Introduction
What Is The Western Horizon?
The Western Horizon is a design philosophy for running West Marches campaigns where players drive the story through their goals, the GM generates content responsively, and the world is built collaboratively.
Unlike traditional West Marches (where the GM pre-builds an entire world before play), WH generates content when players declare where they’re going and why. Unlike traditional campaigns (where the GM plans storylines), WH lets stories emerge from player goals colliding with faction goals.
The Core Insight
If players bring goals and factions pursue goals, the GM doesn’t need to author storylines. Create obstacles to player goals, let factions advance their own agendas, and story emerges naturally from the collision.
Who Is This For?
The Western Horizon is for GMs who want to run West Marches campaigns but:
- Don’t want heroic prep burdens — Generating an entire world upfront is exhausting
- Want player agency to be real — Not just “which hook do you bite?”
- Value emergent stories — Surprises for the GM too, not executed plans
- Want sustainable long-term play — Campaigns that grow organically without GM burnout
- Enjoy collaborative worldbuilding — The world belongs to everyone at the table
You don’t need to be running a West Marches campaign to use these principles — goal-driven, responsive, collaborative play works in any campaign structure.
New to West Marches?
West Marches is a campaign style invented by Ben Robbins featuring an open table with variable player roster, player-organized sessions, a persistent shared world, and a Guild structure where adventurers gather between expeditions.
See Further Reading for essential West Marches reading.
How to Use This Document
Part 1 — The System
| Section | When to Read | What You’ll Find |
|---|---|---|
| Core Philosophy | First — understand the “why” | Five pillars, GM role, expedition structure |
| People | When generating NPCs | Residents, rivals, quick NPC procedures |
| Settlements | When founding towns | Settlement generation, districts, history |
| Factions | When building power structures | Paradigms, goals, clocks, seat of power |
| Geography | When players explore | Hex map, travel, complications |
| Lore | When seeding discoveries | Discovery pool, delivery mechanisms |
| Quests | When prepping sessions | Quest prep, dungeons, five room structure |
Part 2 — The Play
| Section | When to Read | What You’ll Find |
|---|---|---|
| Session Zero | Before campaign start | Palette, Guild charter, starting era, player goals |
| Sessions | During and after play | Adjudication, recording, post-session procedures |
| Wiki | Ongoing maintenance | Guild Archive structure and workflow |
| Appendices | Reference | Tables, checklists, source credits |
Start Here
First time reading? Read Core Philosophy completely, then jump to whichever section matches your current need. Each section is designed to stand alone.
What You’ll Need
- A TTRPG system — WH is system-agnostic, though examples use D&D 5E terminology
- Players — West Marches works best with a larger pool (8-12+) but can run with fewer
- A communication platform — Discord or similar for between-session coordination
- A wiki or shared notes — Obsidian recommended
- Time between sessions — WH assumes days or weeks between sessions for prep
Optional but recommended: The worldbuilding games in Proven Solutions, session recording tools, virtual tabletop.
This Is Not a Complete System
WH provides philosophy and procedures for campaign structure. It doesn’t replace your TTRPG rules or the worldbuilding games it draws from — you’ll need those source books for full procedures.
Terminology
- GM — Game Master, Dungeon Master, Referee, Facilitator
- PC — Player Character
- Guild — The central settlement/organization where adventurers gather
- Expedition — A single session’s adventure arc (declaration → execution → return)
- Faction — Any organized group with goals
- Canon — Established world facts all players can reference
- Generation — The process of creating new content