Undertale Sister Scenarios

"Like Underfell, but a different AU."

My Lazybones Sans X Female Reader

So you are a sweet and shy 15 year old girl who lives with her mother and father.Your Mother and Father have decided to take you to a trip to Mt.Ebott for a family vacation.Once you got there you decided you've wanted some alone time even though your father disapproves your mother convinces your father to let you expl...

When Worlds Combine ~ Sans X Reader

Frisk was a good friend of mine, despite the age gap. About a week ago, they disappeared, only recently found. It wasn't long for Monsters to return as well. I, in all honestly, am scared. The world will be changing, and change never comes easy. Frisk seemed happy, though, in fact so far it's been okay. Frisk introduc...

Angel (Mafiatale Sans x Reader)

(Y/N) is a local jazz singer at Later's Nightclub. While singing she meets some monsters, and it all turns crazy.

A Little Bonely (Sans X Reader)

Monsters always fasinated you. Ever since Frisk broke the barrier and freed the monsters, humanity didnt take it too well but they are slowly getting used to it. Slowly. Very...slowly. (btw Chara is depicted as a female in this story, and so is frisk. Dun be triggy) HEY ALL! This is my first fanfiction EVER! so dont j...

At the Surface (Sans X Reader)

The monsters have finally made it to the surface and have been legalized to roam the surface as they please. The first couple of months have been spent as a paradise where humans and monsters have lived in peace and happiness. But as we all know, humans tend to be afraid of what they don't understand and the appearanc...

Pyromaniac Reader X Grillby

The reader is a patient at a mental hospital who loves fire and just can't stop burning objects, animals, people and even yourself. You just can't stop as your mind is dying, losing your sanity. You were abandoned when you are just a baby. While no one came to visit you made you alone. Unable to control nor feel prope...

(Sans x Reader) When Two Souls Meet

Sans has lived through countless timelines. He's seen the kid make friends with everyone, only to give up in the final moments. He's seen the kid killed, over and over and over again. Sometimes, he'd even done the killing himself. And no one ever remembers. Not even the kid herself. It's an exhausting cycle, one that...

Unexpected Love | Sans x Reader

You climbed the famous Mt. Ebott to prove to a group of your friends that humans don't disappear when they go up the mountain. While walking around the peak, you trip over a root in the ground and fall forward, expecting to hit the ground. Instead, you were met with open air. As you fell down the large hole, you let o...

The Red Scarf (Papyrus x Reader)

It's an x reader what else is the to say about it.

AU HighSchool x Reader OneShots

[Warning!] This Is a Book of AU characters x reader stories and may contain strong language in some of the stories along with sexual moments and perhaps Lemons! If you do not like any of the following listed do not read this! As for everyone else enjoy ya little sinners! xD and make sure to comment requests of an AU C...

*DISCONTINUED* Can you hear me? [Sans x Reader]

*Discontinued* This is the original version of Can You Hear Me? in it's unedited form. Monsters were back on the surface! But not everyone was happy with the change... though you aren't one of those people! Happy as a (relatively) popular singer, you were oblivious to the growing discontent. That is, until you met Met...

Prisoner of War (W.D. Gaster X Reader)

You are one of the few humans with magic during a war between you and the monsters. (Pre Undertale) Instead of killed you wind up captured by the monsters where you meet a scientist and doctor W.D. Gaster. Cover... I drew it myself this time

Unexpected Love: Return To The Surface | Sans x Reader

This is the second story to "Unexpected Love" so if you haven't read the first book you should probably read that first so you aren't confused. But anyways, enjoy! You wake up on the cold floor in the old lab that Alphys had found. You felt strange and the only life form that you could find in the Underground was Char...

Kind Of Comical [Sans X Reader]

//Undertale High School AU. Your typical High School story where you're the new girl~ //Except monsters and humans are together too. Involves time travel in later chapters. Never wrote an Reader insert before, so spare me! "You look lost there, Kiddo." A deep smooth voice caught your attention and you turned your h...

The void in my heart (Gaster X Reader)

You're a human girl, living on the surface with Frisk, who is your younger sibling. You one day find two children, who's been chased away from neighborhood to neighborhood. And with you're kind soul, you couldn't leave them to live in the streets. You take them in, and meet their father. But will one day, lose them, b...

Papyrus X Reader

WARNING: Not thinking about kids with this one. So don't let kids read it. Yea.

Scientist - GASTER X READER

Hi guys! So this is actually my first time writing a adventure story (and xReader), so I am kind of sorry if it looks crappy!! ****** A long time ago, people were missing when they climb up Mount Ebott. They say there was magic, got lost, or even died. But when you discover the secrets of the mountain, you will get at...

I Can Hear You. [Sans x reader]

This is a collection of chapters from my [Sans x reader] fanfic, Can You Hear Me? but from Sans perspective. Before reading this, I suggest you take a look at the main story, as this one will be based on the votes I get for the different chapters and probably won't make sense otherwise. It's been a few years since the...

Error!Sans x Reader {[(Under Editing)]}

A special human is going to need all the help they can, when a certain child is trying to destroy an underground community of monsters, a secret group of glitches, and the one who can harness the power of every self they are.

The Circle LOVE

AnyUnderTale sans and papyrus function is all in here even X Reader Also have~ so hope you enjoy reading （＾ｖ＾）

Gaster x Reader

Pretty self explanatory. This takes place after the Pacifist route in Undertale. Through determination, Frisk was able to bring back Chara, Asriel (Asriel is Flowey per say), and Gaster. I believe that Gaster is the father of Sans and Papyrus. I also don't believe that Chara is evil. The monsters are on the surface, a...

Mafiatale!Sans x Reader

You're a 19 year old girl (change it to boy if ya want). You steal, kill, and are a major criminal. You also have a little posse. You are the leader of a group of two other girls that are also criminals. One day, you take on a task allowing yourself to meet your idol and his friends. But what if you developed feeling...

Gaster AU x Reader ONESHOTS

Let's get this over with... HIGHEST RANKING: #35 in Fanfiction June, 23, 2017 ALL IMAGES USED ARE NOT MINE! Cover was made by Bunnymuse on her Tumbler (I think). Bunnymuse Tumbler: bun_bunmuse (?)

Hey, Doll | Gaster!Sans x Reader

Alone in a condemned world where monsters and humans fight for power constantly, Y/N survives off of the wood's riches and the small scraps of shelter she can find in ghost towns. Allies and friends have come and gone during the war, either killed or have parted ways. It's not all that bad. She could be dead, after al...

Undertale little sister

You are Sans and Papyrus little sister (Y/N) ( sorry if it is bad this is my first story ever so I hope you like it)

Underswap papyrus x reader

HOI! This my first us!papyrus x reader so do enjoy it, so good day reader-chan~! (=•w•=) Cover by: me Picture by: velka

Undertail Smut [DISCONTINUED]

This is my first book, hope you enjoy :)

~Why do you care~ [Underfell Sans X Reader] [•COMPLETED•]

Warning: possible swearing, inappropriate humour, perhaps lemons? Idk. Just stop being a goody two shoes and enjoy the book, kid

(Underfell sans x reader (female)) UNDERCOVER

You're a human that has fallen into Mt. Ebott on the year where all humans dress as monsters...Halloween. So how will the monsters know if you're a human or not?