Ghelmyon

A deterministic, single-player MUD

A simulated world with persistent state, system-driven mechanics, and generative dialogue layered on top.

What this is

Ghelmyon is a text-based simulation where every action is resolved by game systems.

Combat, inventory, reputation, and time are all mechanically tracked
NPCs have schedules, relationships, and fixed world positions
The world state persists and evolves based on player actions

This is not freeform storytelling.
It is a structured simulation with consistent rules.

Dialogue layer

NPC dialogue is generated from the current world state.

The model receives structured context — who is present, relationships, mood, recent events
It produces conversational flavour and scene description
It does not decide outcomes or modify the world

All gameplay decisions are resolved before any text is generated. The dialogue reflects the state — it does not create it.

System boundaries

Each part of the game has a clear role:

Simulation layer

Stats, combat, inventory, reputation
NPC routines, locations, and relationships
Event resolution and world state updates

Dialogue layer

Describes scenes and interactions
Adapts tone based on context
Adds variation and flavour

The separation is strict. The simulation is always the source of truth.

Try a few commands

Start simple:

you> look you> talk phaedro you> go tavern you> drink ale

Then push the systems:

you> steal bread you> stab wolf high you> flirt bartender

Observe what changes — not just what is said.

System interaction

The game becomes interesting where systems intersect.

Combat affects fatigue and injury
Reputation influences prices and NPC reactions
Social actions can trigger gossip and relationship changes
Time of day changes who you'll find and where
Crime spreads to neighboring towns at dawn

Outcomes are not scripted. They emerge from mechanics interacting over time.

Example

you> steal from aldric [Pickpocketing check: Roll 68 vs 55 — Success] [Stole 12 gold from Aldric] [+1 SP: Pickpocketing (filch)] [Reputation: Merchants —2] [A guard becomes suspicious] Later, someone mentions the incident. Prices increase. The dialogue changes. The outcomes are driven by the underlying systems.

Nothing is scripted.
Nothing is reset.

The world keeps going.

Consistency and safety

Dialogue output is filtered to remain in-world and appropriate
It cannot block or alter gameplay actions
The system continues to function if dialogue generation fails
A fallback mode ensures the game remains playable without live generation

Alpha — demo accounts available

Play Ghelmyon Browse the Wiki

Want the full breakdown?
Mechanics | Beginner Guide | Choose a Class