Top 20 Long Crossover Fanfics
Ranked by AO3 kudos. Each fic is tagged with crossover and falls in the 50,000–100,000 words range.
Whispers in Corners
by esama
Everything started with a stumble - his new life in a new world as well as his surprisingly successful career as a medium.
My Soul, Your Heart
by Seriously_awkward_amy
Harry loses almost everyone he loves and discovers he is unable to follow them into the after life.He gets bored of moping in Grimmauld place so moves to the US, much to the thrill of MAUSA (who Harry firmly ignores). He settles in Forks, a quiet town that should give him the dull life he desires, t
Road to Nowhere
by Aerugonian
Hitoshi knows there's something wrong with himself before he's even old enough to have a sense of self. He looks at his reflection and knows that the infant looking back at him isn't what he should be seeing. His dreams are a maelstrom of grief and fear, his mind overwhelmed with a lifetime of emoti
There May Be Some Collateral Damage
by metisket
Ichigo’s been ordered to go undercover at a magic school to bodyguard a kid named Harry Potter, and this would be fine, except that he’s about as good at bodyguarding as he is at magic. And he considers it a good day, magic-wise, if he hasn’t set anything on fire.
Cathedrals
by KarasuYurei
After the events with Deucalion and Jennifer Blake, Derek goes on a search for his biological family. He, Stiles, and Cora head to New York City to try to find the family he doesn’t remember. It turns out that there was a lot to his adoption that he never knew.
An Irrevocable Condition
by Maeglin_Yedi
Harry doesn't age while everyone he loves does. Sick of losing all those around him, Harry decides to move to a new world thanks to a ritual Hermione found. He ends up in a shithole without indoor plumbing where he meets a small but clever fellow named Bilbo Baggins who brings him along on a little
Bye Bye Yesterday
by princessesandangels
After the assassination of Koro-sensei, Shiro survived to continue his experiments. And he kidnapped all of 3-E to be his first test subjects.His first Nomu.But something went wrong. Very wrong.And now, 27 terrified teenagers, one femme fatale and a terminally overworked government agent are waking
Be Careful What You Ask Your God
by Vexfulfolly
But Aki… And that is the thought. But Aki has always been different. But his future, when she touched the weft of fate, was delicate, as if one wrong move would have threads unraveling beneath her palms. A nudge, even a breath, might push him off course and send him wildly careening into a different
It’s gonna be the future soon, and I won’t always be this way
by Casimir
Something bad happens to Akabane Karma, something that wakes him up in a world completely unlike his own- and yet, here he is. Using the knowledge and skills Koro-sensei had given him and saving the world again.Vietnamese translation, by Minami093: https://my.w.tt/ZIrj12Ne2PCancelled after some issu
The Dragonborn Returns
by ChelleyPam
Six years ago Lord Stark’s bastard son vanished, caught up in a freak storm. Now the boy returns as a man, and he is much changed.
I Sang In My Chains Like The Sea
by orphan_account
In which Bilbo is a Jaeger pilot candidate, and Middle Earth stands on the brink of destruction.
Little Boy Blue and the Man in the Moon
by Ariana (ariana_paris)
Sherlock's unexpected visit to Princeton-Plainsboro, ostensibly on a case, threatens to turn House’s life upside down as he has to face up to a secret he has kept for thirty years.Author's note: This entire fic is based on the video “Cat's in the Cradle” by daasgrrl, which combines House (starring H
Beautiful, Wise, Powerful
by FergardStratoavis
Not all stories last a multitude of chapters. Sometimes, these little snippets persist through the ether, like fragments of a long-lost video now only seen in splotches.Heroes and villains, beasts and men - all will eventually answer Louise Françoise Le Blanc de La Vallière's heartful plea.
The White Wolf and The Woodland Prince
by bonchan
Legolas left Gondor after King Elessar’s coronation, hoping to avoid fading from a heart too bruised by unspoken longing. Unfortunately, fate had other plans, and he stumbled through a magical rift into Geralt of Rivia’s monster-infested morning."Well fuck! Another one!”“Thy tongue is foul, wanderer
Ars Goetia
by FoxOnPie
Byleth Eisner knew she was born a mercenary, she decided to live as a mercenary, and she assumed she would die a mercenary. The cards, however, told her that a different fate was in store for her, and meeting it would require the two skills she lacked in life: understanding people and understanding
MASTER OF DEATH
by mcsquared789
HARRY hated the deceptive idyll of Little Whinging — the oppressive sensation of being trapped somewhere he hated with people who wished he didn't exist, and an diminishing drivel of letters from his friends and family. Harry had witnessed death and horror, and yet he'd been left to rot here as if h
Rising Blade, Falling Leaves (Fate x Naruto, EMIYA Centric)
by TheTangerineCat
He woke up in Konoha. A clan that wasn't his. A name he'd never owned. But that hill of swords remained beyond even the transcendence of worlds. She scurried out of the alley. Blonde hair, blue eyes, whisker marks on dirty cheeks. Some weird kid was watching her. One brow up. Like she was a peculiar
Red Flags & Rift Rags
by RevasLavellan
Welcome to Pop Idol: Rift Closure Edition, AKA Fade-Out Tour: Thedas, the smash-hit spin-off that no one asked for. The Veil is torn, demons are pouring out of the sky, and the Inquisition is scrambling to hold the world together. Into this mess drops Mira, idol-turned-rift-closer, armed with nothin
Pax Elysia (Stargate x HP)
by Dragonspectre
Harry Potter has united the Hallows and gained access to Merlin's gift to wizardkind. But, a great purpose now falls on wizards and witches as they embark on a journey to the stars where many dangers and enemies lurks. Sequel to The Lion Cub.
Erid: Become Human
by radonadar
22 years after Ryland Grace chose Erid as his home, a massive ship arrived from Earth.There were no humans aboard. Only Connor and Chloe, two androids carrying a request from what remained of humanity.Now Grace must take on one more impossible mission for both humans and Eridians.But the androids’ a
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About Crossover
Two or more separate canons collide: characters from different universes meet, team up, fight, or fall in love. Crossovers range from elegant fusions that merge settings into one world to gleeful collisions that drop one cast into another's plot.
Crossovers answer fandom's eternal 'who would win' and 'would they get along' debates on the page, and the friction between universes generates stories neither canon could hold alone.
Common scenarios: Detectives from two different procedurals jurisdictionally forced onto the same case, or a fusion sorting one show's cast into another universe's institutions.
About This List
This list of 20long Crossover fanfics spans 1,392,241 total words. Kudos range from 86 on the newest entries to 29,909 on the most established. 40% are marked complete — check the status flag before committing to a longfic. The most common rating is Teen And Up Audiences (12 of 20 fics).
Recurring tags across this list: Crossover · Alternate Universe - Canon Divergence · Alternate Universe · Master of Death Harry Potter · Post-Traumatic Stress Disorder - PTSD.
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