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Undertale Yellow: Defiant Hope by Kanakoke_K9907
Fandoms: Undertale Yellow (Master Sword Video Game), Undertale (Video Game)
25 Sep 2025
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Summary
Snowdin, a place usually synonymous with joyous family outings and quality time, became the stage for a cruel twist of fate for young Kanako. She and her family, the Ketsukane, had ventured there for a day of simple pleasures, unaware of the darkness that had recently descended upon the snowy landscape. A human, clad in a dusty tutu, had arrived—not misunderstood or scared, but driven by a chilling love for the game, a thrill for chaos. In this alternate universe, their attacks were not born of fear, but of a cold, calculated desire to kill.
This human stumbled upon the Ketsukane family and, without hesitation, caught Chujin and Ceroba off guard, slaying them where they stood. All Kanako could do was watch in terror as her parents fell, their forms dissolving into dust. The memory, a searing brand, haunts her to this day.
Now many years into the future, she has grown and changed.
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A tragedy has struck the underground. Fear fill everyones souls as an unfamiliar disease begins to spread and numbers are slowly dwindling. Will they overcome this reign of terror or will they perish forever?
I think that this story has been going good. Thanks for all the support that I have received! And sorry for the horrible updates. I just post the chapters as I write them.
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After the neutral ending where papyrus becomes King, a new human falls into the underground after an earthquake hits.
This was originally on Wattpad.
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What happens when everything changes? Everything is the same but it isn't.
An entity from the stars descends to earth and disguised themselves as human. They witness history in this new era of monsters and humans, while also dealing with the demons that dare dirty the earth with their presence.
What happens when you step into the battleground from one universe, only to win and come out into another parallel world, except you’re the protagonist?
You weren’t one for the spotlight. You loved your sister, even if she wasn’t one by blood. You only wished for her well-being and happiness. Except here… she’s gone. And now you have to take her place and stand under the limelight as you walked your path in her place - the protagonist.
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I DON’T CONDONE MY WORKS TO BE TRANSLATED, REPOSTED AND/OR FED TO AI.
9/1/25 — thank you for 600+ hits!
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- Part 2 of Still As Stone AU
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The story of the human and monster war, now days just another bedtime story, but that is for the humans. Monsters live trapped underground, they have gone through famines, epidemics, lost of hopes and dreams, and all because the humans were scared of them. Hope came back when finally, a "human" fell down. But it just brought more misfortune.
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Flowey has discovered Susie exists in the undertale world, now everyone has to deal with the consequences.
(Part of a series, reccomended you read Second Chances up to chapter 5 before reading this)
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- Part 2 of Deltarune in Undertale AU
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One day a human falls down into the Underground. Unbeknownst to everybody however, they start hunting down every single monster in the Underground. Everyone is trying to do their best.
Let's explore their perspective.
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After a loop of running through the Underground countless times, something has changed. Presented with a timeline to finally grow up in, Frisk and Chara have had to learn how to navigate an ever changing world. But as time has passed, cracks have begun to show in the corners of their new lives. Everyone else is moving on, but it seems something from below the surface won't let them go.
Will they discover what's truly wrong with their world? How can they keep the peace in a world built on "kill or be killed"?
Will they ever truly let go?
Find out next time on UNDERTALE 2-
I mean whenever I decide to have motivation! -
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After years of war with the humans being mortally wounded, asgore and his monsters took refuge in the underground. Occasionally, humans would come down with intent to take revenge on the monsters, finish what was started, leading to the birth of Asgore's TRUE KNIGHTS. Those that capture and fuse with a human soul, the prime protectors of the underground. Determination is the only soul that can truly help them now.
Papyrus wanted nothing more to become like his brother, a protector, a guardian of those who cannot protect themselves, and he's finally got it, but at what cost?
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Why can't you stay with us? by clovernightstarz
Fandoms: Undertale (Video Game), Undertale Yellow
12 Jul 2025
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After Ceroba and Clover's fight in the suburbs of New Home, the former has a traumatic breakdown about letting another kid fall to their ideals much like her own daughter. This leads to Clover being kept alive at the end of the Pacifist route. However, the rest of the Underground hasn't given up on that SOUL they felt were promised to them. It seems that, with the little time Clover has left, perhaps they can help their friends in their own issues before they are caught.
// Heads up, this fanfic is HEAVILY INSPIRED by 'Don't bear the weight of the world alone' by SkyWatcher3, and leans into the 'ceroba-adoption' headcanon quite a bit. If you enjoy this fanfic, i heavily recommend giving the one mentioned above a read.
