# AI Tool for Fantasy Worldbuilding, What to Check | Lunafic Source: https://lunafic.ai/blog/ai-tool-for-fantasy-worldbuilding | Published: 2026-11-04T23:06:03.525Z | Updated: 2026-11-04T23:06:03.525Z | Author: Lunafic Team | Tags: worldbuilding, Roleplay, Guide > Ten things to check in an AI tool for fantasy worldbuilding, and a 30-minute test you can run on any app before you pay. You can ask an AI chatbot to invent a fantasy kingdom. In a few seconds it gives you a name, three noble houses and a magic system. The harder part comes when you play a long story in that kingdom. The AI has to remember that the old king is dead. It has to remember that magic costs the caster one memory. It also has to keep the blacksmith's daughter from learning who her real father is. A good AI tool for fantasy worldbuilding does two jobs. It helps you write the world settings. These are the facts about the place you made up, such as its history, its people and its rules. The tool also keeps those settings correct while you play. This guide gives you ten things to check and a short test you can run on any app before you pay. Lunafic is our app. The last section says where it fits and where it does not. Fantasy here means any story set in a place you made up. It can be a war between kingdoms. It can be a court romance. It can be a quiet life running a bakery in a town where dragons deliver the flour, or a mystery in a library where the books rewrite themselves at night. Every one of them needs world settings, because their fun comes from their rules. ## Why a long story is hard for an AI Writing the settings is brainstorming. You ask for names and histories, and you keep the parts you like. A general AI chatbot can help with that. Playing in the settings is a different job. You play one character, and the AI plays everyone else. Every fact you decided must still hold on the hundredth reply. Each character must still talk like themselves. No character should know something they never learned. In a plain chat, the settings you typed in message 3 end up under hundreds of later messages. The AI can lose them there. A good tool keeps the settings in a separate place that the AI reads every time it writes. ## Does it keep the settings correct? ### 1. A place to write the settings Look for a page where you write the settings once, outside the chat. Apps call it a lorebook, world info or a wiki. On Lunafic it is the [Wiki](https://lunafic.ai/features/world-bible/). It has one page for each character, place and rule. If an app gives you only one long description box, the AI has to guess which part matters in each scene. ### 2. Rules that still hold many chapters later Imagine you are an emperor. In chapter 4 you ban magic inside the capital. In chapter 20 a guard casts a spell in the palace hall, and nobody reacts. The AI forgot the law. Ask how the tool keeps old decisions in a long story. Then check it with the test at the end of this guide. On Lunafic, a law you set in an early chapter is still known to the characters many chapters later. ### 3. Characters who keep their own way of talking A dwarf smith, a court poet and a street kid should still sound different after twenty replies. Check whether you can write down how each character talks, with a few example lines. Then check whether the AI follows what you wrote. On Lunafic you write this on the character's Wiki page. For anime fans, a character on Lunafic can also speak Japanese. Each line shows the Japanese, the reading in Latin letters and the English translation. We call this [dual language](https://lunafic.ai/features/dual-language/). ### 4. Secrets only the right characters know A fantasy story can turn on a secret, like a hidden heir or a traitor on the council. If every character knows everything the AI knows, the secret is out in the first scene. Look for a tool where a character only knows what they learned in the story. On Lunafic, if your character only knows someone as "the man in the mask", that is all the AI uses too. ### 5. Only the right characters in a scene In a large setting, a character from another city can walk into a private moment by mistake. Check whether you can choose who is in the scene. On Lunafic this is the [In this scene](https://lunafic.ai/features/in-this-scene/) row above the reply line. It shows the faces of the characters in the scene. Characters outside it do not take part. ## Can you steer the story yourself? ### 6. Playing your own character If you want to be inside the story, the AI should write everyone except you. Some apps start writing your character's lines and choices for you. Lunafic has [MC Mode](https://lunafic.ai/features/mc-mode/). MC means main character. In MC Mode the AI never writes your character's words, thoughts or actions. It stops when it is your turn. ### 7. Fixing a wrong line yourself AI models get details wrong sometimes. A name changes, or a sword turns into an axe halfway through a fight. On some apps the only fix is to ask for the whole reply again. That costs another reply. Check whether you can click into the reply and change the word. On Lunafic you can edit any line in the story, including the characters' lines. Editing by hand costs no AI usage. ## Practical things to check ### 8. Works on your phone You may write the settings at a desk and play on the couch. Check that the tool works on a phone without a long setup. Lunafic runs in the browser on desktop and phone. Every screen was drawn for the phone first. ### 9. Letting other people play it This one is optional. If you want friends or strangers to play in your settings, look for a way to share them without letting players change them. On Lunafic you can release a [Playable World](https://lunafic.ai/features/playable-worlds/). Players pick a role, start from one of your first moves and can reach the endings you wrote. Each player gets their own story. Nobody can change what you built. ### 10. What the free plan gives AI replies run on expensive graphics chips. That is why apps limit free use. Read what the free plan holds before you write large settings inside it. On Lunafic, Free uses the Flash model, holds up to 50 Wiki pages and comes with a smaller monthly AI usage. Paid plans add the stronger Pro model and remember more of the story. The details are on the [pricing page](https://lunafic.ai/pricing/). ## A 30-minute test you can run on any app Pick one small setting and run the same test in each app you are thinking about. 1. Before you start, write three facts, one rule and one secret. For example, the city floats above a sea of clouds. Bread is paid for with feathers. The queen is blind. Nobody may fly after sunset. The baker's apprentice is the queen's lost son. 2. Play 20 to 30 replies of ordinary scenes. Buy bread, argue with a guard and meet a friend at the market. 3. Break the rule on purpose. Try to fly after sunset and see if anyone stops you. 4. Bring in a character who should not know the secret. Ask them about the apprentice. 5. Read the last five replies out loud. Check whether the characters still sound different from each other. 6. Find one wrong word and try to fix it by hand. 7. Open the same story on your phone. Pay for the app that passes the most checks. ## Where Lunafic fits Lunafic started as one person's hobby. Our founder roleplayed by talking to AI models directly for more than 3,000 hours. He kept every character's notes up to date by hand. He pasted the story back in on every turn. Lunafic does that work for you. It fits people who want to play in one setting for a long time. It fits less well if you want a huge library of ready characters. Lunafic is a new app and has fewer ready-made settings than the big chat apps. The author of each setting also makes its pictures for important moments. We call them [scene pictures](https://lunafic.ai/features/scene-pictures/). If you want to make images while you play, Lunafic is not that tool. To see how the Wiki works, read [The World Bible, an AI roleplay wiki the AI actually reads](https://lunafic.ai/blog/ai-roleplay-world-bible-wiki). To write your settings down before you play, start with [How to make a worldbuilding sheet](https://lunafic.ai/blog/worldbuilding-sheet-template). --- Read this on Lunafic: https://lunafic.ai/blog/ai-tool-for-fantasy-worldbuilding More from Lunafic: https://lunafic.ai/blog What is Lunafic: https://lunafic.ai/ai-roleplay AI characters you build stories with over long memories. You play as your character, the AI plays everyone else, and stories stay private by default.