AI Dungeon vs Isekai Zero (2026): Which One Holds a Long Story Together?
Access disclosure: Isekai Zero gave us free Arcane credits to play the game for our review of it. No conditions were attached to our coverage, and this comparison is independent and unpaid.
AI Dungeon and Isekai Zero are both story games built on worlds that other players wrote, and the main difference between them is that Isekai Zero remembers a long story far better while AI Dungeon leaves you far more free to wander.
They are closer rivals than they look. Both let you pick a world from a community library. Both let you choose which AI model writes your story. Neither is a rules-heavy game. Where they split is on memory, on how they charge, and on what happens when you walk away from the plot.
The Short Version
| AI Dungeon | Isekai Zero | |
|---|---|---|
| Overall | 2.6 | 3.4 |
| Memory & Continuity | 3 | 4 |
| Player Agency | 4 | 3.5 |
| NPC Fidelity | 3 | 3.5 |
| Mechanical Depth | 2 | 2.5 |
| Determinism & Fairness | 2 | 2 |
| Longevity | 2 | 3.5 |
| Signature Design | 2 | 4.5 |
Scores from each platform’s entry in our directory, on our seven-axis methodology. Isekai Zero is fifth of the twenty-eight platforms on our benchmark.
| AI Dungeon | Isekai Zero | |
|---|---|---|
| What you start from | A scenario, or nothing | A storyline with a world, a premise and a cast |
| Free play | No turn limit, nine story models | Free models, plus a free currency you earn |
| How it charges | Monthly membership, $14.99 to $99.99 | By the message; 100 Arcane = $1 plus a fee |
| What paying buys | More models and more context | Premium models with the largest context |
| Memory | Story Cards, Plot Essentials, Author’s Note, Memory Bank | Chapters and arcs you can read and rewrite |
| Can you see what a message cost? | No per-message price; play is not metered | Yes, on every message |
| Dice | None built in | A d20 referee on some storylines |
If you only read one line: Isekai Zero for one long story that remembers, AI Dungeon for total freedom at no cost per message.
What Each One Is
AI Dungeon, made by Latitude, started this category in 2019. You pick a scenario from a large library or begin with a blank page, choose a model, and play a story in any genre. It has no dice and no character sheet unless a scenario’s author scripts them in. Its strength is that it will follow you anywhere. Our review covers it in full.
Isekai Zero, made by ARX Media Sdn Bhd in Malaysia, is built around storylines. A storyline is closer to a small game than to a character card: its creator writes the world, the opening scene, a main cast and sometimes a set of rules, and you choose who you play in it. As the story runs, the game adds supporting characters of its own. You can read the same story as plain chat, with a narrator voice, as a light novel with illustrations, as manga panels, or as a visual novel with character sprites. Some storylines are rated 18+ and sit behind an age check. Our Isekai Zero review has the full account.
Memory: The Axis That Separates Them
Isekai Zero scores Memory & Continuity — 4. AI Dungeon scores Memory & Continuity — 3. One point does not sound like much. In play it was the biggest difference between the two.
Isekai Zero. In our play it forgot only small things, details that did not matter to the story. It never forgot something that did. It is not perfect: the small details it lost produced one or two strange messages. But only one platform on our board scores higher on this axis.
The system behind it is one you can open:
- Every twenty messages can be condensed into a chapter, a written summary of those messages.
- Every ten chapters can be condensed again into an arc.
- You can open any chapter, read it, rewrite it, or ask for it to be written again.
The studio’s own example took a story from about 40,000 tokens of context to just under 16,000 with one arc. Its documentation puts model context limits between 10,000 and more than 131,000 tokens, depending on the model you choose. In the chat settings the game shows how large your context has grown, next to the limit of the model you are using. You can see a story getting close to the edge before it happens.
AI Dungeon. It gives you four tools, each with its own job:
- Plot Essentials holds what is always true, and is sent on every turn.
