21 - 40 of 4,551 Bookmarked Items in Alternate Universe - Underfell (Undertale)
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Summary
Over a millennium ago, monsters and humans went to war. As the bulk of monsters were sealed in the underground, some monsters stayed behind, continuing to fight for their brethren. As time warred on, a treaty was formed, calling the end to the war between the humans and monsters remaining on the surface.
Years later, the barrier sealing the underground is destroyed. Surface monsters, now fully integrated into society, take interest in finding their long-lost kin. A skeleton monster, in love with the idea of finding her soulmate, travels to the city in search of the last of her kind. And you, her best friend?
Well, you’re along for the shitshow.
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Интересно 💖🔁
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"Bless me father, for I have sinned."
The dim light coming from the opposite side of the confessional made you feel uneasy. You couldn't quite tell the shape of the priest, even though you knew he was there, listening to you.
"It's been three months since my last confession." You said fidgeting your thumbs while you tried to find the right words.
The priest cleared his throat, waiting for you to continue.
"I have been spending time with someone who lacks morals... has no respect for our religion and no concern for the people we help... nor me." You gripped your knees. "And I have been enjoying his company despite it all. Every second of it." You said bowing your head in shame.
The priest didn't answer right away. It felt like minutes had passed before he let out a deep chuckle.
"sister..." he purred, his voice deep and hoarse. "do ya really enjoy my company that much?"
You quickly sat up as you woke up, breathing rapidly while looking for him around the library.
But you were alone.
Series
- Part 1 of Poor little nun
- Language:
- English
- Words:
- 136,511
- Chapters:
- 18/18
- Comments:
- 338
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- 540
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- 130
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- 16,055
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Monster Sans x Nun Reader
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not started yet
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Ch7
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Standing on the edge of a waterfall, you contemplate your life and what brought you to this point. You had always been told that obeying and doing what you were told meant things would go well for you.
However, being titled the good girl, you were sure of one thing; that was a lie.
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Broke with little support, someone from somewhere in your childhood conveniently leaves you a voicemail inviting you to stay at her place, you take it. Where does that get you?
Stuck in a circlejerk of magical raging skeletons, but thats fine, you can spit back.
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11
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In order to summon a small version of your Soulmate you need few ingredients: Milk, a Love Bloom flower, a small fragment of your soul and a monster to perform the ritual.
You wanted to feel less lonely in your apartment.
You did not expect to find yourself with your hands so full.
I sometimes stream my writing, feel free to join! https://www.twitch.tv/ladyflame
- Language:
- English
- Words:
- 39,139
- Chapters:
- 34/34
- Comments:
- 1,010
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- 2,553
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- 507
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- 54,967
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Sometimes, you liked to imagine that Frisk was this kind and sweet because of you.
That, maybe, you had lived up to your promise of being the best sister you could be when they were first born.
That you taking the brunt force of your abusive father’s hits and drunk mother’s curses was worth it.You had protected them from the reality of your family and… you knew that you had to protect them now.
You were Determined… To stay Kind.
- Language:
- English
- Words:
- 241,088
- Chapters:
- 48/?
- Comments:
- 462
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- 1,823
- Bookmarks:
- 350
- Hits:
- 43,879
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Ch. 1
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Want to sex up a skeleton? Sure you do! Come on in and let's get boning!
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Prompt fills for Kinktober 2018, mostly used as character/relationship exploration for various AUs (UT classic, US, UF, SF, and HT). If you like your kink with a side of feels, you're in the right place!
Series
- Part 1 of Kinktober
- Language:
- English
- Words:
- 26,358
- Chapters:
- 32/32
- Comments:
- 581
- Kudos:
- 2,295
- Bookmarks:
- 254
- Hits:
- 76,930
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When you were ten years old, your parents sent you to stay with a relative of yours from Ebott. Their villa was situated up on the mountainside, and you loved to explore the forestry. One day the ground gave out and you fell Underground, and faced terrors beyond your imagination. You were missing for weeks.
After you managed to miraculously return to the surface, your parents were relieved - but deeply troubled by your 'delusional ramblings'. They were convinced you were 'crazy', and feared how that would reflect on their reputation. Your doctors advised sending you to an in-patient psychiatric facility, which is where you spent the next few years in intensive therapy and counseling.
15 years later, you're a young adult with a somewhat manageable grip on life. You keep your head down, attend the social events that are expected of you, and try to be as unnoticeable as possible. Your parents arranged a suitor for you, and you're to be wed within the next year.
That is, until, those monsters your parents and doctors tried to convince you weren't real suddenly crawled out from the Underground. And they're a lot different from what you remember.
