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1. Red on the Walls by MsMK

   Fandoms: Undertale (Video Game)  

   • Mature
   • Creator Chose Not To Use Archive Warnings
   • F/M
   • Work in Progress

   03 Nov 2021

   Tags

   • Creator Chose Not To Use Archive Warnings
   • Underfell Sans/Reader
   • UF!sans/Reader
   • Underfell Papyrus/Reader
   • uf!papyrus/reader
   • UF!SansxReaderxUF!Papyrus
   • UF!sans - Character
   • Underfell Sans - Character
   • Reader
   • Cheating
   • Anger
   • Teasing
   • Dry Humping
   • Swearing
   • light Violence
   • Biting
   • Marking
   • Underfell
   • Underfell Sans
   • Reader Is Not Frisk
   • Reader Is Not Chara
   • Revenge Sex
   • forgiving a cheater
   • Submission
   • dom reader
   • Upperfell
   • Angst
   • Broken Heart
   • Soul Sex
   • Aftercare
   • Threesome - F/M/M
   • Polyamory
   • Cuckolding
   • Oral Sex
   • Voyeurism
   • Smut
   • Shameless Smut
   • Fluff
   • Fluff and Smut
   • Death
   • Reader Death
   • Loss of Soulmate
   • Angst and Hurt/Comfort
   • monster hybrid baby
   • MILF
   • Cancer
   • Ssiyc bonus
   • Sub Papyrus
   • Dom Papyrus
   • Best Friends Turned Lovers
   • Masturbation
   • Misunderstandings

   Summary

   One Shot Series.
   Underfell: Sans is the best thing to ever happen to you...until the day you find him with another woman. When he refuses to let you leave, you have to decide whether you should forgive his transgressions, punish him, or both.
   I've turned this into a series of One Shots about the Fell bros, Ch. 1 & 2 are alternate endings so I will keep the same summary.
   Smut chapters marked as *

   Series

   • Part 2 of One-shot Collections

   Language:

   English

   Words:

   96,240

   Chapters:

   38/?

   Comments:

   977

   Kudos:

   1,903

   Bookmarks:

   248

   Hits:

   51,637