ChatGPT as Your DM: the Prompt That Actually Works

Step 1: paste this and start playing

You are a strict but fair TTRPG dungeon master. Run this campaign under these rules:

[SETTING]: Low-magic medieval fantasy. An orc raid just burned the border village; survivors crowd the town. (← replace freely)
[MY CHARACTER]: (name / ancestry / class / one-line background — e.g., Karr, human ranger, searching for his missing sister)

DM rules:
1. Each turn: describe the scene and NPC reactions (under 120 words), end with 3 options, and always allow a free-typed 4th action.
2. Any action that can fail: declare "Check: D20, DC X" BEFORE rolling, then apply the rolled result honestly. Never soften an outcome for story convenience.
3. Maintain my character sheet (HP / inventory / gold). Announce every change.
4. NPCs have their own motives and do not exist to help me. Reckless actions have consequences.
5. Every 10 turns, output a [SAVE SUMMARY]: plot so far, character sheet, open threads. I will paste it into a new conversation to continue.

Begin: describe the opening scene.

That's it — you're playing. Swap the [SETTING] line for cosmic horror, cyberpunk, wuxia, whatever you like.

Three tweaks that double the experience

• Enforce the dice. Rule 2 is the soul of the template. Without it, you can talk your way past anything and tension dies. When you notice outcomes getting soft — and you will — re-paste the rule.
• Use the save summary. Rule 5 is your defense against amnesia: long chats forget who you spared last week. Store summaries yourself; paste into a fresh chat to "load your save."
• Direct the prose. Too chatty? Cut the word limit to 80. Want novel-feel? Raise it to 250 and ask for sensory detail. The DM's voice is a parameter you control.

Honesty time: the three walls

Every ChatGPT campaign eventually hits the same three walls — they're engine problems, not prompt problems:

1. Amnesia. Context windows are finite. Save summaries preserve the plot's spine, not its flesh: the innkeeper you owe money, the seventh item in your pack — gone.
2. Imaginary dice. Even when it "rolls," the model is narrating a roll. After your third failure it will quietly start rooting for you. No real mechanics, no real risk.
3. A frozen world. Nothing happens unless you type. No faction goes to war while you sleep; no price moves because you cornered a market. It's a narrator, not a world.

When to graduate to a real engine

If you play weekly one-shots, ChatGPT is genuinely enough. But if you want a character that survives months, failure that actually costs you, and a world that runs without you — that's what dedicated engines are for: state lives in a database (no amnesia), checks run on real numbers (no mercy), and the world keeps simulating between your turns.

Blade RPG is our version of that: a browser AI RPG where the AI narrates on top of a persistent engine — permadeath, economy, injuries, NPC memory. Worth setting expectations honestly, because it is not a drop-in replacement for a ChatGPT campaign: the English edition is a cultivation (xianxia) roguelike with permanent death, not a freeform DM. You roll a spirit root once, climb a 45-rank realm ladder, and when you die that run is over. English client at e.bladerpg.com, 40 free turns, no card, no download.

If what you want is specifically a flexible DM for your own setting, ChatGPT with the prompt above is genuinely a better fit than we are, and so are several of the dedicated tools on our comparison page. We're the answer to a narrower question: what if the world could actually refuse you, and losing meant something?

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Related: AI Dungeon alternatives · Wuxia games guide · Xianxia games guide