[[Underfell!verse.]]
- Language:
- English
- Words:
- 402,017
- Chapters:
- 46/?
- Comments:
- 1,372
- Kudos:
- 1,007
- Bookmarks:
- 198
- Hits:
- 39,808
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46
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Bookmark Notes:
chap 44
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My Soul Found Its Place With You by SpookyBxtch for yeo_sin
Fandoms: Undertale (Video Game)
03 Sep 2025
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DeepC ripples, the air abuzz with a steady stream of their magic. Without an Encounter or active Intent to force the latent magic into the shape of an attack, the magic seeks the closest conductor; you.
It sinks into your skin and works down your arm and into your hand and through the petal — jittering from the feeling, you watch the paste crackle white, the magic sinking in and creating a stronger conduit for your own Soul’s passive magic to start funneling through. From where your bloom has been set, the strange substance begins to flush a deep purple-red shade, twitching and flexing and rippling in colourful waves.
Honestly, you should be forgiven for nearly screaming when the paste swells — with a thick, almost viscous gurgling sound, it swallows your finger clear up to the base knuckle. Shuddering with childish disgust, you struggle not to throw it off and squeal, the paste starting to go from red-purple to a pasty white shade the longer it clings to your skin, rapidly becoming thinner and more runny.
A final burble, a loud, wet pop.
And then…
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AKA: I have no self control and started another long-form fic despite knowing that I have undiagnosed ADHD-
Bookmark Notes:
ch2
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You never expected much from a speed dating night.
Three minutes at a time, a blur of strangers, and nothing worth remembering… until him.A sharp smile, a voice like gravel, an aura that drags her closer even as every instinct tells her to run. He’s the kind of danger you don’t walk away from untouched... the kind that leaves a mark.
This is what happens when opposites collide, and neither of them is willing to back down.
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Frisk sang for a living. She sang in clubs that were populated by mobsters, murderers and the most violent criminals her city had to offer. She honestly thought things couldn't get any worse until corruption in the form of a grinning skeleton came strolling into her life. His name: Sans.
She tried to run, but no matter where she went he was always waiting for her.
Chapter 34 finally up!
- Language:
- English
- Words:
- 226,958
- Chapters:
- 38/?
- Comments:
- 11,239
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- 28,985
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- 2,745
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- 1,073,865
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In a dog eat dog world, you just run a little sweets shop.
In a dog eat dog world, Papyrus is just looking for something soft to keep close.
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Ch20
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CH4
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Bookmark Notes:
ready for 6
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Bookmark Notes:
20
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C 14
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Summary
It's not that Y/N had a bad life, just one that wasn't very fun or fulfilling. When you meet Papyrus and Blue, everything changes. When you learn your twin sister, Edwina, met them, you fear you've lost their friendship as you had so many that Edwina wooed away. But, to your surprise, Papyrus and Blue were just the beginning. Through a series of events not of your control, you find yourself even more integrated into the lives of several skeletons. Some don't like you and some do, but that's life.
And your life will never be the same.
*currently editing all chapters* Chapters 10/46 edited
Series
- Part 1 of Duchess Soul Series
- Language:
- English
- Words:
- 161,953
- Chapters:
- 46/46
- Comments:
- 1,886
- Kudos:
- 2,101
- Bookmarks:
- 431
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- 57,412
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Ahhh crying
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It’s been a few years since monsters had escaped the underground. At first, people were overjoyed when the monsters were getting rid of the mafia, thinking that they would finally be free.
Only to have that glimmer of hope snuffed out as the monsters established their own mafia.
You tried to stay out of it all. Kept your head down, paid your dues on time, never looked towards any sounds that seemed suspicious. This life was rough. Luckily, there was always a certain feline who always cheered you up.
When your cat escapes your apartment, you’re beyond upset. Missing posters, posts online, asking your neighbors, you do anything to get your precious friend back home.
As weeks pass, you begin to lose hope that he’ll ever be found, only hoping he found a home with a rich owner rather than thinking about the possibility that he's dancing among the stars right now.
You nearly sob in relief when you get a call saying they found your cat. After talking to the stranger and agreeing on a pickup spot, you arrive with a smile, only for the thank you speech you had prepared dying on your tongue as you see just who found your fluffy companion.
The very monster mafia who had taken over your town.-
Bookmark Notes:
Chapter 2: Y/n gets his cat back and fell asleep in Wine and Coffee’s mansion (have not met yet)
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Wake up buried in snow, alone, and with no memories?
Check.
Kepp seeingg numbers, words, and text floating around every object and surface as far as the eye can see?
Also check.
