Undertale Crossovers
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Sonic in Undertale by Archaeopteryx108 reviews
(This is a work in progress. I own nothing. Sonic is owned by SEGA, and Undertale is a product of Toby Fox.) When a blue hedgehog that can go faster than the speed of sound and a small child fall into a mountain… they will find something quite unexpected… This is a version of the Pacifist Route with Sonic in it. I will upload infrequently. Review if you enjoy!
Crossover - Sonic the Hedgehog & Undertale - Rated: K+ - English - Adventure/Friendship - Chapters: 5 - Words: 5,450 - Reviews: 3 - Favs: 9 - Follows: 11 - Updated: 8/30 - Published: 6/17/2022 - Sonic, Frisk, Chara
Worlds above the Underground (Rewrite) by bopdog111 reviews
(Rewrite of Ulrich's idea) Frisk Dreemurr did the impossible and freed the monsters from their prison under Mt. Ebott. She saved all of monster kind and even went the extra mile to try and bring back Chara and Asriel and succeeded. Now on the Surface the three Dreemurr children have a new goal, becoming three great Entertainment Duelists. Co-Write with Ulrich362
Crossover - Yu-Gi-Oh! Arc-V & Undertale - Rated: T - English - Suspense/Adventure - Chapters: 24 - Words: 143,768 - Reviews: 6 - Favs: 34 - Follows: 36 - Updated: 8/29 - Published: 2/8/2021 - [Yuya S., Frisk] [Yuzu H., Asriel]
Undertale: Memento Mori, Unus Annus! by bopdog111 reviews
In the aftermath of Frisk breaking the barrier of Mt. Ebott, and becoming the Ambassador of Monsters, he has a new goal in life; to one day make up with his brother Ken, and not let him down. Arriving back at Tatsumi Port Island later, Frisk, and his friends alongside Asriel, and Chara both back to normal find the Shadows, and join S.E.E.S to stop them. MaleFrisk FemaleChara
Crossover - Persona Series & Undertale - Rated: T - English - Supernatural/Adventure - Chapters: 3 - Words: 25,421 - Reviews: 1 - Favs: 12 - Follows: 10 - Updated: 8/27 - Published: 8/3 - Mitsuru K., Minako A./Hamuko Y., Frisk, Chara
In All The Wrong Places by Zetic reviews
Long after the Human-Monster war, the surface fell into a state of total chaos and became an unending nightmare. The eighth human, someone broken and reshaped by that nightmare, is about to enter the Underground, and is bringing far more than a simple stick or dull kitchen knife... Soulsborne Series crossover AU, OC Undead protagonist.
Crossover - Dark Souls & Undertale - Rated: M - English - Adventure/Romance - Chapters: 37 - Words: 192,699 - Reviews: 235 - Favs: 630 - Follows: 663 - Updated: 8/21 - Published: 10/27/2015 - [Wanderer, Toriel] Asriel
Hero of the nights tide Undyne! by Howeverhell
This is a MHA X Undertale story. 20 years before the canon of my hero acidemia a girl is born with deep blue skin, shining scales, glowing yellow eyes, teeth sharp as razors and claws to match. due to no fault of her own this girl is given up for adoption mere days after her birth. and this is the story of that young girl and how she became a true hero
Crossover - My Hero Academia/僕のヒーローアカデミア & Undertale - Rated: T - English - Adventure/Humor - Chapters: 1 - Words: 8 - Favs: 5 - Follows: 10 - Published: 8/20
Fallen Spider by Cap10FroggerGuy reviews
When Peter Parker wakes up in some strange cavern after a long fall, he quickly finds the world he is in is full of monsters: Most friendly, but a few wanting him dead. Along with a snarky disembodied voice, he travels this world to find his way home... hopefully in one piece. NOTE: Spoilers for Undertale and FFH. I have also made Chara specifically female for simplicity's sake.
Crossover - Avengers & Undertale - Rated: T - English - Adventure/Friendship - Chapters: 37 - Words: 65,404 - Reviews: 64 - Favs: 114 - Follows: 101 - Updated: 8/13 - Published: 5/22/2020 - Complete
The Duelist of Mt Ebott (Remastered) by bopdog111 reviews
Remake of my first SOUL Monsters installment! 2 years after releasing Mt. Ebott from the barrier, Frisk wins a contest hosted by Kaiba Corp. to gain tuition at Duel Academy. What awaits her are new friends, new rivals, and perhaps even some love while dealing with two shadowy groups known as the Shadow Riders, and Gastly Shadows for the Sacred Beasts. FemFrisk. FriskxChazz
Crossover - Yu-Gi-Oh GX & Undertale - Rated: T - English - Supernatural/Adventure - Chapters: 17 - Words: 106,217 - Reviews: 5 - Favs: 25 - Follows: 25 - Updated: 8/8 - Published: 7/20/2023 - [Chazz P./Manjōme J., Frisk] Jaden Y./Jūdai Y., Undyne
Redemption is a world away by W.D. Helvectic
Finding himself in a new body after committing suicide, Akaza sees the struggle of survival through the memories of his new body. He never thought he could redeem himself, but the opportunity seemed to be a gift from the very gods that had forsaken him long ago. Hopefully, this time around he can be worthy to join Koyuki in the after-life.
