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1. Best Friend's Brother by FandomWorld9728

   Fandoms: Undertale (Video Game)  

   • Mature
   • No Archive Warnings Apply
   • Other
   • Complete Work

   14 Jun 2025

   Tags

   • No Archive Warnings Apply
   • Sans (Undertale)/Reader
   • Papyrus (Undertale) & Reader
   • Muffet (Undertale) & Reader
   • Mettaton (Undertale) & Reader
   • Papyrus (Undertale)
   • Reader
   • Sans (Undertale)
   • Muffet (Undertale)
   • Mettaton (Undertale)
   • Non-binary Reader - Freeform
   • Reader-Insert
   • Reader is not Frisk or Chara (Undertale)
   • Puns & Word Play
   • Cussing
   • reader uses they/them pronouns
   • Reader Has An Anxiety Attack
   • Post-Undertale Pacifist Route
   • Undertale Monsters on the Surface
   • Protective Sans (Undertale)
   • Implied/Referenced Abuse
   • Awkward Sans (Undertale)

   Summary

   You had a serious problem. You had a big, fat crush on Sans. The only reason it was a problem... was because he was the brother of your best friend. How were you supposed to hang around him if whenever his brother came in the room, you were a blushing mess?

   Series

   • Part 1 of Sans/Reader Fics
   • Part 2 of Undertales Across the Multiverse

   Language:

   English

   Words:

   2,629

   Chapters:

   4/4

   Comments:

   11

   Kudos:

   45

   Bookmarks:

   7

   Hits:

   496