A memory-first AI RPG built on Maelstrom, a world-state engine that tracks what's currently true instead of searching the chat log.

MythEngyn is an open-beta AI RPG platform that leads with the thing most platforms treat as a feature bullet: memory. Its world-state engine, which the developer calls Maelstrom, tracks the state of the world rather than indexing the transcript — the stated distinction being that search will happily hand back something that stopped being true nine sessions ago, because a search index has no concept of which of two contradictory facts is current. That’s the same problem we break down in why AI campaigns fall apart at turn 50, and the same wager RoleForge makes from a different direction.

Across 24 hours in Narrative Mode — the freeform, choose-your-own-adventure side of the platform — recall was the most stable we’ve tested this early, with one minor miss and no hallucinations. Narrative Mode is also unrestricted in tone: it doesn’t clamp down when a scene gets gritty, and it generally lets you go where you want rather than steering you back.

MythEngyn is built by Mutiny Labs, a bootstrapped two-person studio formed in August 2025 — an engineer and a tabletop designer, no outside investment. The platform ships four modes on one engine (Dungeon Master, Narrative Chat, Interactive Novel, Character Chat), and per founder Eric the beta label is now tied to a single component: the data-driven rules engine, which he says already runs four rule systems from pure data definitions. 1.0 is targeted for November 2026, gated on monster-side mechanical parity and the positioning layer going live. He also puts the platform’s longest continuous campaign at 4,288 turns, and clarifies that “infinite memory” means unbounded retention rather than an infinite context window. See our full interview for the twelve answers in full.

Two gaps are still open. Presentation is thin — no character artwork while you talk, you open a menu to see a face — which is the inverse of Craft’s bet on visual-novel staging. And the AI gives you very little pushback; NPC traits that should hold don’t yet, which the developer confirms is active work. The platform’s crunchier “full rules” mode is still being rebuilt and we haven’t judged it.

Pricing

Plan	Cost	Limits & Features
Solo Adventurer	$25/month, 7-day free trial	Unlimited AI conversations, infinite memory persistence, 150 AI portrait generations/month, unlimited campaigns and characters, custom modules
Party Leader	$35/month, 7-day free trial	Everything in Solo, host multiplayer campaigns, up to 5 party members free, shared campaign world, 300 AI portrait generations/month

Both tiers are marked “Coming Soon” on MythEngyn’s pricing page at time of writing — the beta itself is open to anyone. There’s no free tier announced, only the 7-day trial. See MythEngyn’s pricing page for current rates.

We haven’t rated MythEngyn. See our first look for the fuller take on those 24 hours, including what the developer told us about building a referee the AI can’t overrule, and our interview with founder Eric for the architecture underneath it — a full rated review follows once it leaves beta.