Alternate Universe (AU) Tags on AO3
Every way fandom relocates beloved characters — the full family of AU tags, from canon divergence to total reinvention.
'AU' is one of the broadest words in fandom, covering everything from a small change in canon to a complete reinvention of the world. The Alternate Universe family of tags is how authors signal which kind of departure you're getting before you commit.
This guide gathers the AU tags in one place so you can see the range: Canon Divergence keeps the world but changes events; setting AUs (coffee shop, royalty, mafia) transplant the characters somewhere new; fusion AUs borrow another story's universe entirely. Each is its own door into the fandom.
The 110 tags in this group
Alternate Universe
The umbrella tag for any fic that changes the fundamental premise of canon, whether that means relocating characters to a coffee shop or rewriting the rules of their world entirely.
Alternate Universe - 1920s
Pours the cast into the Jazz Age: speakeasies, flappers, bootleggers, and glittering parties with something desperate underneath.
Alternate Universe - 1940s
Sets the story amid wartime and its aftermath — ration books, swing dances, factory floors, and letters that take months to arrive.
Alternate Universe - 1950s
Stages the cast in the decade of diners, drive-ins, and aggressively enforced normalcy.
Alternate Universe - 1980s
Rewinds to mixtapes, mall food courts, arcade cabinets, and synth on every radio.
Alternate Universe - 1990s
The last analog decade as a setting: video stores, dial-up screech, burned CDs, and hanging out because no one could text instead.
Alternate Universe - Actors
Casts the characters as performers — film stars, theater troupe members, soap regulars — often playing love interests on screen while figuring out whether the chemistry is scripted.
Alternate Universe - Aliens
Introduces extraterrestrials into the premise — characters reimagined as aliens, first-contact scenarios, or abduction setups played for horror, comedy, or romance.
Alternate Universe - Alpha/Beta/Omega Dynamics
The A/B/O or Omegaverse tag, marking a universe where humans have a secondary sex — alpha, beta, or omega — complete with heats, ruts, scenting, and biological pair-bonding.
Alternate Universe - Angels & Demons
Recasts characters as celestial and infernal beings — guardian angels falling for their charges, demons going soft, Heaven and Hell as rival bureaucracies.
Alternate Universe - Apocalypse
Covers the world actually ending in real time — meteor inbound, plague spreading, sky cracking open — rather than the aftermath.
Alternate Universe - Arranged Marriage
Marries the main pairing by contract, treaty, or family decree before they've chosen each other — royal alliances, business mergers, omegaverse arrangements, or cultural tradition.
Alternate Universe - Assassins & Hitmen
Arms the characters and gives them contracts: rival killers assigned the same target, an assassin who can't pull the trigger on this one mark, retirement plans interrupted by one last job.
Alternate Universe - Bakery
Puts characters behind the pastry counter or in front of it, trading canon conflict for flour-dusted domesticity.
Alternate Universe - Ballet
Stages the cast in the unforgiving world of classical dance — company hierarchies, casting wars, bleeding feet, and the pursuit of an impossible standard.
Alternate Universe - Band
Forms the characters into a musical act — garage hopefuls, touring veterans, or something in between — and mines the inherent intimacy of making music together.
Alternate Universe - BDSM
Constructs a universe where BDSM is societally structured — most commonly a world in which everyone has a dominant or submissive orientation recognized by law and custom.
Alternate Universe - Boarding School
Encloses teenage versions of the cast in a residential school — uniforms, house points, midnight kitchen raids, and nowhere to escape the person you're feuding with.
Alternate Universe - Bodyguard
Assigns one character to protect the other — pop star and security detail, royal and sworn shield, witness and handler.
Alternate Universe - Bookstore
The bibliophile's small-business AU, starring a cluttered independent bookshop, a clerk with strong opinions about shelving, and customers who linger too long in the stacks.
Alternate Universe - Canon Divergence
One of the most-used tags on the entire Archive, marking stories that follow canon faithfully until a single chosen moment and then branch off.
Alternate Universe - Celebrity
Makes at least one character famous — musician, actor, athlete, influencer — and builds the story around fame's distortions: privacy lost, relationships conducted through publicists, and the question of who loves the person versus the brand.
Alternate Universe - Childhood Friends
Rewrites history so the characters grew up together — treehouse oaths, shared summers, matching scraped knees — even if canon introduced them as adults or enemies.
Alternate Universe - Circus
Runs away with the cast to the big top: trapeze partnerships, ringmaster schemes, sideshow found families, and trains rolling between towns.
Alternate Universe - Coffee Shop
The shorter, enormously popular phrasing of the coffee shop AU, which AO3's tag wranglers funnel into the canonical 'Alternate Universe - Coffee Shops & Cafés'.