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(Y\N) is a young female spy and soldier fighting in the War of Humans and Monsters. She is fighting on the humans' side of the war until a turn of events when she becomes apprehended by the enemy. What will happen when a young monster scientist tries to change her views?
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The forests of Underfell are expansive. When the Fell brothers investigate in one of the worst blizzards of the Underground, they find something unexpected.
Series
- Part 1 of A Rogue What?!
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It's been 10 years since Mettaton took over the Underground. Anne, a 15 year old girl, falls down after trying to check if a message she hears in an old phone she finds is real. Anne arrives at the Underground, oblivious to the dangers in the kingdom, except for bits of information from the message. Throughout her journey, Anne discovers the truth about the Underground with the help of other monsters and she also discovers some things about herself.
Royal Bullet's plot extends parts of Undertale's canon plot, and contains some headcanons of mine.
Special thanks to my beta reader, thelegendofmudkip: https://thelegendofmudkip.tumblr.com/
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You managed to escape being trapped underground after running into the forest when your parents died in the war. You were up on the surface from birth up until you were the human equivalent of 18. On your 1800th birthday, you escaped your abusive foster home to join the rest of your kind below Mt. Ebott.
I update very irregularly, I try my best but don’t expect updates every week. I tend to evaporate off the face of the Earth sometimes. It’s either that or you get 3 chapters in one day. Have fun reading!
(I hate slow burns, but this won’t be quick. There will be children and unusual anatomy because skeletons) -
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You’ve never been more afraid than you are now.
Series
- Part 3 of Literary Reserve
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Four years after Frisk the Human descended into the cavern of Mt. Ebott, their older sister, Lone, comes to find them.
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While taking a walk with your cat, trickles of rain turn into a heavy downpour, forcing you to take shelter in a cave. You lose your cat in the darkness, and in a desperate attempt to find her, you slip and fall into the depths of the Underground. Can you and your cat survive the harsh elements, as well as the monsters of a lost race? Perhaps... things aren't so bad down here.
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hi
umhad an idea to make a fun little series where frisk is a cat
was going to be just frisk at first but on a whim I just added reader as well as made the plotline a bit darker
this is my first official work on ao3, but I have ideas for other works if this idea falls through or I just get bored of it
anyways feel free to leave tips or anything in the comments if u somehow find this series
enjoy <3
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"Fuck, Sans... If you had killed this human the day you found her, we wouldn't be here..." Undyne whispered to him, filled with remorse and guilt.
She passed his hands behind his back, anti-magic handcuffs surrounding them. Checking their placing, she locked them.
Sans could not tell if she was hating him. Perhaps she was blaming herself, too. Perhaps everyone was feeling a little responsible. At least, he hoped so."Why did you do that?" she sighed, rhetorically.
"I did it out of love." Sans simply replied.
"That’s the stupidest excuse you could have chosen..."
•| ⊱❦⊰ |•
Corrupted by the Lust, monsters live a hell everyday, sex and immorality being a daily routine.
Sans is one of the most luxurious of them and then, the one who had always been the most disgusted by all of that. He lost hope. He lost will.One day, while going to this giant purple door, he found a package. A human baby. And strangely, Sans felt... at peace.
Now, Sans has something to protect from this world. And he is not going to give up, even when everyone seems to be against him. But it might be easier than he thought: it seems that this little girl can change hearts...
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Deltatraveler Pure Mode by gen3king
Fandoms: Undertale (Video Game), Deltarune (Video Game), Mother 2: Gyiyg no Gyakushuu | EarthBound, Undertale
24 Sep 2024
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After a near death experience, traumatized 13 year old Richard West awakens, rescued by W.D. Gaster, who offers him a chance to revive his dead infant sister for assisting in his research. Richard agrees, making new allies along the way including Clover and Flowey. However Richard is not... mentally sound, suffering from D.I.D. and severe anxiety and depression. Unlike the original Deltatravelers his journey is more desperate and floundering, requiring him to seek different allies and pathways through each world on his quest to revive his sister, as his past that made him this way slowly comes to light. Worse still, this is not his first brush with violence, and old habits die hard...
Think of this as a hard(er) mode for Deltatraveler with a more character-driven plot and a less meta plot.
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It's been 6 years after monsters surfaced they have taken over everything. Humans have been hunted down to nothing due to the monsters outcry for revenge. A college girl gets captured and is sold to a skeleton monster to now solve the lack of humans to hunt. Will Seven be able to break free from the monsters of her world and get shown some safety in the next world.