Crossover - Undertale & Demon Slayer: Kimetsu No Yaiba - Rated: T - English - Hurt/Comfort/Humor - Chapters: 2 - Words: 5,208 - Favs: 5 - Follows: 6 - Updated: 7/20 - Published: 4/10 - Papyrus, Sans
Forsaken Light by La fille du Temps reviews
After a nearly infinitly RESET genocide run, StoryShift!Chara wake up at the surface, changed from her memories and mostly unknown. Under the surveillance of the heroes, she'll wander in the heroe's lands with a new emotion filling her SOUL. (StoryShift!Chara. SS!Chara. Fem!Chara. Potential yuri.) (Rated M for future darker moment and atmosphere)
Crossover - My Hero Academia/僕のヒーローアカデミア & Undertale - Rated: M - English - Chapters: 1 - Words: 1,455 - Reviews: 5 - Favs: 12 - Follows: 22 - Published: 7/16 - Toshinori Y./All Might, Shouta A./Eraserhead, 1-A Students, Chara
Re:Darkness by Alejandro Montero reviews
A young man is being ripped out of his universe just like how Natsuki Subaru was supposed to, but in it's way through the void Satella's magic lost grasp of him, the void started consuming him but before he was kill, something changed.
Crossover - Undertale & Re:Zero - Rated: M - English - Romance/Adventure - Chapters: 1 - Words: 1,391 - Reviews: 2 - Favs: 1 - Follows: 1 - Published: 7/16 - OC, Gaster, Emilia, Rem
The Destination Follows the Journey by Shippo704
They just wanted to be themselves. Their parents didn't listen. They didn't understand. When their parents wanted to send them to a conversion camp, they decided it was time to run away. After an incident in the nearest national park, they find themselves in world of monsters and magic. Then, along their journey, they make friends and find themselves too.
Crossover - Undertale & Wayward Children series - Rated: T - English - Adventure/Hurt/Comfort - Chapters: 36 - Words: 162,405 - Favs: 7 - Follows: 3 - Updated: 7/15 - Published: 10/5/2022 - Frisk, Sans, Toriel, Mettaton
Undertale multiverse meets with my hero academia by wolffrankie.14 reviews
What would happen if the Undertale multiverse collided with the My Hero Academia multiverse? First off, I may not continue the story. I'm just trying to practice, so don't expect any more. But if people like the idea, I can try.
Crossover - Undertale & My Hero Academia/僕のヒーローアカデミア - Rated: T - English - Mystery/Drama - Chapters: 1 - Words: 250 - Reviews: 3 - Favs: 2 - Follows: 4 - Published: 7/6 - Sans, All For One, Izuku M., Toshinori Y./All Might - Complete
Hiccup the flower by TheFuriousNightFury reviews
What would happen if Flowey came to the HTTYD world? (This story needs serious work)
Crossover - How to Train Your Dragon & Undertale - Rated: K - English - Chapters: 5 - Words: 5,990 - Reviews: 7 - Favs: 13 - Follows: 14 - Updated: 7/2 - Published: 12/22/2016 - Hiccup, Flowey
An Underground Trip by BirdWatcher2 reviews
This is a story of Percy Jackson falling into the world of Undertale sometime after the Heroes of Olympus series. He goes through the journey of the game you know, but with some twists along the way. When Sans comes face-to-face with Percy Jackson and sees his insanely high level, how will he react? And what will Percy decide? Find out if you wish.
Crossover - Percy Jackson and the Olympians & Undertale - Rated: K+ - English - Angst/Humor - Chapters: 14 - Words: 24,031 - Reviews: 5 - Favs: 38 - Follows: 40 - Updated: 6/30 - Published: 8/6/2022 - Percy J., Sans, Toriel - Complete
The Memoir of Frisk by dafid1 reviews
What if Frisk went to the world of Fairy Tail?
Crossover - Fairy Tail & Undertale - Rated: K+ - English - Adventure/Friendship - Chapters: 11 - Words: 14,473 - Reviews: 19 - Favs: 59 - Follows: 58 - Updated: 6/26 - Published: 6/5/2022
Strykertale by Charisonic558 reviews
This small spinoff story of "Journey of a Saiyan" follows Stryker; a human with the ability to manipulate ki who manages to find himself in the underground and is on a quest to escape and free everyone. He'll need all the determination he has to make it through without the help of Cherik at his side.
Crossover - Dragon Ball Z & Undertale - Rated: T - English - Adventure/Friendship - Chapters: 9 - Words: 30,465 - Reviews: 2 - Favs: 5 - Follows: 8 - Updated: 6/26 - Published: 5/27/2017 - Complete
When a Rose has to choose between two Thorne's by annie4life
When Rose Bakugo comes home for a vacation she has a choice to make , will she be able to make the right choice I don't own my hero or Undertale I just own Rose my oc Full credit for the summer goes to my friend Dillon editing is done by him and one other friend of mine.
