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Mandatory Harry Potter AU by destroyerofvoidsss
Fandoms: Undertale (Video Game), Harry Potter - J. K. Rowling
03 Jun 2026
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Summary
" Nearly four years ago, if someone told him he'd be going to a school of magic, Gradient was sure he'd laugh in their face. He wasn't the social type, but he'd do it anyway, because it was just ridicolous enough, just insane enough, just fantasy enough that not laughing would look weirder."
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Author's self indulgent Harry Potter x UTMV x Human AU crossover fic made for shits and giggles. Warning in advance for mediocre writing.
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Honey didn’t mean to get involved. One wrong place, one wrong encounter and suddenly they’re working as an informant for the most dangerous gang in Ebott City.
Across the city, Viper works for the Red Ring—efficient, unseen, and ruthless. Jobs come and go. It’s just the way things are.
- Language:
- English
- Words:
- 8,755
- Chapters:
- 2/?
- Hits:
- 64
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You were kidnapped by the Bad Sanses gang because you apparently "stole" Horror's axe. All hell breaks loose.
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Where Killer!Reader goes through the what-ifs of meeting and romancing various Sans AUs
Series
- Part 1 of Nothing's New
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The first stranger looked like Sans, but his jacket was the wrong color and his smile was too sharp. The second looked like Papyrus, but he was far too rough and terrifying. Now, Grillby’s is filling up with shadows of the people you know best, and your own Sans and Papyrus won’t give you any help in the mystery.
As your health begins to fail in ways no doctor can explain, you’re left with one question: Why are they all here, and why does it feel like your life is the price for their arrival?
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Dread ate at poor Sans as he tried to find its source. Multiple stories spoke of a fallen monster whose tears were woven like strings, prophesized by dread. Before he knew it, Error raptured him, all in the objective to show just how wrong he was about humanity. Refusing to yield, it was now Sans's task to defy his captor not in a physical brawl, but in a philosophical engagement.
This work will be updated every 2 days until an arc is complete.
Series
- Part 1 of Undercosmos
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You and Sans had been working on this machine, and suddenly it works!
But now there are a bunch of skeletons appearing everywhere and you can't stop it.Well, you guess they're kinda... anyway!!
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Reverse harem with Sans and Papyrus aus. I plan for it to be a slow burn but it's my first time writing it soo....
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Dream wants to destroy the multiverse and reset it as something perfect and positive.
Ink refuses to let every flawed, chaotic, beautiful world be erased for the sake of one ideal reality.
Aka: a multiversal civil war with just a splash of Inkmare. (a lot of Inkmare)
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Be mindful that the tags and rating is subject to change with any new chapter added.
This fic updates AT LEAST on a weekly basis.Series
- Part 1 of The Gospel of Broken Things
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Being a creator themselves they hated the way that XGaster treated his creations but their wasn’t much they could do about it seeing as it wasn’t exactly real, but reincarnating into UnderVerse they were going to use this opportunity to beat some sense back into Ink, and make sure XGaster lost his life privileges and XGaster’s bitchass was going to pay, and his victims would get JUSTICE. But what was JUSTICE? And what was VENGEANCE? Could they make sure not to fall into VENGEANCE or would they even care if they did?
Also if they might be able to help out a pair of lovers along the way and see one of their favorite ships come to fruition, well, no one could blame them~
But can the others at least stop calling them kid!
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Dream had gone missing… Nightmare was worried, so he set out to find him and ran into a strange group of Sharks on his way.
(Unsure how many chapters it will be since I’m splitting it up randomly where it feels right to since it’s nearing 50,000 words and that’s… a lot to read in a single chapter.)
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“so, you’re uh…” the blue skeleton in front of Sans had an odd pinched expression.
“an advanced AI” Sans clarified and his social program hissed at him to relax his posture “nothin’ more an’ nothin’ less”
Sans’ analytics quickly gathered the expression of each skeleton monster in the room to come to the conclusion that something was off. He carefully noted the odd atmosphere as the chime of a directive made itself known.
FIND A WAY HOME
Something in him settled and the red circlet at his temple evened out to a mild yellow.
“you sure about that pal?” the first skeleton’s red twin said as he picked his golden tooth after a pause.
“my social programming’s pretty complex, it can be hard to tell i‘m just a machine” Sans tried not to let incredulity sneak into his voice—of course he was sure.
“THAT CAN’T BE RIGHT” a lighter blue skeleton said rather intensely and Sans’ analytics scrambled to see where he went wrong “YOU HAVE A SOUL. RAZZ CHECKED YOU EARLIER”
Sans blinked at the accusation.
Or
Sans is pretty convinced he’s a machine, everyone else is convinced he’s got issues.
Series
- Part 3 of Undertale Fics
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Killer was bored again. What does he do?