- Story Cards hold notes about people and places, and are sent only when a trigger word appears.
- Author’s Note is a short reminder placed right before your latest action.
- The Memory Bank stores memories of what has happened: 25 for each adventure on the free tier, up to 800 on the top tier.
You can also press the last response and choose View Context to see exactly what the AI received. These are good tools, and our guides to Story Cards and to AI Instructions, Plot Essentials and Author’s Note explain them.
The limit is how much the AI can read at once. On 2 October 2026, AI Dungeon’s membership page gave most free models 4k tokens of context, which is roughly 3,000 words for the story, the instructions and the notes together. Paying raises it:
| Wanderer | Journey | Legend | Mythic | Ultimate | |
|---|---|---|---|---|---|
| Price per month | Free | $14.99 | $29.99 | $49.99 | $99.99 |
| Headline context | up to 4k | up to 8k | up to 16k | up to 32k | up to 32k on DeepSeek |
| Memories per adventure | 25 | 100 | 200 | 400 | 800 |
From AI Dungeon’s membership page, read on 2 October 2026. Each model has its own allowance; our membership guide lists every one.
So the two memories are built from the same idea, which is notes and summaries standing in for text that no longer fits. The difference is in the amount of room and in how much you can see. On Isekai Zero the summaries are yours to read and correct, and the context numbers are on the screen. On AI Dungeon you manage more boxes inside a smaller window, unless you pay for a larger one.
For why every AI game has this problem, see why LLMs forget.
Freedom: AI Dungeon’s Lead
AI Dungeon scores Player Agency — 4. Isekai Zero scores Player Agency — 3.5.
On the first half of this axis they are level. Neither one puppets you. By default Isekai Zero does only what you write, and there is a setting you can turn on if you want the AI to fill in or polish your actions. AI Dungeon follows whatever you type.
The half point is lost on railroading. An Isekai Zero storyline has a set cast and it develops its plot points naturally, which is good. The problem came when we decided to leave them behind. The game let us go. But the story kept telling us about the plot points and the cast members we had walked away from, even when we wanted nothing more to do with them.
AI Dungeon does not do this. Type something absurd and it goes with you, and no cast pulls you back. That is why its reputation rests on strange, dreamlike stories that went somewhere no designer planned.
This is also the natural cost of what each one starts from. A storyline with a written cast gives you better characters and a reason to care. It also gives the story something to drag you back to. A blank page drags you nowhere.
Our guide to player agency in AI RPGs explains the axis in full.
Characters
Isekai Zero scores NPC Fidelity — 3.5. AI Dungeon scores NPC Fidelity — 3.
Isekai Zero’s characters surprised us more than once. They made decisions from their own personality, not from what was right or wrong. They are not sorted into good people and bad people, which is how most of this field writes its casts. They sit in shades of grey.
What held the score down is that they never change. Someone written as an undefeated fighter kept acting confident and undefeated after losing every fight. The only way we found to change a character was to add a note to the storyline’s prompt ourselves.
AI Dungeon writes characters as part of a world and not as authored individuals. That serves the story, and it rarely produces someone you remember.
Fairness and Rules: Level, and Low
Both score Determinism & Fairness — 2, and for the same reason: the narrator gives too much power to what the player writes.
On Isekai Zero we told the game we would get a guildhouse. The story gave us one, with many facilities, and it cost us nothing. The narration said our party had paid for it with money we had earned. It did not name a price or take any money from us. We could also create objects just by saying that we had them.
On AI Dungeon the same thing happens by design. With no rules underneath, the world accommodates everything, and succeeding feels much like the platform agreeing with you.
On rules, Isekai Zero scores Mechanical Depth — 2.5 and AI Dungeon scores Mechanical Depth — 2. Isekai Zero is a little ahead because some storylines come with a referee called the Dungeon Mind. It rolls a d20 on the server, keeps a character sheet with health, conditions and levels, and can refuse an action that breaks the storyline’s rules. Its documentation says it will not let you give yourself +10 Strength or set your health to full. In our play, money and property had no such guard. AI Dungeon has no dice built in; a scenario’s author can add mechanics with scripting.
