Undertale Crossovers
Filters
1.7K | Page 1 2 3 4 11 .. Last Next »

A New Home by SmaugvsDragonBorn reviews
Fem!Harry is abandoned by her relatives at the summit of Mt. Ebbot. These are her adventures. This story is not beta-read. Please leave reviews and constructive criticism.
Crossover - Harry Potter & Undertale - Rated: K - English - Chapters: 8 - Words: 7,215 - Reviews: 5 - Favs: 11 - Follows: 14 - Updated: 10/6 - Published: 9/7 - Harry P., Voldemort, Frisk, Chara
We're Screwed by boredgrace23 reviews
Asgore finds an old, incomplete painting he did of a man playing the piano.
Crossover - Undertale & Deltarune - Rated: T - English - Angst/Romance - Chapters: 5 - Words: 24,394 - Reviews: 3 - Updated: 10/5 - Published: 7/10 - Asgore D., Gerson, Gaster, Kris Dreemurr
DemigodTale by AnnabethChase101 reviews
Waking up on a strange mountain with no memory would have been enough for Percy. Falling down a giant hole and meeting strange monsters that don't know about demigods? Even worse. Now he has a new quest: make it out. Join Percy as he encounters strange friends and deadly enemies, all while questioning if he really is the hero. Takes place in the months before the Son of Neptune.
Crossover - Percy Jackson and the Olympians & Undertale - Rated: T - English - Adventure/Friendship - Chapters: 4 - Words: 12,300 - Reviews: 2 - Favs: 4 - Follows: 4 - Updated: 10/3 - Published: 9/29 - Percy J., Sans, Asgore D., Flowey
A life-long story by bonan4398 reviews
A simple question arose one day. What happens if some fandoms and their events take place in the same universe, on the same planet and in the same world, while somehow intersecting with each other? Now with this answer I want to share with you. It all started with a kind fairy tale, telling about friendship and kindness, and a family where there is a child who owns a power...
Crossover - Five Nights at Freddy´s & Undertale - Rated: T - English - Friendship/Family - Chapters: 27 - Words: 69,649 - Reviews: 2 - Favs: 4 - Follows: 4 - Updated: 10/2 - Published: 7/6 - The Murderer/William Afton, Big Brother, The One You Should Not Have Killed, Elizabeth Afton
Unmei Force Shattered Heroes: Dawn of Despair by Xovercreator reviews
The X-Event finally makes their moves, as the member of the Unmei Force, as well as those of the Future Seekers, seek to pursue the X-Event, so that they can find X-Gaster, and put an end to his genocidal plans once and for all. However, it seems that their quest will not be without its own problems, and it's only a matter of time until Richard awakens...
Crossover - X-overs & Undertale - Rated: T - English - Chapters: 6 - Words: 78,560 - Reviews: 1 - Favs: 1 - Follows: 2 - Published: 10/2 - Complete
When She Loved Me by Dragonsrule18 reviews
Every story has a beginning, and Frisk and Ralsei's childhood friendship is no exception. A collection of oneshots of Frisk and Ralsei's lives together, from when they met at five until they were separated at seven. Set as a prequel to the Hopes, Dreams, And DELTARUNE universe.
Crossover - Undertale & Deltarune - Rated: T - English - Friendship/Hurt/Comfort - Chapters: 2 - Words: 4,638 - Reviews: 1 - Favs: 2 - Follows: 2 - Published: 9/30 - Frisk, Ralsei
Unwavering Will in the Sea by dafid1 reviews
What if Frisk from Undertale went to the world of One Piece? See what happens as Frisk goes on a new adventure!
Crossover - One Piece & Undertale - Rated: K+ - English - Adventure/Friendship - Chapters: 77 - Words: 123,308 - Reviews: 73 - Favs: 253 - Follows: 250 - Updated: 9/28 - Published: 11/28/2020 - Luffy, Frisk
The Mountain of two Legends! by bopdog111 reviews
Frisk succeeded in freeing the Underground from the Barrier, and all is freed back to Tamriel... too much they see is wrecked with strife from the Thalmor, and now a Dragon Menace. Teamed up with Jin, a former Soldier of the Imperial Empire, and the fated Dragonborn, they all travel to stop the Dragon Meance, and the Thalmor in a unlikely alliance. (Pairings Undecided)
Crossover - Elder Scroll series & Undertale - Rated: T - English - Family/Adventure - Chapters: 11 - Words: 59,433 - Reviews: 2 - Favs: 14 - Follows: 13 - Updated: 9/25 - Published: 6/30/2022 - Dragonborn/Dovahkiin, Delphine, Frisk, Chara
Skeletal Shenanigans by Possession Unknown reviews
Once the monsters and Frisk left the Underground, after the events of the pacifist route they find themselves in Japan next to the small town of Kouh. The group decided they wanted to set up residence in Kouh, Now all they needed to do was greet the locals, Frisk being their ambassador... Turns out they seemed a bit monstrous themselves, well at least some of them.