10:48 am
*kills u cutely* 💖💞🎀 added 8 people to Mentally Ill Skeletons 🗣️🔥🔥💥‼️
Yeah I. I started a chat fic. I am so sorry.
Genuinely have no idea whether this will be continued or not but I have hope at the moment
Nightmare (by Jokublog) - Mamanootmare
Dream (by Jokublog) - 🌟Dream🫶✨
Killer (by Rahafwabas) - *kills u cutely* 💖💞🎀
Horror (by Sour-Apple-Studios) - MAMAIMNOTDOINGDRUGS
Dust (by Ask-Dusttale) - hrngh soup
Cross (by Jael/Jakei) - *comically loud buzzer*
Swap (by the Undertale Community (?)) - The Supreme Swap 💠
Ink (by Comyet) - waitwhatwasmynameag
Error (by LoverOfPiggies/CrayonQueen) - GlitchInTheSystem
Lust (by NSFWShamecave) - Jealous? 🩵
Undertale by Toby Fox! -
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Summary
Disclaimers:
Several details in this fic are heavily inspired by 'Blue joins the bad sanses' comic, so go check that out
Canon innacuracies: Passive and Corrupted Nightmare are the same person, Ink is the creator and not the protector, Ink, Error, Nightmare, and Dream, are all gods, Blue, Killer, Horror, and Dust's specific au timelines were all destroyed, and i took liberties with how the void works. Also, no Cross sans will be mentioned, i don't know enough about underverse, and there will be some OC non-sans God/entity/things later on. The fic will be split into parts, each lasting nine chapters.
Schedule: Once every other week, on Saturday, Sunday, or Monday, and i will post art or a reference sheet with every chapter. Trigger warnings will be specified in chapter notes. I've never written for undertale before, so please let me know what you guys think :3With that said, the actual plot: After an injured Error crashes into Nightmare and Co's home, a close bond starts to form between the two gods, both forced villains. In light of Ink's attempt to kill Error, Dream finally starts to lose it, and Blue gets dragged along.
Average chapter length is 500-2000
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Children of the stars - NBATBAG Prequels by Ev3lyn (Candle_The_Cat)
Fandoms: Undertale (Video Game)
02 Jun 2026
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Prequel chapters for Nobody asks to be a god
I had these planned since before I did Novembmare, so these were always going to be part of the story. I'm putting them in chronological order, but they were not written in chronological order. Some are older, which means my writing style looks a little different. These will be marked in beginning notes.
Trigger warnings in beginning note for each chapter, and I'm reiterating that I'm not following Dreamtale canon, like, at all.
Original characters are the Voidlings, and various dreamtale villagers.
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The Multiverse is dying. The balance has been tipped too far and now it threatens to crash down around everyone. But Dream believes the answer to their survival lies with their newfound Destroyer.
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Nightmare notices lately there's been high influxes of negativity within the multiverse. Even stranger so, was how heavily concentrated they were within one AU. When the demigod of negativity finds opportunity to investigate, he didn't quite know what he expected.
It certainly wasn't this.
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(A/N: An f!god fanfic. Error comes in later.) -
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In which a deity comes to earth disguised as a human and gets tangled with a bunch of skeletons.
Athena had her own goals, her own secrets, and the skeletons had theirs too, but somewhere along the way, intentionally or otherwise, their paths just happened to cross, and whether they realize it or not, the more they intertwined, the more the foundation they built their facades on crumbled.
It was only a matter of time, really, before one of their walls collapsed, but until then, things are about to get real silly. Incredibly and stupidly silly.
[Has nothing to do with greek mythology; Reader sharing a name with the greek goddess Athena is pure coincidence]
Series
- Part 1 of Undercover Deity: The Series
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An execution.
The Multiverse demanded Nightmare Sans, the Guardian of Negativity, Leader of the Bad Sanses, his twin brother... to be executed.
Dream refuses to accept it.
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With everything they have been together for the last few weeks, Nightmare agrees to let Luna and Honey go out to get supplies for the growing number of residents within the Castle.
Who could have known the dimension the deity sends them to is one that will have past lives clashing and major secrets finally revealed.
Series
- Part 5 of Kaleidoscope
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“I found this notebook in Outertale. I think it belongs to Error.” The child explained as Ink began flipping through some of the pages. The protector stopped on a page in which he saw his name.
“Another fight with the damn ink stain. How does he always know where I am anyways?? I wouldn't be surprised if that weirdo was stalking me or something...”
Ink let out a snort as he continued reading.
“Oh yeah, this is definitely his.” He resisted the urge to read it all right then and looked back up at Core, “Say, could I keep this?”
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Ink gets ahold of Error's diary and slowly revelations are unearthed not only about Error, but Ink aswell.