Neither is the game to choose if you want everything you own to be earned. Our guide to difficulty in AI RPGs explains why this is hard across the whole category.
What Each One Costs
They charge in opposite ways.
AI Dungeon is a subscription, and free play is not rationed. The free tier has no turn limit. Latitude’s help centre says: “AI Dungeon is a free-to-play game, no matter what device you’re playing on”. Memberships cost $14.99, $29.99, $49.99 and $99.99 a month, and they buy more models and a larger context. You know what you will pay each month, and you never think about the cost of one more turn.
Isekai Zero charges by the message, and does not sell a subscription. Figures from its pricing and credit documentation, checked on 24 September 2026:
| Free models | Mana | Arcane | |
|---|---|---|---|
| Cost | Nothing | Nothing; earned by daily check-in, streaks and watching ads | 100 Arcane = $1, plus a payment fee |
| Models | Free models, smaller context | Standard models | Premium models, largest context |
| Can it be bought? | — | No | Yes |
| Expires? | — | Never | Never |
The payment fee depends on where you buy. On the website it is about 10%, so 100 Arcane costs about $1.10. In the Apple and Google stores it is about 34%, so the same 100 Arcane costs about $1.34. The studio says $1 is enough for up to 1,000 messages on the default model with full memory.
Isekai Zero also shows its working. Tap any message and it shows the tokens it used, what share of them was cached, and exactly what it cost you.
Which is cheaper depends on how you play:
- A light player will likely pay less on Isekai Zero, or nothing on either.
- A heavy player on the default model may still pay little on Isekai Zero, if the studio’s figure of up to 1,000 messages for $1 holds for their story.
- A player who wants premium models with a large context should watch the per-message price on Isekai Zero, since a long story sends more text with every turn. Chapters and arcs are the tool for keeping that down.
- A player who never wants to think about cost will prefer AI Dungeon’s flat price, or its free tier.
Our guide to what AI RPGs cost compares the pricing styles across the field.
What Isekai Zero Does That AI Dungeon Does Not
Isekai Zero scores Signature Design — 4.5 against AI Dungeon’s 2. Three things earned it.
It pays its creators, and shows how much. When another player spends paid credits in your storyline, you get a share, paid in money through Wise or XRP. Isekai Zero publishes a monthly leaderboard of creator earnings in US dollars. Read on 24 September 2026, it showed the top creator earning $1,523.29 in August 2026, and tenth place earning $189.31. The studio adds a 30% markup to what each AI response costs it, and the storyline’s creator receives a quarter of that markup. Only paid credits count.
It shows what every message costs. Described above. Most platforms hide this behind a subscription or a daily allowance.
Its memory is a system you can open. Also described above.
AI Dungeon scores 2 on this axis. It is the product the rest of the category grew out of, and we did not find a feature in it today that is only its own.
Which Should You Choose?
Choose Isekai Zero if:
- You want one long story, over many sessions, that remembers what mattered.
- You like starting inside a world with a written cast.
- You want characters with some moral weight.
- You are happy to pay by the message, or to play on free models and earned Mana.
- You write worlds, and want to be paid when other people play them.
Choose AI Dungeon if:
- You want to take a story anywhere, and leave any plot behind without being pulled back.
- You want any genre, from a blank page.
- You want free play with no turn limit and no meter running.
- You prefer a flat monthly price to a per-message one.
One more way to put it. Isekai Zero is better at the story someone wrote for you. AI Dungeon is better at the story nobody wrote.
If Neither One Fits
Both are level and low on Fairness, and neither is a deep rules game. If you want what you own to be earned and a ruleset that pushes back, look at our guide to choosing an AI RPG by what matters to you. For campaigns in particular, see our ranking for long campaigns. For the wider field around AI Dungeon, see AI Dungeon alternatives.
