AI Game Master and Narrator for RPGs and Solo Campaigns

Playing a tabletop RPG alone means missing the best part of the evening: the person across the table who describes the room, laughs at the daft plan and makes the dice matter. Neocortex lets you build an AI game master and narrator who knows your setting, speaks in a voice of its own, paces each chapter, and asks your game to roll dice or spawn an encounter when the story calls for it.

What it looks like

The Ashfall Marches is a solo campaign in an original dark fantasy world: river kingdoms under a sky that never quite clears of ash. The player is Brother Aldric, a disgraced knight-monk trying to reach the Drowned Chapel before nightfall. The narrator is the Lantern-Keeper, a gravelly old storyteller with a dry sense of humour who has seen many knights fail.

Tonight's chapter has three beats: find the chapel, ring its bell, escape the valley. The player gets creative:

Player: I climb the bell tower from the outside and cut the rope, so the bell falls and wakes the whole valley. Lantern-Keeper: The stones are slick with river moss. Let's see if your hands remember their training.

That reply carries a ROLL_CHECK action aimed at the bell tower. The game rolls with its own rules, gets a 7 against a difficulty of 12, and sends the result back as an event: "Climb check failed, Aldric falls into the nave."

Lantern-Keeper: Halfway up, a stone gives. You land hard on the flagstones of the nave, and somewhere beneath the floor, something answers the noise.

This time the reply carries SPAWN_ENCOUNTER aimed at the crypt below, and the game drops a group of drowned pilgrims into the scene. The flow has already passed its chapel_found Checkpoint. The bell can wait.

The split matters. Your game still owns the rules, the dice, the hit points and what is true in the world. The narrator describes, reacts and asks for things; your code decides whether they happen.

How Neocortex makes it work

• A narrator character. In the visual editor, the Lantern-Keeper gets a personality, a way of speaking, a description of the world he narrates and a clear rule: describe outcomes, never decide them.
• Knowledge base. Upload the setting bible as PDF or TXT documents: factions, places, history, the names of the dead saints. Free includes 1 upload, Starter 5, Pro 20 and Team 100, so a large setting can be split across many files.
• Conversation Flows. Each chapter is a flow with a Start node, a Checkpoint per beat and End nodes for how it can finish. The narrator steers toward the next beat, and flowState tells your game when to advance. Flows are on every plan.
• Actions. ROLL_CHECK, SPAWN_ENCOUNTER, AWARD_ITEM and END_SCENE come back with a target. Your game's rules engine runs them.
• Events. Dice results, combat outcomes and state changes go back in as events, so the next line of narration describes what your rules actually decided.
• Metadata. Send the places, people and items in the current scene, so the narrator refers to the things that exist in your game state.
• Voiced narration. Every reply streams as speech. Design a custom voice from a text description, like "an old storyteller with a low, tired voice", or clone one from a short sample, on Pro (5 voices) or Team (20).
• Session memory. Keep the campaign's sessionId with the save, and the next evening resume the player's session where the chapter left off.

Ideas to build

A horror narrator who knows when to whisper. In a first-person horror game, the narrator is the voice in the player's head. Events like "the player has not seen light for four minutes" shift the emotion tags toward fear, and the delivery gets quieter and closer as the player goes deeper.

A commentator for a roguelike. A sardonic voice that watches each run. Send events like "the player died to the third boss again" or "the player picked the cursed relic", and resume the player's session between runs so the jokes build on earlier deaths.

An audio adventure you play by talking. For a voice-first game on mobile, the player speaks their choices through speech-to-text and the narrator answers in streamed audio. No screen needed beyond a map, and in more than 20 languages.

A one-shot generator for game nights. A narrator who runs short self-contained adventures from a shelf of setting documents. Your game picks the scenario and its flow, the narrator sets the scene, and the player sees a new story every time.

Building it

AI narrators run through the Unity SDK, the Unreal Engine plugin with Blueprints, the Godot addon (beta) or the Web API from any engine, including text-first and browser games.

1. Write the setting bible and upload it to the narrator's knowledge base, split into readable documents.
2. Design the narrator: personality, narration style, voice, and firm rules about what the narrator may and may not decide.
3. Author an action for every rules moment your game handles: checks, encounters, loot, scene endings.
4. Build one flow per chapter with the beats the story must hit.
5. Play a session in the dashboard, trying odd plans to see how the narrator handles them.
6. Wire the loop: actions to your rules engine, results back as events, flowState to chapter progression.

Tell the narrator in its design to always ask for a roll when an outcome is uncertain, instead of narrating success. That keeps the dice meaningful and your rules in charge.

The narrator is one of our AI NPC, ambient AI and voice command use cases. For the characters the narrator introduces, read AI quest giver NPCs and AI suspects for detective games. The interactive storytelling page and the API reference cover the rest. Start with one chapter, one roll and one encounter.

Checked October 2026.

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