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Game Master Guide

The Game Master describes things in the world, and narrates what happens in response to player actions. Here are some tips and tricks for running the game.

You can find a one-page GM cheatsheet on the downloads page.

The Guiding Principles

There are three core principles to running a game of Adventure.

  1. Follow the fiction. The story is more important than the rules and mechanics. Let the fictional world guide what happens when players do things.
  2. Portray a fantastic world. Fill the worlds you explore with awe, wonder, mystery, danger, and humanity.
  3. Play to find out what happens. Don’t give your stories predetermined endings. Give players meaningful choices that drive the narrative.

Starting the Game

Start a game of Adventure by describing the fantastic location or tense situation the players find themselves in. Throw them right into the action.

Then ask, “What do you do?”

Example: The Isle of the Kraken

Once every few years, a tiny island mysteriously rises from the depths of the sea for just a few hours. It never appears in the same place twice. Sometimes, it disappears before anyone’s even taken notice.

In the center of the island is a stone monolith, a small tower with a carving of a kraken at the top. It’s rumored that a powerful wizard who lived there thousands of years ago hid a magical conch shell somewhere on the island.

Many an explorer has ventured to the island searching for it. None have returned. Tonight, the island has surfaced again. You’re in a rowboat, headed in the direction it was allegedly seen. Water laps at the low sides of the boat.

Suddenly, you catch sight of it. In the distance, you see the monolith, the carving of the kraken lit brightly by the full moon above.

As you approach the shore, you see a ship moored to a tree, a black flag with two crossed tridents flapping in the gentle breeze. You notice two pirates asleep next to the tree. Foot prints lead into the forest towards the monolith.

What do you do?

Creating a Fantastic World

As a GM, you want create a fantastic and living world for the players to explore.

Identifying a few aspects of your world ahead of time can make it a lot easier to improvise, respond to what your players do, and breathe life into your world.

  • Fantastic Locations. Amazing places that the players can explorer, with a few details and unique features. Imagine a place that’s really big, really old, or really weird.
  • Creatures. What kind of creatures live there? Do they have any features that are unique to their environment?
  • Non-Player Characters (NPCs). Identify a few groups of people who might occupy a location. Are they long-term residents, or just passing through? Do the different groups get along?
  • Dangers. What natural obstacles might players might encounter? Are there any traps that were set to keep trespassers away?
  • Loot. Treasure, magic items, and mundane objects can reveal secrets about the world, drive a quest, or give the players new powers and abilities.
  • Area Effects (optional). Random happenings that might occur in a location. These can bring a sense of whimsy, danger, and life to a fictional world.

These are modular, and designed be dropped into the story whenever appropriate.

Example: Isle of the Kraken


  • A mysterious island that emerges from the sea every few years. A ship moored to a tree, with a black flag featuring two crossed tridents. A tall monolith protruding from the trees. Sleeping pirates and empty rum.
  • Jellyfish Lake. A massive cavern with huge subterranean lake. Jellyfish fill the water, glowing blue/purple. A small island with an obelisk in the middle.
  • Kelp Forest. Narrow paths carved through tall fronds of kelp. A wet floor with scurrying crabs. A clearing featuring a giant clam a large pearl in its mouth.


  • Jellyfish. Glow-in-the-dark, long tentacles.
  • Piranha. Range in size from small as a goldfish to as large as a shark.
  • Turtles. Many species. Some have runes carved into their shells.
  • Giant Seahorse. Domesticated. Can be ridden.
  • Kraken. Roams the caverns protecting its secrets. Has magical abilities.


  • Pirates. Seeking the conch. Just visiting.
  • Crab Tribe. Large sentient crabs. Horde treasure, rob from visitors, and fear the kraken (who eats them).
  • Gnome Cultists. Worship the turtles, ride seahorses, hate the crabs.


  • Flood Room. The floor of the kelp forest is wet, with the occasional fish flopping around. Removing the pearl causes the room to seal and flood.
  • Acid Bubbles. Bubbles float up from a pool of water and pop on the ceiling. Where they pop shows signs of corrosion.
  • Animated Statue. A statue of a mermaid with opal eyes. A sign that reads, “Do NOT touch.” Touching the statues causes it to animate and attack.


  • Seaweed of Speed. When consumed, the person who eats this seaweed is able to run twice as fast as they normally could.
  • Armor of the Leatherback Turtle. Automatically heals one moderate injury at the end of any combat encounter.
  • Merrow Trident. Seems to magically find its mark. User gets advantage on all attack rolls.
  • Random Trinkets. A leather bag filled with smooth pebbles. A jar of black sand. A buoy with a bite taken out of it.

Area Effects

  • The smell of rotting fish wafts into the room, and lasts for one minute.
  • A nearby body of water bubbles as if boiling, then stops.
  • A group of shellfish begin singing in unison.
  • Two toads hop around the corner, engaged in a ritual battle.

