "I'm giving the human what they deserve. Stay here." Sans nodded slowly as you were about to teleport.

"Wait!" You turned around before Sans wrapped the red scarf around your neck. Sans then hugged you as if this was the last time he'd see you. "Please come home." "I will."

Sans let you go before you teleported to Judgement hall. Someone could say you were p*ssed, but that'd be an understatement. You were ready to tear the human apart. Not only did they kill Papyrus, they broke Sans. You had it, nobody messes with your family without answering to you.

You started to hear that human walking towards you. You snarled as your eyes glowed a dangerous red. "So, the human finally comes? Do ya feel proud of yourself?" The human kept walking as you stood straight and in their way. "Any point to this, why kill every one?"

The human finally stopped walking, you took a breath before you smiled in a dangerous way. "Why go through all of that trouble to get me maaaaad?" You teleported and stabbed the human's head with a flaming bone, you then teleported back to your original spot. The human's soul broke as you growled.

You weren't let the human get their punishment kindly. You kept killing the human with your fire-bones and Gaster Blasters. You finally decided to show your true power.

"💧☟⚐🕈 ❄☟☜ ☟🕆💣✌☠ 🕈☟✌❄ ☟✌🏱🏱☜☠💧 🕈☟☜☠ ✡⚐🕆 💣☜💧💧 🕈✋❄☟ ⚐🕆☼ ☞✌💣✋☹✡📬"

You knew that voice, it was your dad. You nodded, knowing your dad could see it, before summoning large flaming chains. The human was lifted into the air and thier limbs were wrapped by the flaming chains. "This is what happens when you hurt my family, you little b*tch."

You pulled on one of the chains, the human screamed in pain as their arm came off. You then pulled the last three, leaving the human helpless. You walked up to them and held a flaming bone in your hand. "Next time, consider the consequences." You stabbed the human before seeing their soul break.

You teleported home, covered in blood and sweat, to see Sans cooking something. You knocked on the wall gently. "(Y/n)!" Sans hugged you, you hugged back as you sighed in relief. "Y..You killed the human..? Right?" You nodded and rested your hand on his shoulderbone.

"Here," Sans lifted you bridal style and laid you on the couch, "I'll get you something to eat." Your breathing was deep and slow. You could see your father looking at you and smiling. You smiled back as you controlled your breathing.

You have never felt so much pride...