Crossover - High School DxD/ハイスクールD×D & Undertale - Rated: M - English - Supernatural/Friendship - Chapters: 1 - Words: 2,325 - Reviews: 1 - Favs: 5 - Follows: 8 - Published: 9/23 - Rias G., Frisk, Sans, Papyrus
Frisk Dreemurr and the Sorcerer's Stone by sparrow0sborne reviews
Frisk Dreemurr is an ordinary eleven year old girl, aside from the fact she freed all monster kind from the underground almost two years ago. But shortly after her eleventh birthday, she discovers something shocking. She's a magical witch and she's been accepted into Hogwarts School of Witchcraft and Wizardry!
Crossover - Harry Potter & Undertale - Rated: K+ - English - Fantasy/Adventure - Chapters: 1 - Words: 1,331 - Reviews: 2 - Favs: 3 - Follows: 6 - Published: 9/22
MoniTale by Joker the prince of all crime reviews
"This was never meant to happen, you should have just brought them back." Player said as he went to delete her , but then something caught his eye. The Monika lover smiled as he looked at the Heart. "Maybe you can still learn." He moved her file over to UNDERTALE and opened it's files. He was finding a spot to put her, hovering over Frisk's. Then the lightning struck them..
Crossover - Undertale & Doki Doki Literature Club - Rated: T - English - Adventure/Hurt/Comfort - Chapters: 26 - Words: 115,003 - Reviews: 164 - Favs: 226 - Follows: 280 - Updated: 9/22 - Published: 2/21/2018
SOULS of Barian! by bopdog111 reviews
Sequel of "The Hope Reborn". Years after Illaster's defeat the Princeton Family seem to do unfinished business with the Anomaly, and Agate who escaped, and are facing a new threat from the Barians, and the Number cards with allies from Astral World, and Yuma Tsukumo. Co-Written with Ulrich362. SharkxOC, RioxOC, YumaxCathy
Crossover - Yu-Gi-Oh! ZEXAL & Undertale - Rated: T - English - Romance/Adventure - Chapters: 30 - Words: 208,349 - Reviews: 4 - Favs: 26 - Follows: 19 - Updated: 9/19 - Published: 9/11/2020 - Ryoga K./Shark, Rio K., OC, Frisk
Antebellum by Novice Lowland reviews
After the events of Undertale, peace has been brought to the above ground and a new nation is formed. However, a Ebott science project goes wrong, Frisk going missing in the process and ending up in a strange new world. Sans going in to save them, what comes next is filled with slice of life fun and jaw dropping action. [Updates every Sunday]
Crossover - Touhou Project & Undertale - Rated: T - English - Adventure/Mystery - Chapters: 7 - Words: 25,945 - Reviews: 2 - Favs: 5 - Follows: 6 - Updated: 9/17 - Published: 7/3
Chocolate and Cinnamon by Scrappymocha reviews
What if Izuku had a dog called Mighty and didn't save bakugo? What if Chara wasn't some psychopathic demon and got teleported into Izuku's room? Well that happens in this fic. Looking for a better name lol.
Crossover - My Hero Academia/僕のヒーローアカデミア & Undertale - Rated: M - English - Chapters: 2 - Words: 2,541 - Reviews: 19 - Favs: 22 - Follows: 36 - Updated: 9/15 - Published: 8/26 - [Izuku M., Chara]
Paranormal Academia (Version réécrite) by MonstaLia reviews
La vie de Léa change du tout au tout quand des monstres surgissent de nulle part pour l'attaquer et qu'elle se retrouve contrainte de vivre dans une académie loin des humains.
Crossover - Slender & Undertale - Rated: M - French - Adventure/Horror - Chapters: 40 - Words: 138,732 - Reviews: 1 - Updated: 9/15 - Published: 2/7/2020 - 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: 7 - Words: 45,861 - Reviews: 1 - Favs: 8 - Follows: 8 - Updated: 9/14 - Published: 7/20 - [Chazz P./Manjōme J., Frisk] Jaden Y./Jūdai Y., Undyne
Sierra by bayramlit7
Legendary Celeste Mountain. Mythical Mount Ebott. The tales of these two ancient places are over. But what about those who came out victorious from their depths? Their stories were far from over. Thanks to a twist of fate, Madeline embarks on an unexpected adventure that shatters the boundaries of her world and intersects with the path of the young ambassador of monsterkind.