Alternate Universe - Coffee Shops & Cafés
The canonical home of the legendary coffee shop AU, where one character works the espresso machine and another becomes a suspiciously frequent customer.
Alternate Universe - College/University
Drops the cast into undergrad life — dorms, all-nighters, terrible dining hall food, and that one 8 a.m.
Alternate Universe - Criminals
The general-purpose crime AU for thieves, con artists, getaway drivers, and heist crews who don't fit the mob or assassin molds.
Alternate Universe - Cyberpunk
Drenches the cast in neon, chrome, and corporate dystopia: hackers, mercenaries, cybernetic augmentation, and megacities where it always seems to be raining.
Alternate Universe - Daemons
Borrows the daemon concept from Philip Pullman's His Dark Materials: every person's soul lives outside their body as a talking animal companion that settles into a fixed form at adulthood.
Alternate Universe - Dark
Signals a universe deliberately crueler than canon — heroes corrupted, hope rationed, institutions rotten.
Alternate Universe - Detective
Hands a character a caseload and a long coat, whether as hard-boiled private eye, brilliant consulting detective, or weary homicide investigator.
Alternate Universe - Different First Meeting
Keeps canon's world entirely intact and changes exactly one thing: how the central characters first encounter each other.
Alternate Universe - Dragons
Puts dragons at the center of the premise: characters as dragons or dragon-shifters, riders bonded to mounts, hoards and the people who get counted as treasure.
Alternate Universe - Dystopia
Builds an oppressive regime around the characters — surveillance states, caste systems, rigged games, forbidden emotions — and watches them comply, break, or rebel.
Alternate Universe - Everyone Lives/Nobody Dies
The Archive's great mercy tag: a universe where canon's body count simply doesn't happen.
Alternate Universe - Fae
Draws on folklore's dangerous fair folk: courts of Seelie and Unseelie, bargains with hidden costs, names withheld, and thanks never spoken aloud.
Alternate Universe - Fantasy
Moves the cast into a secondary world of magic, kingdoms, quests, and mythical creatures — fanfic's version of writing your own epic fantasy novel with borrowed protagonists.
Alternate Universe - Farm/Ranch
Puts characters to work on the land — dawn chores, calving season, a city person inheriting a farm they have no idea how to run.
Alternate Universe - Figure Skating
Puts characters on the ice in a sport fandom knows intimately thanks to Yuri!!!
Alternate Universe - Firefighters
Stations the cast at a firehouse, a setting fandom embraced hard after shows like 9-1-1 and Chicago Fire proved its romantic machinery: communal living between alarms, rescues that go wrong, and the specific terror of watching someone you love walk into a burning building.
Alternate Universe - Flower Shop
The florist AU, sibling to the coffee shop in fandom's small-business romance district.
Alternate Universe - Future
Jumps the setting forward in time — sometimes a full sci-fi future, sometimes just the cast decades older in a changed world.
Alternate Universe - Gang
Organizes characters into street gangs — turf wars, initiation loyalty, leather jackets and territory lines — with a register grittier and younger than mob AUs' organized hierarchies.
Alternate Universe - Gender Changes
The canonical tag covering rule 63 and genderbend traditions: characters written as a different gender than canon, whether always-have-been or newly changed.
Alternate Universe - Ghosts
Makes haunting the premise: a character dead and lingering, a living one who can see them, a house with opinions.
Alternate Universe - Gods & Goddesses
Elevates characters to divinity — gods of death and harvest, rival pantheons, mortals who catch an immortal's eye.
Alternate Universe - Greek Mythology
Pours the cast into the Greek myths specifically — Olympus politics, Underworld bargains, heroes and their dooms.
Alternate Universe - Hanahaki Disease
A universe where the fanon illness Hanahaki exists: unrequited love makes flowers grow in the sufferer's lungs, coughed up petal by petal until confession, requital, fatal bloom, or surgical removal that excises the love along with the roots.
Alternate Universe - Harry Potter Setting
Broader than the Hogwarts tag, this places characters anywhere in the wizarding world — as Aurors, Ministry workers, Diagon Alley shopkeepers, or adult wizards long past their school years.
Alternate Universe - High School
Reimagines the cast as teenagers navigating lockers, cliques, prom, and first love.
Alternate Universe - Historical
The catch-all for any past-era relocation that doesn't have its own decade or period tag — ancient empires, the Renaissance, frontier towns, revolutionary barricades.
Alternate Universe - Hogwarts
Enrolls a non-Harry Potter cast at Hogwarts School of Witchcraft and Wizardry, complete with house sortings, Quidditch tryouts, and detentions in the Forbidden Forest.