Checklist
- One long story that must remember? Isekai Zero.
- Total freedom, any genre, blank page? AI Dungeon.
- Hate meters? AI Dungeon. Hate subscriptions? Isekai Zero.
- On Isekai Zero, buy Arcane on the website. The store fee is about three times higher.
- On Isekai Zero, use chapters and arcs on a long story to keep the cost of each message down.
- On free AI Dungeon, keep Plot Essentials short. The context is about 3,000 words in total.
- Want dice on Isekai Zero? Pick a storyline with the Dungeon Mind.
Frequently Asked Questions
Is AI Dungeon or Isekai Zero better?
Isekai Zero scores higher on our seven-axis methodology, 3.4 against 2.6 for AI Dungeon. It is ahead on Memory, characters, Mechanical Depth, Longevity and Signature Design. AI Dungeon is ahead on Player Agency, and the two are level on Fairness. If you want one long story that remembers what happened, choose Isekai Zero. If you want complete freedom to take a story anywhere, in any genre, with no charge per message, choose AI Dungeon.
Which has better memory, AI Dungeon or Isekai Zero?
Isekai Zero, 4 against 3 on Memory and Continuity. In our play it forgot only small details that did not matter to the story. It condenses every twenty messages into a chapter and every ten chapters into an arc, and you can open, read and rewrite each summary. AI Dungeon gives you Story Cards, Plot Essentials, an Author’s Note and a Memory Bank, but its context is small on the free tier, about 4,000 tokens on most models, and reaches 32,000 on most models only on the higher paid tiers.
Is Isekai Zero free like AI Dungeon?
Both can be played without paying, in different ways. AI Dungeon’s free tier has no turn limit and nine story models, and its memberships from $14.99 a month buy more models and more context. Isekai Zero has free models, a free currency called Mana that you earn by checking in and watching ads, and a paid currency called Arcane at 100 for $1 plus a payment fee. Isekai Zero does not sell a flat subscription. The studio says $1 is enough for up to 1,000 messages on its default model.
Can I choose my AI model on both?
Yes. AI Dungeon listed nine story models on its free tier and up to twenty-two on its paid tiers on 2 October 2026. Isekai Zero lets you pick from free, standard and premium models, with DeepSeek v4 Flash as the default according to its pricing page, and you can change model in the middle of a story without losing anything.
Which gives the player more freedom?
AI Dungeon, 4 against 3.5 on Player Agency. Neither one writes your character’s actions for you by default. The difference is railroading. An Isekai Zero storyline has a set cast and plot points, and when we walked away from them the story kept bringing them back. AI Dungeon goes wherever you take it.
Do either of them have dice and a character sheet?
Isekai Zero does on some storylines. Those come with a rules referee called the Dungeon Mind, which rolls a d20 on the server and keeps a character sheet with health, conditions and levels. AI Dungeon has no dice built in, though a scenario’s author can add mechanics with scripting. Neither is a deep rules game: Isekai Zero scores 2.5 on Mechanical Depth and AI Dungeon scores 2.
Can creators earn money on Isekai Zero?
Yes. When another player spends paid credits in your storyline, you receive a share, paid out in money through Wise or XRP. Isekai Zero publishes a monthly leaderboard of creator earnings in US dollars. On 24 September 2026 it showed the top creator earning $1,523.29 in August 2026. Only paid credits count, and credits you spend on your own storyline do not.
Both platforms are scored on Arcanum’s seven-axis methodology; the axis values quoted here are the published scores on each platform’s entry as of 8 October 2026. Isekai Zero gave us free Arcane credits for our review; no conditions were attached, and Arcanum is independent and unpaid. AI Dungeon and Isekai Zero are third-party platforms and all names are used nominatively. Arcanum is not affiliated with Latitude, Isekai Zero or ARX Media Sdn Bhd.