How to keep AI characters consistent

Why drift happens

Two mechanisms. The first is context: everything the model knows about your story has to fit in a window, and as the story grows, early material gets summarised or dropped. The details that go first are the small ones — which is exactly where character lives.

The second is the pull toward the average. Every generated sentence is drawn slightly toward the most typical version of itself, and over a long story those small pulls accumulate. Distinctive characters become generic ones not in a single step but by a thousand tiny reversions.

Both mechanisms mean the same thing in practice: distinctiveness decays unless it's actively refreshed.

A worked example of drift

It helps to see the failure happen, because it's gradual enough that people usually notice three chapters after it started.

Chapter one, as prompted: a domme who never repeats herself, is faintly amused by everything, and has a job she cares more about than she cares about the scene. The model writes her well — the amusement comes through, she gives an instruction once, she checks her phone mid-scene.

Chapter three: the amusement is still there but has softened into warmth. She's repeated an instruction once, gently. The job hasn't been mentioned. Nothing is wrong yet and nothing you'd complain about.

Chapter five: she is warm, encouraging and entirely focused on him. She explains herself. She asks whether he's all right twice. The job does not exist. She has become the generic supportive partner that the model's training pulls everything toward, and the specific woman you started with is gone.

Chapter seven: you notice, and you can't work out when it happened, because there was never a chapter where it went wrong.

This is why the corrections in this article are all preventative rather than remedial. Once drift has run five chapters, the accumulated context is against you — the model is now being consistent with the wrong version, and pulling it back takes more work than never letting go.

1. One behavioural anchor per character

Give each character a single specific behaviour rather than a description. "She never repeats herself." "He apologises when he's angry." "She touches the key on her necklace when she's thinking."

Behavioural anchors survive summarisation far better than appearance details, because they generate observable actions that keep reappearing in the text. An eye colour gets mentioned once and dropped; a habit keeps producing sentences.

2. Restate load-bearing facts, briefly

When something from an earlier chapter matters, name it in one clause rather than assuming it's remembered. "She still has the key on the chain." "It's day forty-one." "He hasn't been allowed to speak since Tuesday."

This costs you almost nothing and prevents the specific failure that breaks immersion hardest — the story contradicting itself about a thing you cared about.

3. Keep names unusual and distinct

Two characters called Sarah and Sasha will merge. Two called Calla and Rhodes won't.

Pick names with different lengths, different starting letters and different rhythms. It's a trivially cheap intervention that prevents one of the most confusing failure modes, especially in group scenes.

4. Steer per chapter, not per story

The most effective correction is short and immediate. "More of her, less of him." "She's colder this chapter." "Stop explaining." "He's still angry from last time."

Rewriting your original prompt is far less effective than a five-word steer at the top of the next chapter, because the model weights recent instruction more heavily than old context.

5. Watch for the softening

The most common drift direction is toward niceness. Antagonists become sympathetic, dommes become gentle, morally compromised characters start explaining themselves.

Catch it the chapter it starts. "She has not become nicer. She is exactly as she was in chapter two." One sentence, and it holds for several chapters.

The reason this direction specifically is worth watching: softening is the one drift that feels pleasant while it's happening. A chapter where everyone is a bit warmer reads fine in isolation, which is why it survives review and why people only notice at chapter seven when there's no edge left anywhere in the story.

6. Keep a note outside the story

For anything running past five or six chapters, keep three lines somewhere: the cast with their anchors, the rules established, and the current count of anything being counted.

Paste it back in at the top of a chapter when things start slipping. It's unglamorous and it's the single most reliable fix on this list.

Three lines is genuinely the right length. Longer notes don't get pasted back in, and a note that never gets used protects nothing. The value is entirely in the habit rather than in the completeness of the record.

The three-line story bible

The single most effective technique on this list, and the least glamorous. Keep three lines somewhere outside the story and paste them in when things start slipping.

Line one, the cast: each name with one behavioural anchor and nothing else. "Calla — never repeats herself, faintly amused, cares more about her work. Tom — competent at his job, apologises when he's angry." Resist the urge to write descriptions; anchors are what survive.

Line two, the rules: whatever has been established that constrains the story. "She holds the key. He has to ask by text and wait. Nothing happens on Sundays." These are the things a reader will notice being violated, and they're exactly what falls out of context first.

Line three, the count: any number being tracked, and where it currently is. "Day 41. Fourth time she's moved the date." Numbers are load-bearing in denial, chastity, and any arrangement-based story, and a model will drift them without noticing.

Paste all three at the top of a chapter whenever a story is past chapter five, or whenever a chapter comes back feeling off. It takes ten seconds and it's the difference between a story that holds for twenty chapters and one that dissolves at eight.

Consistency of world, not just people

Character drift gets all the attention, but world drift causes more of the moments that break a reader out, and it's easier to prevent.

Geography goes first. A flat with a bedroom down the hall in chapter one acquires a staircase in chapter four. The kitchen is on a different floor depending on the scene. Nobody plans this and every long generated story does it. Fix: name the space once, concretely and minimally — "a one-bedroom flat, the bedroom off the main room, no stairs" — and restate it when a scene moves.

Time goes second, and it goes badly. Days of the week drift, seasons stop advancing, and a story explicitly set over six weeks will have three consecutive chapters that are all 'tonight'. The fix is the counting habit: put the day at the top of the chapter and the model will keep it.

Objects go third. The key on the necklace becomes a key in a drawer. The contract on the table is never mentioned again. Props established early carry enormous emotional weight in this genre precisely because they recur, and a model will drop them unless they're reintroduced.

And rules go last but hurt most. An arrangement with four rules will have two of them silently repealed by chapter six, usually the two that constrain the story most — which is to say, the two doing all the work. Of everything on this list, the rules are the thing most worth keeping in a note and pasting back in.

The general principle: anything that constrains the story will decay, because constraint is what a model's pull toward the average erodes first. The things that make your story specific are exactly the things you have to keep restating.

Consistency in group scenes

Multi-character scenes have their own failure mode and it's worse than ordinary drift: characters quietly merge, or one silently leaves the room.

The merge happens when two characters have similar names, similar registers, or no distinguishing anchors. In a three-person scene the model will frequently start attributing actions to whichever name it used most recently. The fix is upstream: names with different lengths and different starting sounds, and one anchor each that produces visibly different behaviour.

The disappearance is more insidious. In a threesome or group scene the model will focus on two people and let the third become furniture — present in the setup, absent for four paragraphs, reappearing without explanation. Readers feel this even when they can't articulate it, and it's the main reason group scenes read as flat.

The correction is a standing instruction: "place all three in every beat, even the one not being touched." It sounds mechanical and it works. What the third person is doing while not being touched — watching, waiting, deciding, adjusting something — is frequently the most charged material in the scene, and the instruction is what makes the model write it.

For anything above three people, anchor to one point of view and let the others blur deliberately. That's not a limitation to work around; it's how good group scenes are written by humans too.