Undertale Theories

Reads 307
Votes 20
Parts 6
Time <5 mins

Reads 307
Votes 20
Parts 6
Time <5 mins

Hello.My first book....nice.Well all of these are either my theories or my opinion about other theories.Either way it's still theories!!!Wow,am I the only excited one here or what???Nah i'll keep writing : 3All Rights Reserved

undertale undertaletheories

Table of contents

6 parts

Content Guidelines

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Ask and Dare the Sanses!!! (And Me- ) by Undercorn2

(I'm leaving everything as-is, but this book is old and strictly only still here for memory purposes. If you wanna read you can but it's really bad:P) Yeah yeah, another one of THESE books, yada yada. Just saying, this is not a normal book. Wow, so original right? I am obsessed with plots, so around 40-ish chapters is when everything just FALLS apart. Oh, and yeah... uh... be warned. DatOneArtKid and I-approve-this spams, and i reply to any comment. I will flip if there is another reader cause This is the MOST I've ever done and gotten this much. So like, just know. Oh, and ships........ Golly. You can ask to be shipped with someone, and i'll tell you if they're taken or not! Under is me, by the way, lol. Undermare. Bai! Oh uh... Welcome! I hope you enjoy your stay at the A+D hotel! ~Under~

Into The Game >> (Sans X Reader) Undertale FanFiction by Melody4164

It was just a normal Saturday. (Y/N) was playing Undertale for the millionth time. She was obsessed. (Y/N) had played all of the routes. True Pacifist, No Mercy/Genocide, Neutral. She experimented with killing certain characters doing different things. Then, as (Y/N) started a new game, she felt a falling sensation, as if she just fell out of her chair. She blacked out soon after. When she woke up, she was lying on a bed of golden flowers. She knew this place. (Y/N) was in the game. She had taken the place of Frisk and was in the Underground. •Disclaimer I do not own Undertale. It belongs to Toby Fox. I do not own you. You own yourself. I do not own the cover or any of the pictures that will show up in this book• *If you're reading this as a guy please just change the pronouns to he/him/his. I find if a lot easier to just put female pronouns. Thanks! :3 *

$Lust x Horror {Sanscest} (Plus Fontcest, Sanscest, & Pappycest Oneshots) by Mavi_Sumukler$

HELLO FELLOW SINNERS~ this is a smutty/fluffy fanfiction based of plots I have either made or was randomly told but anyways be sure to request thats what keeps this book going and also keep in mind there will be slow updates sorry 😅 Enjoy~ ~Mavi Sümüklər

A Strange Feeling (Sans X Reader) by Sak423

Do not expect consistent uploads as I am a college student🙃. This is rated mature because of strong language. You are a 24 year-old in college and have loved Undertale since the beginning. You enjoy all the aspects of the game; the story, the lore, the music, the backgrounds, and most importantly the characters. You've started having a strange, almost malicious feeling related to the Genocide run and that creeps you out. So, you start a pacifist run and after a while, you fall asleep. You wake up in Undertale and thus begin your new journey. Through your travels, the strange feeling comes back, but as a different emotion. Perhaps the only one that can help you with this feeling, is a certain punny skeleton. (I tried my best I'm not very good at summaries 🥲.) (Also I am so sorry for the kinda weird writing this is my first time writing a story. So I welcome constructive criticism.) Started: January 26, 2025 Ended: ???

Fifty Shades Of RED | Underfell Sans X Female Reader by darkpsychoangel87

You are in a contest to become part of the Undertale Multi-universe. The first part of the series, you are part of Underfell. Will you be victorious? Of course you will, or there wouldn't be a story. Find out what happens. If it goes well, or I can think of ideas I will do the other Sanses and Swap Papyruses. Note: This story contains: Sexual content, violence, swearing, and crude humor. Note: Also on my end, it says it only has 9 parts... there are 16... Well 15, one is an update.