Alternate Universe - Hospital
Centers the hospital itself as the setting rather than just the profession — sometimes staff-focused like the medical AU, but just as often built around a patient: one character in a long-term ward, the other a doctor, visitor, or fellow patient.
Alternate Universe - Human
Makes non-human characters human: the android gets a heartbeat, the demon gets a day job, the dragon becomes a guy named Dave with anger issues.
Alternate Universe - Lawyers
Argues the cast into courtrooms and corner offices: prosecutors versus defense attorneys, rival firms, idealists versus sellouts.
Alternate Universe - Magic
Adds magic to a mundane canon or rebuilds the setting around spellcraft — covens, magical academies, hedge witches in modern apartments.
Alternate Universe - Magical Realism
Threads the impossible through ordinary life without explanation or surprise: a house that rearranges its rooms when someone is sad, rain that follows one person, a grandmother who has always been a ghost.
Alternate Universe - Medical
Recasts characters as healthcare workers — surgeons, nurses, paramedics, residents running on no sleep.
Alternate Universe - Medieval
Sends characters back to castles, keeps, and muddy villages — knights and squires, lords and healers, tourneys and sieges.
Alternate Universe - Mermaids/Mermen
Sends at least one character beneath the waves — rescued sailors, voices traded to sea witches, fishermen pulling up more than fish.
Alternate Universe - Military
Enlists characters into armed service — boot camp, deployment, command structures, and homecomings.
Alternate Universe - Mob
Reorganizes the cast into organized crime: dons and capos, enforcers and accountants, loyalty oaths and territory wars.
Alternate Universe - Modern Setting
The go-to tag for transplanting characters from a historical, fantastical, or futuristic canon into the present day.
Alternate Universe - Modern with Magic
The canonical tag for present-day settings where magic exists — historical-fantasy casts moved to today while keeping their powers, or modern AUs with an arcane layer added.
Alternate Universe - Modern: No Powers
A combined canonical tag, especially entrenched in MCU fandom, for stories that are simultaneously present-day and power-free.
Alternate Universe - Musicians
Casts characters as music-makers outside the band format — concert pianists, conservatory students, buskers, session players, producers.
Alternate Universe - Mythology
The wider mythological umbrella for AUs drawing on Norse, Egyptian, Celtic, Japanese, or any other tradition — or blending several into something new.
Alternate Universe - Neighbors
Installs the love interests on opposite sides of a wall, hallway, or fence and lets proximity do its slow work.
Alternate Universe - No Powers
Strips superpowers, magic, or supernatural abilities from a canon that normally runs on them.
Alternate Universe - Noir
Lights the story in venetian-blind shadows: a world-weary private investigator, a client who's trouble, rain on the office window, and a city rotten from the top down.
Alternate Universe - Office
Confines the cast to cubicles, conference rooms, and break-room politics.
Alternate Universe - Pirate
Takes to the high seas with characters reimagined as captains, crews, navy pursuers, and tavern contacts in port.
Alternate Universe - Police
Puts characters in uniform or detective shields: precinct partners, beat cops, internal affairs friction, the works.
Alternate Universe - Pornstars
Places characters in the adult film industry, typically as performers cast opposite each other.
Alternate Universe - Post-Apocalypse
Set after civilization's collapse — plague, war, climate ruin, or unspecified catastrophe — with the cause often less important than the wreckage.
Alternate Universe - Prison
Locks characters inside the carceral system as inmates, guards, cellmates, or visitors.
Alternate Universe - Regency
Transplants the cast into early-1800s England as imagined through Austen and Bridgerton: marriage marts, scandalous waltzes, entailed estates, and reputations that can be ruined by a single carriage ride.
Alternate Universe - Reincarnation
Builds the universe on rebirth: characters who died in canon living new lives, lovers finding each other across centuries, or memories of a past life surfacing at the worst possible moment.
Alternate Universe - Robots & Androids
Rebuilds characters as artificial beings — androids discovering deviancy, robot companions outliving their owners, machines wondering if what they compute is feeling.
Alternate Universe - Rock Band
The louder, leather-jacketed sibling of the band AU, specifically rock and its subgenres: stadium tours, backstage excess, fame's corrosion, and the particular codependency of people who've shared a stage for a decade.
Alternate Universe - Role Reversal
Swaps the positions characters occupy in canon: hero and villain trade places, mentor becomes student, the rescued becomes the rescuer.
Alternate Universe - Roommates/Housemates
Moves the characters in together platonically and waits for the inevitable.
Alternate Universe - Royalty
Recasts characters as monarchs, heirs, consorts, and court schemers, whether in a vaguely medieval fantasy kingdom or a modern constitutional monarchy.