Crossover - My Hero Academia/僕のヒーローアカデミア & Undertale - Rated: T - English - Adventure/Romance - Chapters: 4 - Words: 4,009 - Favs: 1 - Follows: 1 - Published: 6/21 - Katsuki B., 1-A Students, OC, Sans
To Remember by Maazen reviews
He just wanted to leave it all behind and when he thought that his death gave him exactly that, a reprieve from the family he hated, he woke up again. Well, if they cant reach him and only memories remain, then maybe, just maybe he can start over. Maybe he can live a life free of solitude and hatred. Yes, that sounds nice. Gamer/OC Harem
Crossover - High School DxD/ハイスクールD×D & Undertale - Rated: M - English - Adventure/Supernatural - Chapters: 6 - Words: 60,011 - Reviews: 40 - Favs: 161 - Follows: 219 - Updated: 6/18 - Published: 5/27
Sum Of Parts by RpgNot reviews
They had just died, he had just woken up in his own mind and they were just created an hour ago. Now, after some messing around by a higher power, all three end up in the same body with a system that entered lockdown mode after having its connection with the host severed. Now, they have to figure out how to get their own bodies while also having to put in effort for once.
Crossover - High School DxD/ハイスクールD×D & Undertale - Rated: T - English - Adventure/Angst - Chapters: 1 - Words: 10,439 - Reviews: 1 - Favs: 7 - Follows: 7 - Published: 6/18 - OC, Papyrus, Sans
Stupid Dance Forbidden by Yoshizilla-Rhedosaurus
Meloetta gets hungry and wants to have a bunch of spider cookies from Muffet who challenges her to a match.
Crossover - Pokémon & Undertale - Rated: T - English - Fantasy/Humor - Chapters: 1 - Words: 531 - Published: 5/20 - Meloetta, Muffet
His Timeline by Alenshi
Kai Smith. In the Underground. Surrounded by monsters unlike anything he's ever seen before. All sorts of shenanigans ensue. This should be pretty self-explanatory, let's be real here.
Crossover - Ninjago & Undertale - Rated: M - English - Adventure/Drama - Chapters: 3 - Words: 4,460 - Favs: 1 - Follows: 1 - Updated: 5/1 - Published: 5/21/2022 - Kai, Sans, Toriel, Flowey
WindWalker Determination by TwilightDawnRider reviews
Compa and Iffy were discovering a new mountain called mount Ebbot but they wind up falling into the cavern where the monsters reside. Would they have to fight to get free, or are these monsters not like the ones in Gamindustri? Will the folks in Gamindustri try to save them? Is there a dark secret in these Caverns? Will the two girls know what to do when the time comes?
Crossover - Hyperdimension Neptunia & Undertale - Rated: T - English - Humor/Friendship - Chapters: 14 - Words: 50,868 - Reviews: 1 - Favs: 13 - Follows: 18 - Updated: 4/30 - Published: 12/4/2022 - Compa, IF, Frisk, Sans
Kingdom Hearts Lost Keywielder: Undertale Arc by Bigtex91 reviews
Welcome to the world of Mt. Ebott, a world populated by humans on the Surface, and Monsters in the Underground that were sealed away many years ago by the Humans. Our keyblade wielding adventurers Rick and Chloe find this world the first of many on their adventures, what sort of dangers await them? What sort of friends will they meet? Come along and find out.
Crossover - Kingdom Hearts & Undertale - Rated: T - English - Adventure/Humor - Chapters: 10 - Words: 31,921 - Reviews: 1 - Favs: 4 - Follows: 4 - Updated: 4/27 - Published: 8/9/2021 - OC
Unamed Mha x Undertale Fanfiction by NoImNotTellingMyActualUsername
Izuku falls into the underground...
Crossover - My Hero Academia/僕のヒーローアカデミア & Undertale - Rated: M - English - Angst - Chapters: 2 - Words: 315 - Favs: 2 - Follows: 2 - Published: 4/16 - Izuku M., Chara
Izuku: Hero of Monsters by Evarstar101 reviews
On the day Izuku would have received One For All, another path was taken. After the boy failed to save Bakugou and was berated by the heroes, Izuku left for Mount Ebott on the edge of Mustafu. Taking Bakugou's advice he plummets into the mountains in hopes of a quick end. Unknowing he was in for an adventure of long forgotten history and lost magic.
Crossover - My Hero Academia/僕のヒーローアカデミア & Undertale - Rated: T - English - Fantasy/Adventure - Chapters: 2 - Words: 7,314 - Reviews: 14 - Favs: 48 - Follows: 61 - Updated: 4/15 - Published: 4/10 - Izuku M., Toshinori Y./All Might, Katsuki B., Chara
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