Undertale and their AUs
93 stories
Inked in Bone by Firehedgehog
Inked in Bone
Firehedgehog
  • Reads 321
  • Votes 39
  • Parts 9
Inktober 2025, An Ink themed moth of stories/one-shots/drabbled. not taking donations for this one unless your in my private RP server. But you can all join the other one
A Splash of ink by philippaki
A Splash of ink
philippaki
  • Reads 44,722
  • Votes 3,826
  • Parts 96
Every child requires care and affection in order to thrive. So what happens when one is born alone and spends centuries by themselves? "Ooo! What does this taste like?..why does my mouth suddenly feel so tingly?" "Spit that out, right now!" ....the end result can be rather 'interesting' to say the least ~~~~ OC Babybones Paperjam, who after years of being alone finally meets other monsters. He has a great time! Everyone else is much more alarmed by the feral child.
I'm Killer Sans? Am I getting taller or what? [Reincarnation] by AbyssSh3ena
I'm Killer Sans? Am I getting taller or what? [Reincarnation]
AbyssSh3ena
  • Reads 14,823
  • Votes 618
  • Parts 7
What should do I now?... Hold on... I can change this story for the better ending! Buuuuuut I can't even save Dreamtale but I can save the two apple twins bonding's, that would be great! I should probably change my nickname instead of Killer sans...
Lightbringer Of The Multiverse by Lxzaruss
Lightbringer Of The Multiverse
Lxzaruss
  • Reads 46,262
  • Votes 1,864
  • Parts 17
Formerly known as, "Becoming the Dream of the Multiverse". Book cover is mine. A mistake made by the creator, a wish that was never ever bound to happen. "Huh?" "I'm not your brother." "What?!" "I'm not your brother, Nightmare." Enjoy this book while ya can~
Given An Unwanted Second Chance by UndertaleFanatic981
Given An Unwanted Second Chance
UndertaleFanatic981
  • Reads 43,948
  • Votes 2,871
  • Parts 52
(TW: unaliving thoughts and memories at the beginning. It gets better over time, don't worry! Trauma is difficult to overcome...) You didn't want a second chance. You didn't want to survive. You wanted the sweet release of death. But it seemed like the universe was far too cruel to allow you even that. It took away your memories, your free will to choose whether you live or die...hell, it took the one thing in life you owned! Your own name! And now it seemed like you had to live yet another cruel life, doing things you never wanted done to others. But...at least you could do things your way. Maybe this second chance wouldn't be so bad... (Reincarnated as Nightmare Sans, but unlike other stories, you have no clue what Undertale even is) (WE REACHED NUMBER 1 IN THE UNDERTALE TAG YOOOOOOOO) (9/13/25)
reborn as killer sans oh this will be fu- wait were mentally unstable  by Moonwolf_230
reborn as killer sans oh this will be fu- wait were mentally unstable
Moonwolf_230
  • Reads 5,490
  • Votes 361
  • Parts 28
so I oh ways want to make a reborn as killer sans, but we're mentally unstable, of course, due to the rest and our past memories, which we can't remember what we were anyway! We know everything and everyone, so why not mess with them. This going to me fun!!!
Raised by Destruction by UbaLala9
Raised by Destruction
UbaLala9
  • Reads 3,813
  • Votes 240
  • Parts 7
Adopted from Firehedgehog. Reapertale Asgore deems Goth to dangerous and throws him into the void... or rather antivoid. Now Goth is Error!Goth and being raised by Error
Inky Mistakes. ( Reincarnated!Reader) by Marbet_1
Inky Mistakes. ( Reincarnated!Reader)
Marbet_1
  • Reads 15,512
  • Votes 770
  • Parts 15
~I don't own the characters, or images, but I do own the plot and headcannons, but if I did own anything popular.. I would've been famous by now.~ [○○BEINF REWRITTEN○○] Someone was thrown into a multiverse, and not just a random sans, It was THE protector of worlds - Wait - GOD OF CREATION!? They are now meant to keep the balance while fighting the terrible memory, the OG plot line, and any other multiversal interference. Now all I gotta say is... They are definitely doing a better job than any other selfish, Souless ink will. "Heya, I'm Ink, But not YOUR~ Ink, So...Hi!" "WhAT- Cross, you're not coming over to my teaparty!? CrOSS, I MADE BISCUTS!!" "Yeah...buddy... I don't give a [YOO-HOO] about any of..*Gestures to ■■■■ whole body* all that." "Best friennnnnd~ I'm here for ya', I may not understand emotions well... but I can say, right now, I do feel like you need me... And I'll be there... No matter what!"
Reborn as sans from UnderSoul  by KarmaAkabane425
Reborn as sans from UnderSoul
KarmaAkabane425
  • Reads 73,057
  • Votes 2,435
  • Parts 15
I was reborn as sans from my own made up au. How did that happen? I have no idea. Luckily I was still a kid so I didn't have to act like how I made sans to act like but maybe having that act on will be amusing? And wait how did I end up in undertale with my brother and dad and..other sans and papyrus? What exactly happened next? Well you'll just have to read my own story. (Also I made that up as far as I can tell. I don't think I've heard of an au called undersoul before so yeah..different things will happen and begin and possibilities of different personalities etc) different things and yes I made it up and it's not like it's real so I made up the stats for them etc.
Mama Fragment by Firehedgehog
Mama Fragment
Firehedgehog
  • Reads 273
  • Votes 28
  • Parts 4
A Glitch Goes weird, and Fragment finds himself not glitching into others. Then a new fact leaves them shocked, somehow Fragment is pregnant...except he's never done the deed Fragment by @fragmentedtale-official-blog @quackysmackk but story by me. Using y insomnia to try to write this idea XD No idea if I'll continue or for how long. Original posts on Tumblr