World-Building Inspiration

Pull ideas or whole worlds from your favorite books, shows, and movies!

You might explore the post-apocalyptic world of Kipo and the Age of the Wonderbeasts, travel through space as your favorite Star Wars or Star Trek character, or explore the tiny world from the perspective of small mammals like mice or bunnies.

Want a ready-made world to explore? You can use the Adventure rule system with other RPGs. Here are some I recommend.

Story & Mechanics

Your primary role as a GM is translating story elements into mechanics and back again. Here are some tools to help you do that more easily.

Accounting for Difficulty

Under the die roll system, every action has the same probability of succeeding (or not). But some actions are inherently more difficult than others.

In addition to advantage and disadvantage mechanics, you can account for difficulty in complex situations by breaking each step into its own die roll.


A player is trying to run up to a giant, scale his 20-foot high boot, and hit him with a sword. This would involve three separate die rolls.

  1. A roll to sneak up to the giant undetected (or avoid obstacles thrown at you while approaching).
  2. Another roll to scale the boot without falling or getting knocked off.
  3. A third roll to see if the hit with the sword does anything.

Fail Forward

Statistically, failed die rolls will happen about a quarter of the time a player rolls.

Failure should still drive the narrative forward. It’s far more interesting than simply saying, “No, that didn’t work.”


  • The player fails to pick the lock on the chest. It springs a trap, causing the room to lock and start filling with water!
  • The player tries to jump across a cliff and fails the roll. They slam into the cliff wall and fall onto a ledge 20 feet down. They think they’ve escaped the worst of it… until the ledge starts to shift and crack under their weight.

Common Actions & Outcomes

There are a handful of types of player actions that happen frequently in Adventure. Here are some ideas for improvising outcomes for them.

Remember: these are guidelines, not rules!

Cast Spells
When casting a difficult or powerful spell…
  • 9+ The spell works
  • 6-8 It also draws unwelcome attention or goes out-of-control
When making an attack…
  • 9+ Your attack lands
  • 6-8 The enemy also hits you or you get put in a tough spot
Defy Danger
Any time you try to avoid danger or getting hurt…
  • 9+ You succeed
  • 6-8 You stumble, and choose from a worse outcome or tough choice
When you try to defend yourself of a teammate from an attack…
  • 9+ Block the attack
  • 6-8 Lessen the damage, or block all of it but damage your armor or weapon
Understand the World
Whenever you try to study the world around you, a person, or a situation… On a 9+, the GM answers three questions. On a 6-8, they answer one.
  • What happened here recently?
  • What is about to happen?
  • What should I be on the lookout for?
  • What here is useful or valuable to me?
  • Who’s really in control here?
  • What here is not what it appears to be?
Recall Knowledge
Whenever your character tries to recall something that they would know in the story…
  • 9+ The GM will tell you something interesting and useful
  • 6-8 The GM will tell you something interesting only
When you try to persuade or intimidate someone…
  • 9+ They do what you want
  • 6-8 They do what you want, but require something from you first
Last Breath
When a character is dying…
  • 9+ Death allows them to return to the living
  • 6-8 Death requires something in return

Random Tables

One of the most important tools I use in my games is random tables.

The fantastic worlds you create are living, breathing places. Creatures wander around. Items are found, hidden, and lost. Strange and magical things happen.

Random tables can help you generate ideas and surprises as you play.

Encounter Table

The single most important random table I use is the Encounter Table. I roll 1D6 any time players enter a new area to determine what will happen.

In very dangerous areas (like deep into a dungeon), I add +1 to the roll. In safe areas (like a town or village), I subtract -1 from the roll.

1D6 Encounter
0-2 Nothing
3-4 Evidence of Creature/NPC
5 Area Effect
6 Creature/NPC
7 Creature/NPC + Roll Again

Creating Random Tables

I use random tables to determine the loot players find, the creatures and NPCs that are in an area, and area effects that occur.

The amount of options to choose from for any one of these can vary wildly, though, so I use different types of tables depending on the number of choices there are.

  • 1D6. For 6 or fewer options. You can also use this for two or three choices by using roll ranges: 1-3 and 4-6, or 1-2, 3-4, and 5-6.
  • 1D6, then 1D6 again. For 12 to 18 options. Split your options into groups of six. Roll 1D6 for the group, then 1D6 for the option in that group.
  • D66. Gives you 36 options. Roll 2D6 to get a two-digit number (don’t add them together). For example, a 2 and 4 would be 24 (or 42).
  • 1D6, then D66. For more than 36 options. Create two or more groups of 36. Roll 1D6 for the group, then D66 for the option in that group.
  • 2D6. When some options should happen more often. This results in a probability bell curve, with rolls of 6-9 happening most frequently.