Undertale Au's x reader 5 by Broken-fnaf-fan

Yes, here it is the fifth book! I went ahead and decided to make the fifth one now, new book, new ideas! Anyway, request are open, but give me some time to catch up with all of the other ones I have at the moment. Thanks! I don't own any of the AU's or art unless I say so, However the outcasts do belong to me! If this is your first one shot book from me, Welcome! Now if you've read all of the others then, Welcome back! (updates are random)

DONT READ THIS CRAP- it sucks please please please do not even touch the book. I'm writing a rewrite, and so far, the first part is published. It has lots more humor than this. Still go check out darksoulzycaliber. They're amazing. Your an artist looking for some appreciation. Just as you about to give up, you look to undertale for some Inspiration. But when the game glitches and you get stuck inside. You leave your old life behind, to befriend all monsters. This story's Nightmare was inspired by @DarkxSoulzyxCaliber he kinda has the same magic properties and stuff, maybe just a little difference in attitude. That's the only reason I put them there, but they are a great writer and artist so please go check them out!!!

The year is 20XX. A human has fallen from the surface world! She was running from her abusive home when she made it to Mt. Ebott. However, when she looked behind her to see if she was followed, she forgot to stop running. Needless to say she tripped and fell. However, she was not caught by the ground, instead she kept falling. When she landed on a patch of yellow flowers, she heard a voice. She began to freak out watching a figure approach her as she fell unconscious... Hello everyone! It's been a bit huh? Yup it's an X Reader fanfic! I myself read these types of stories because I'm a lil' lonely but also a lot of them are really good! However, when I went looking for Frisk x Reader stories I found that most of them were Male Frisk(/Chara) x Female Reader, or visa versa. I was looking for a Female Frisk(/Chara) x Female Reader. I didn't find many at all. Therefore, I have decided to write one myself. Hey guess what? THE COVER IS ORIGINAL!!! I actually did this one on my own and was proud of myself because I think it looks pretty decent! TBH I don't quite know what's in store for this one... I didn't plan this one like I did Danvid.........But Also Dadvid. So let's see how this goes together shall we?

Flowerfell Sans x Abused! Neko! Reader by Suki004

I made this book for @KawiiPotao6678 they have never read a flowerfell x reader so I made this book for them. But all you other people can enjoy as well. Sorry if some of the information on here is wrong I am not very familiar with the Flowerfell AU. I will look up what I can and learn more about it while making it. I will also fix what mistakes I have made because some people are so picky about spelling (not saying any names). I own nothing but the story!!!!!!!! I don't own you!!!!!!!!! I don't own undertale!!!!!!!!! I don't own Flowerfell!!!!!!!!!!! Nothing is mine!!!!!!!!!!!!!

Grouptale AU - Undertale Fanfiction by aquanell

{Can everybody PLEASE stop reading this awful story so I don't feel bad about deleting it?!} This is an AU where all 7 human souls fall down to the Underground at the same time. DISCLAIMER: Several things I have decided on for this fanfiction. Toriel and Asgore got divorced after the death of Chara and Asriel and Asgore's declaration of war. The human souls will be called by names I have decided on for them, not by their soul traits. (Cody and Clover are from the fangames Undertale Green (Kindness) and Yellow (Justice) respectively. The others are Hannah (Perseverance), Amy (Integrity), Echo (Patience), and Leo (Bravery). Chara is a ghost only visible to those that remember (I'm going with Sans, Alphys, and Mettaton (since the latter 2 probably have their research to gain clues of the past timelines. I'm not saying they remember everything, but...), as well as Frisk and the other fallen humans.

Ask and Dare the Sanses!!! (And Me- )

(I'm leaving everything as-is, but this book is old and strictly only still here for memory purposes. If you wanna read you can but it's really bad:P) Yeah yeah, another one of THESE books, yada yada. Just saying, this is not a normal book. Wow, so original right? I am obsessed with plots, so around 40-ish chapters is when everything just FALLS apart. Oh, and yeah... uh... be warned. DatOneArtKid and I-approve-this spams, and i reply to any comment. I will flip if there is another reader cause This is the MOST I've ever done and gotten this much. So like, just know. Oh, and ships........ Golly. You can ask to be shipped with someone, and i'll tell you if they're taken or not! Under is me, by the way, lol. Undermare. Bai! Oh uh... Welcome! I hope you enjoy your stay at the A+D hotel! ~Under~

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