Crossover - Undertale & Celeste - Rated: K - English - Friendship/Supernatural - Chapters: 1 - Words: 1,363 - Favs: 2 - Follows: 2 - Published: 9/10
Into a New Reality by attripae reviews
After fighting in Chara's genocide run for what seemed like a lifetime now, Sans devised a new plan to get rid of the wraith, in the hopes of giving his brother a happier life. In doing so, there were unintentional side effects and Sans found himself in an entirely new world. Undertale—more specifically, Sans, meet the Marvel Cinematic Universe.
Crossover - Marvel & Undertale - Rated: K+ - English - Sci-Fi/Fantasy - Chapters: 37 - Words: 79,942 - Reviews: 9 - Favs: 62 - Follows: 80 - Updated: 9/8 - Published: 2/7 - Sans
Maelstromtale by hussbek reviews
Stories speak of a mountain where children have gone and never returned, unknown of the mystery which lies within it. Now history repeats itself as a child falls but with a twist as another joins...and to think a mild stroll got him into something thought of as fairy tales.
Crossover - Naruto & Undertale - Rated: T - English - Adventure/Supernatural - Chapters: 24 - Words: 184,498 - Reviews: 222 - Favs: 411 - Follows: 462 - Updated: 9/7 - Published: 5/25/2020 - Naruto U., Frisk
A Rabbit In The Underground by SbOcean reviews
The Underground had seen an incalculable number of resets. Frisk, Sans and Flowey are tired of each reset, but in one reset, two new people fall into the Underground. Will these two break the cycle or will they become a part of it? Spoilers for Undertale and Fnaf Security Breach
Crossover - Five Nights at Freddy´s & Undertale - Rated: T - English - Horror/Family - Chapters: 25 - Words: 35,560 - Reviews: 25 - Favs: 38 - Follows: 47 - Updated: 9/5 - Published: 5/19/2022 - Vanny/Reluctant Follower, Gregory, Frisk, Sans
Ghost of a Chance by Cypher0 reviews
It was never meant to end this way. The six SOULs should have just drifted off into the abyss after that abomination of a garden plant was defeated. But that stubborn, reckless, idiotic kid decided to stick his nose into things he didn't understand.
Crossover - Undertale & Doki Doki Literature Club - Rated: T - English - Supernatural/Suspense - Chapters: 1 - Words: 481 - Reviews: 1 - Favs: 1 - Follows: 1 - Published: 9/4 - Orange Soul, MC
A Monsoon Of Determenation by darkshadowmaverick
one night Monsoon who's married to sailor Pluto has a nightmare in which the aftermath requires the intervention of both Jack/Raiden & JetStream Sam and thats not even the half of it all...
Crossover - Metal Gear & Undertale - Rated: M - English - Drama/Tragedy - Chapters: 1 - Words: 1,600 - Published: 9/1 - Monsoon, Frisk, Chara
The Surface by Polarfog
Monsters are freed from Mt. Ebott by a military group. Many monsters are already free, as Mt. Ebott monsters were freed last for being known as the most dangerous monsters. Can they adjust to a society critical of their merciless killings?
Crossover - Undertale & OMORI - Rated: T - English - Chapters: 8 - Words: 8,593 - Favs: 1 - Follows: 1 - Published: 8/30 - Frisk, Sans - Complete
Meeting of the Worlds: Beneath the Multiverse by DouglasJack reviews
In a twist of fate, Ben Tennyson, the intergalactic hero, is transported from his cosmic battles to an unfamiliar underground w what will he do without friends and allies? Will he be able to stop his old enemies as they unite to defeat him? (only M rating because i thought about adding blood and profanity)
Crossover - Ben 10 & Undertale - Rated: M - English - Adventure - Chapters: 4 - Words: 23,279 - Reviews: 15 - Favs: 9 - Follows: 8 - Updated: 8/27 - Published: 8/18
Under the Veil by poplasia reviews
Sans has gotten himself stuck in the void between worlds in a successful attempt to stop the resets of his timeline. He's not sure how long he's been chillin' alone there, but eventually a chance at escape stumbles his way in from the Veil of Death. His name?—Sirius Black. (no pairings)
Crossover - Harry Potter & Undertale - Rated: T - English - Fantasy/Humor - Chapters: 69 - Words: 244,703 - Reviews: 2222 - Favs: 2,400 - Follows: 2,709 - Updated: 8/26 - Published: 8/1/2016 - Sirius B., Sans
1.7K | Page 1 2 3 4 11 .. Last Next »