Alternate Universe - Science Fiction
The broad-spectrum SF relocation: cloning facilities, terraforming colonies, AI uprisings, biopunk experiments — anything where speculative technology defines the world.
Alternate Universe - Sex Workers
Casts one or more characters as escorts, cam performers, or other sex-industry professionals.
Alternate Universe - Single Parents
Gives one or both characters a kid and no co-parent, then lets romance bloom around school pickups, playground meetings, and bedtime-story interruptions.
Alternate Universe - Slavery
Builds a setting where slavery is legal and one or more characters are enslaved — science-fictional, historical, or fantasy frameworks all appear.
Alternate Universe - Small Town
Settles the cast somewhere with one diner, one mechanic, and zero secrets — a place where the whole town ships the main pairing before they've had a second conversation.
Alternate Universe - Social Media
Tells its story partly or wholly through platforms — fake tweet threads, group chats, streaming channels, fan accounts that don't realize who they're talking to.
Alternate Universe - Space
Launches the cast off-planet into starships, space stations, colony worlds, or scrappy smuggling vessels.
Alternate Universe - Spies & Secret Agents
Issues the cast codenames and cover identities: rival operatives assigned to seduce each other, handler/agent codependency, double agents lying to everyone including themselves.
Alternate Universe - Sports
Moves the cast into athletics — any sport, any level, from high school teams to professional leagues.
Alternate Universe - Steampunk
Retrofits the world with brass, gears, and impossible Victorian technology — airships, clockwork limbs, tea served at ten thousand feet.
Alternate Universe - Strippers & Strip Clubs
Sets the story in and around exotic dance — a character working the stage or the bar, a regular who only ever comes to talk.
Alternate Universe - Superheroes/Superpowers
Grants powers and capes to casts that never had them, building hero/villain economies from scratch.
Alternate Universe - Tattoo Parlor
Sets the story in and around a tattoo studio, with at least one character as the artist.
Alternate Universe - Teachers
Employs characters at the front of a classroom — colleagues across the staff room, rival department heads, or the music teacher and the gym coach who co-supervise detention.
Alternate Universe - Time Travel
Builds the premise around time displacement — a character thrown into the past or future, timelines rewritten, or travelers meeting people decades out of their own era.
Alternate Universe - Urban Fantasy
Hides a supernatural underworld inside the modern city: vampire-run nightclubs, fae courts in abandoned subway stations, monster hunters with day jobs.
Alternate Universe - Vampire
Turns one or more characters into vampires in a canon that didn't have them, or rebuilds the whole setting around vampire society.
Alternate Universe - Victorian
Corsets the cast into the nineteenth century: gaslit streets, rigid propriety, séances in parlors, and industry's smoke over everything.
Alternate Universe - Vikings
Sails the cast into the Norse world of longships, raids, jarls, and skalds — sometimes rigorously historical, sometimes braided with Norse mythology until gods walk among the raiders.
Alternate Universe - Villain
Flips a hero to the dark side and explores the world that choice creates — sometimes a single divergence that curdled into villainy, sometimes a from-birth reimagining.
Alternate Universe - Werewolf
Gives characters lycanthropy and everything that comes with it: full moons, pack hierarchies, heightened senses, and the constant negotiation between human self and wolf instinct.
Alternate Universe - Werewolves Are Known
A divergence popularized by Teen Wolf fandom in which the supernatural is public knowledge rather than a secret.
Alternate Universe - Western
Saddles the cast up for the frontier: outlaws and sheriffs, ranch hands and saloon keepers, long rides under enormous skies.
Alternate Universe - World War II
Places the cast inside the Second World War — front lines, home fronts, resistance cells, codebreaking huts, field hospitals.
Alternate Universe - Zombie Apocalypse
Throws characters into the end of the world, undead edition: scavenging runs, fortified safehouses, and the constant arithmetic of who can be trusted.
Canon Divergence
A widely used shorthand that wranglers sync into the canonical 'Alternate Universe - Canon Divergence' tag.
Frequently Asked Questions
What does AU mean on AO3?
AU stands for Alternate Universe — any story that changes the canon setting or events. It ranges from minor canon divergence to placing the characters in an entirely different world.
What is canon divergence?
An AU that keeps the original world but changes one or more key events — 'what if this character had lived?' — and follows the consequences. It's popular because it preserves the canon's flavor while rewriting its outcome.
Related Tag Guides
Soulmate AU Tags
Soulmarks, red strings, and bonds — the alternate-universe tags that make destiny part of the romance.
Coffee Shop & Modern AU Tags
The everyday alternate universes — coffee shops, college, high school, no-powers — that relocate canon characters into ordinary life.
Crossover & Fusion Tags
When two fandoms collide — crossovers, fusions, and shared-universe mashups.
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