Interactive fanfiction: replaying a story you already love

Written fanfiction answers that question once, in a fixed direction the author picked. Interactive fanfiction lets you ask it repeatedly, and take the answer somewhere the author never planned, because there is no author waiting at the end of the branch.

That is a genuinely different reading experience, and it only works if one thing is true: the world has to hold.

The whole difficulty is the canon

A generic AI story only has to be internally consistent. It invents the world as it goes, so it can never contradict a source it does not have.

Fanfiction has a source, and the source is exactly why you are here. If a character behaves in a way readers of the original would find impossible, the fantasy collapses immediately. You did not want any story in that setting. You wanted that world, with your choices in it.

The pleasure of interactive fanfiction is not doing anything. It is doing something the world then has to react to, in character.

So the system has two obligations at once, and they pull against each other. It has to honour what is fixed, and it has to genuinely let go of what is not. Systems that only do the first are on rails. Systems that only do the second are writing generic fiction with borrowed names, which is the more common failure and the more disappointing one.

A world is not its text

"Import a world" sounds like uploading a file. But the author's sentences are the least useful thing in a book for this purpose. What a playable world needs is the structure underneath them: who the people are and how they stand toward each other, what has already happened and which parts of it are load-bearing, what is not yet known and by whom, and the rules of the place that have to keep holding no matter what you do.

Notice what is absent from that list: the prose. This matters for two reasons, and they happen to point the same way. It is the position that keeps the whole exercise legally defensible, since a high-level abstraction of a work is not the work. And it is also simply the more useful artefact, because a system cannot reason about a paragraph, only about what the paragraph established.

One detail worth pulling out, because getting it wrong is common: relationships have a direction. How much A trusts B and how much B trusts A are separate facts that move independently, and a system that collapses them into one number cannot represent a betrayal — which is, fairly often, the reason you came to the story.

Knowledge has a direction too: what each character knows, and does not, is what makes a secret or a betrayal possible at all. We wrote about it in theory of mind in fiction.

Drift, and why some of it is the point

Once you start making choices, your version and the original separate. That separation is the product. The interesting question is what the system does about it.

Doing nothing gives you an unrecognisable world in ten chapters. Pulling hard on the reins gives you a book you are watching rather than playing. What is needed is closer to gravity: your version can travel a long way from the source, and the pull back toward the fixed points stays present the whole time, so the story keeps finding its way to the moments that made it matter, arriving at them differently because of what you did.

This is the least finished part of what we have built, and we would rather say so than imply otherwise. Getting a story to come back to a fixed point reliably, rather than usually, is an open problem here.

You can try one today

Nine of the worlds in Nostyss's picker were written for Nostyss. One was not: it was imported from an existing series, with its canon extracted the way described above, and it is the only one where the fidelity and drift machinery is exercised against a real source.

It is there to be judged, not admired. Play a few turns, contradict something the original established, and watch what the world does about it. Importing your own worlds is the feature this one exists to demonstrate.

See whether it actually remembers

Ten worlds you can start without an account. Play a few chapters, contradict something you established earlier, and watch what the world does about it. That test is the honest way to judge any of this.

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