Why does every person he meets say he needs help?!
His perfectly fine if you ask him."I wonder what determination taste like"
Note from the author:
This is my take on Fatal Error—a much more none canon, this isbt even OOC this is just straight up diffrent person with the same name, amnisiec version of him.
He’s also not fully canon-compliant in terms of power scaling and has and maybe different origin and personality.
It’s my reimagining of him.
Glitchy, lonely, and filled with questions, bad puns, power to blow up annoying people and some more puns.-
Bookmark Notes:
34
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Kiss Me, Kill Me (And a Secret Third Option) by Embrace_the_Deep (DefinitelyNotABee)
Fandoms: Undertale (Video Game)
28 Jul 2025
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Summary
What had Ink tried calling him again?
Someone named Killer?
As fitting as that name would have been for the previous owner of his body, he clearly remembered that he had been referred to as 'Sans' in the blurred bits of memories.
Maybe he was being mistaken for someone else.
He hopes he never meets this actual 'Killer', but even if they were some sort of shady person- skeleton- thing, that doesn't excuse kidnapping a stranger and chaining them to the floor of your home after nearly killing them!
With the most unimpressed expression he could muster, Quill forced the aching phalanges of his right hand into a wrist-up fist, and extended his middle finger.i.e. A self-indulgent crack-treated-seriously fic featuring isekai!Killer vs. the Multiverse. Enjoy!
Series
- Part 1 of The Third Secret Option
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Bookmark Notes:
21
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Summary
A bet is made. The bet goes horribly wrong. Red ends up in lamia!Edge’s territory uninvited. Edge is one big snake. Red’s gonna need a bigger plane…
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Haven’t read this yet
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You were finally getting your life back on track. Juggling college courses and a new job, you were slowly but surely rebuilding from the ground up, convinced the worst was behind you. That all changes when a magical summons you can't refuse rips you from your world and drops you into a house filled with powerful, skeletal monsters who despise you before you’ve even said a word.
To them, you are the arrogant and careless human who shattered the soul of their dearest friend, the gentle mage Lyra. They see you not as a person, but as a living tool—a magical "key" they require to heal the damage you supposedly caused. Trapped in a multiversal nexus with no way home, you must navigate a gauntlet of relentless animosity and suspicion.
Every word you say is twisted, every action is judged through the lens of lies you don't even know have been told. How can you survive in a home that isn't a home, surrounded by enemies who believe they are the heroes? And how can you prove your innocence when the true manipulator is the very person they've sworn to protect?
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11
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15
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You're an engineer who works for Ebott's best research facility in one of the labs; your lifelong dream after finding a journal on Mount Ebott when you were a kid. When you aren't in the lab being smart, you're gathering materials at the abandoned doll factory for the machine you're trying to build.
But one night, you meet a skeleton at the factory. Naturally, you lie about why you're there and say you're there to hunt ghosts. You befriend him and try to find a way to gather the materials while keeping up with that lie. But those lies catch up to you when you start to meet all the other skeletons.
Edit: As of Chapter 29, all chapters have been edited and fixed slightly!
- Language:
- English
- Words:
- 136,382
- Chapters:
- 52/?
- Comments:
- 1,018
- Kudos:
- 1,668
- Bookmarks:
- 359
- Hits:
- 47,357
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27
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Bookmark Notes:
52
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Summary
The Monsters emergence to the surface had changed the life’s of many.
There were some who had a hard time believing it wasn’t just a hoax, the only changes in their lives being the occasional glimpse of a Monster shopping at the local grocery store.
For others, the change was more severe.
Mimics. Humans whose soul reacted to the wave of magic that circled the world over when Monsters broke the barrier.
Their souls altered their bodies over night, mimicking the appearance of random Monsters. Their very DNA changed, leaving millions scared and confused.
She was one of them. Gathered up and put into the Omega Mimic Adoption Agency until a pack decided to ‘adopt’ her.
She can’t except this new life.
She won’t.
She’s still a human- right?
Or: soft and angsty recovery/found family/romance A/B/O skeleton poly fic where everyone is actually in the poly. Everyone is healing, 50 something years post emergence Swapfell, Horrortale, Underfell, Underswap and Undertale mashup, plus one very traumatized skele MC learning to live and not just survive.
Tooth rotting fluff and bumbling idiots trying to pspspspsps and offer their hand for our bbg to sniff like a cat will ensue
- Language:
- English
- Words:
- 81,218
- Chapters:
- 10/?
- Collections:
- 2
- Comments:
- 296
- Kudos:
- 675
- Bookmarks:
- 198
- Hits:
- 11,999
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Bookmark Notes:
10