The Most Popular Fandoms for AI Fan Fiction

The top 15 fandoms people write AI fan fiction about

Here is the ranking, by number of fan fiction books made with Inkfluence AI, after merging name variants (so "Naruto" and "Naruto (Masashi Kishimoto)" count together):

Beyond the top 15, the Inkfluence AI data keeps going through Game of Thrones, The Boys, Teen Wolf, House of the Dragon, Batman, Stranger Things, Fourth Wing, Demon Slayer, Attack on Titan, and hundreds more, all the way down to single-book fandoms.

Why is Harry Potter the runaway #1?

On Inkfluence AI, Harry Potter is not just first, it is first by a distance: 261 books, roughly twice the next fandom. That mirrors the wider fan fiction world, where Harry Potter has long been one of the largest single communities on archives like Archive of Our Own. The reasons are structural. It has a deep, richly mapped world with dozens of named characters and locations, a fanbase that has been writing for over two decades, and an enormous canon of established tropes for new writers to build on. When someone reaches for an AI tool to write fan fiction, the universe with the most existing scaffolding is the easiest place to start, and Harry Potter has more scaffolding than anything else. It is worth being precise about the size of that lead: at 261 books Harry Potter is 28.8% of the entire top-15 pool, and more than double My Hero Academia at 123. No other fandom in the dataset comes close to that share.

Why does anime dominate everything after it?

The four fandoms right after Harry Potter are all shonen anime: My Hero Academia (123), Naruto (99), One Piece (62), and Jujutsu Kaisen (57), with Demon Slayer and Attack on Titan close behind. Anime fandoms are huge, young, intensely online, and built around large casts and open-ended worlds, exactly the conditions that produce a lot of fan fiction. They also skew toward the demographics most comfortable experimenting with AI writing tools. Add games with anime-style worlds like Genshin Impact (28) and Fate/Grand Order, and anime-adjacent stories make up the single largest slice of AI fan fiction after Harry Potter. If you write in this space, Inkfluence AI keeps a big cast and their voices consistent across chapters, which is usually the hardest part. Grouped rather than listed individually, the four shonen titles in the top five reach 341 books between them, which is more than Harry Potter manages alone. Anime is the largest category here even though no single anime is the largest fandom.

It is not just books and anime: TV, games, and K-pop

The data spans every kind of media. TV is strong, with The Vampire Diaries (28), Stranger Things, Teen Wolf, House of the Dragon, Supernatural, and The Boys all featuring. Games show up through Genshin Impact, Fate/Grand Order, and even the horror game Poppy Playtime. And music fandom is real: on Inkfluence AI, BTS sits in the top 10 with 37 books, a reminder that K-pop "real person" fan fiction is a major category. Book series remain a backbone too, from Percy Jackson and A Song of Ice and Fire to the newer Fourth Wing, which already has its own AI fan fiction within a couple of years of release.

How common is fan fiction among AI books?

About 5.2% of all 81,100 books created with Inkfluence AI are fan fiction set in an existing universe. That makes it a passionate niche rather than the main use of AI for books, which is led by practical non-fiction and original fiction (see what people write with AI). But the 1,892 distinct fandoms tell the more interesting story: fan fiction has an enormous long tail. For every Harry Potter with dozens of books, there are hundreds of universes with just one or two, from indie games to childrens cartoons to a single beloved novel. For context on what the other 94.8% looks like, our study of what people write with AI breaks the whole corpus down by category.

The surprising fandoms in the long tail

The most fun part of the 1,892 fandoms on Inkfluence AI is what shows up that you would not predict. Poppy Playtime, a horror video game, has more AI fan fiction than some blockbuster films. Steven Universe and Avatar: The Last Airbender prove animated series travel well. Fate/Grand Order shows how deep gacha-game lore runs. And BTS ranking above most movie franchises is a clear signal that "real person fiction" from music fandoms is one of the quiet giants of the genre. The long tail is where fandom gets weird, personal, and genuinely creative, which is exactly why people love it. The arithmetic behind that tail is stark: outside the top 15, roughly 1,877 fandoms share 3,324 books, an average of fewer than two books each. If you write for a universe nobody has covered, there is a good chance you are writing the only AI fanfiction that exists for it.

Can you write and sell AI fan fiction?

You can absolutely write it. Non-commercial, transformative fan fiction shared freely is the basis of the huge communities above, and Inkfluence AI makes it faster to draft a multi-chapter story in any of these worlds. Selling it is the line to be careful about: the characters and worlds are copyrighted, so fan fiction lives in a legal grey area and selling work built on someone elses universe can infringe their rights. The practical takeaway from our wider data is that if your goal is to publish and earn, original fiction is the safer path, and it is just as quick to write with AI. Many writers use fan fiction to practise, then carry the skills into original worlds they fully own. The short version is that fan fiction sits under the rights holder's terms, so it is generally fine to publish freely and not fine to sell. If you want to sell what you write, the same tools handle original fiction with the characters and world as your own.

What the shape of the data tells you

The ranking above is the part everyone looks at, but the more useful finding is how little of the corpus it accounts for. Those top 15 fandoms total 907 books, which is only 21.4% of the 4,231 fan fiction books in the study. The remaining 3,324 books are spread across roughly 1,877 other fandoms, an average of 1.77 books per fandom. Fan fiction written with AI is not concentrating around a few safe franchises. It is doing the opposite.

That matters if you are deciding what to write. A crowded fandom is not automatically a bad choice, but it does mean your premise has to do the work rather than the universe. In the long tail, where most fandoms have one or two books total, a competent fic is often the only one that exists for that universe.

Two patterns are invisible unless you group the list. First, the four shonen anime in the top five combine to 341 books, comfortably ahead of Harry Potter's 261. Harry Potter is the biggest single fandom; anime is the biggest category, and those are different claims. Second, Westeros is split across three entries: House of the Dragon (41), Game of Thrones (33) and A Song of Ice and Fire (27). Counted as one franchise that is 101 books, which would place it third overall, ahead of Naruto. How you define a fandom changes the ranking, which is why the methodology below states the merge rules explicitly.

If you are choosing where to start, our guide to the best AI tools for fanfiction covers the practical side, and the AI fanfiction writer handles any of these universes directly.

Methodology

This study is based on all 81,100 books created with Inkfluence AI as of August 2026. When a book is set in an established universe, that universe is recorded on the book. We counted those records (4,231 books carried one), normalized name variants by stripping author and creator suffixes (so "Harry Potter" and "Harry Potter (J.K. Rowling)" merge), and ranked the totals. Counts are exact; the fan fiction share is rounded. Live totals grow daily.

Three limits are worth stating plainly, because they change how the ranking should be read. First, a universe is only counted when the writer recorded one, so books that are unmistakably fan fiction but were never tagged do not appear here; the true share is a floor rather than a ceiling. Second, the merge rules are conservative. We combine name variants of the same title but we do not combine related properties, which is why House of the Dragon, Game of Thrones and A Song of Ice and Fire sit as three separate entries rather than one Westeros total. Third, this is a snapshot of what people chose to write on one platform, not a measure of fandom size in the world. It reflects which universes people reach for when a drafting tool removes the blank page, which is a narrower and more specific question than what is popular.

Sources

• Inkfluence AI first-party data: 4,231 fan fiction books across 1,892 fandoms, of 81,100 total books (August 2026).
• Archive of Our Own (AO3), the largest fan fiction archive, where Harry Potter and major anime are consistently among the most-written fandoms.
• Fanlore: Fan fiction, background on fan fiction as a transformative, largely non-commercial practice.