Creatures & Non-Player Characters

Creatures and NPCs in your world are likely to be quite varied.

  • They may be friendly allies to the party, enemies, or weird and wondrous creatures.
  • They may be natural friends or enemies with other creatures or NPCs in the area.
  • Their health rules probably differ from player characters (they might be weaker, stronger, or virtually invincible).
  • Focus on the narrative, and what makes sense in the world you’re building.
  • Most creatures will flee a fight if they think they’re going to lose.


  • A friendly gnome, lost in the tunnels for a week, is offered food by the party. To show her gratitude, she leads them to a glowing sword she discovered, wedged firmly into a rock.
  • A swarm of rats rushes at the wizard. He launches a fireball at them, instantly vaporizing a dozen of them.
  • The archer shoots arrow after arrow at the dragon. Each one bounces off its tough scales. The creature doesn’t even seem to notice.
  • The pirate captain drops unconscious after being hit with a warhammer. Sensing the shift in the battle, three of his crew take off running down the tunnel. The remaining pirates lay down their swords in surrender.

Creature & NPC Tables

When a creature or NPC encounter occurs, I like to use a Creature & NPC table recommended by Baron de Ropp from Dungeon Masterpiece.

  1. Pick six creatures or NPCs likely to exist in that region.
  2. For each one, identify a likely behavior and complication.
  3. Put them in a table.

You can either roll once and go with the defaults, or roll three times and mix-and-match behaviors and complications in interesting ways.

Note: if you need help coming up with creatures for a particular area or environment, this random generator from Goblinist can help spark some ideas.

Example: Isle of the Kraken

1D6 Creature/NPC Behavior Complication
1 Animated Statue Alert Injured
2 Turtles Grazing Sick Young
3 Giant Jellyfish Asleep Lost
4 Gnome Cultists Healing Turtles Broken Tools
5 Crab Tribe Patrolling Understaffed
6 Pirates Delving Angry at Boss

If you rolled a 4, you could have Gnome Cultists who are healing turtles but have broken tools.

Or you could roll again. Let’s say you rolled a 1 and a 3. Now they’re on alert (maybe there’s been many crabs in the area), and find themselves lost.


One of the most exciting parts of exploring fantastic locations is finding treasure and magic items that grant characters new abilities.

The most meaningful items are tied to the locations where they’re found, and provide some kind of minor benefit or magical effect. What’s the story behind them? How do they thematically tie into your world?

Players can actively search for loot while exploring, receive it as a gift or reward from an NPC, or buy it or barter for it.

Note: not every item has to be magical, valuable, or powerful. Random junk can be just as fun, and players will often use it unexpected ways.

Examples: Isle of the Kraken

The Isle of the Kraken was home to merfolk wizard who spent his days experimenting on sea creatures and crafting items from their magical properties.

Armor of the Leatherback Turtle
Automatically heals one moderate injury at the end of any combat encounter.
Seaweed of Speed
When consumed, the person who eats this seaweed is able to run twice as fast as they normally could for about an hour.
Ring of Aquatic Beasts
A ring made of abalone. The wearer rubs ring and names an aquatic animal. On a successful roll, they acquire 1-2 traits from that animal.
Random Junk
A bag of sand. A gem that glows in the water. A singing shellfish. A crocodile tooth necklace. A bag filled with snail shells.

Area Effects

Area effects are random happenings that might occur in a location. These can bring a sense of whimsy, danger, and life to a fictional world.

I try to make them relevant to the location itself, the story and history of the world, and the types of creatures and NPCs that live there.

Examples: Isle of the Kraken

  • The smell of rotting fish wafts into the room, and lasts for one minute.
  • A nearby body of water bubbles as if boiling, then stops.
  • A group of shellfish begin singing in unison.
  • Two toads hop around the corner, engaged in a ritual battle.
  • A strange aura passes over the room. Seawood begins growing anywhere visible hair does.
  • A rat on a leash wanders through the room, with no owner in site.

Traps & Obstacles

Signal serious dangers to players. Don’t surprise them with danger they can’t avoid. Put traps in plain sight.

The more dangerous it is, the more obvious it should be. Give players opportunities to solve problems and interact with the world. Reward creativity and problem-solving.

This video from Ben Milton is a great primer.

Examples: Isle of the Kraken

Flood Room
The floor of the kelp forest is wet, with the occasional fish flopping around. Heavy gates are visible along all entrances. There are visible holes along the walls or floor. Removing the pearl causes the room to seal and flood. A waterlogged explorer is discovered next to the pearl.
Acid Bubbles
Bubbles float up from a pool of water and pop on the ceiling. Where they pop shows signs of corrosion. When they pop, a foul smell is emitted. Getting to the next room requires players to walk across a narrow bridge over the pool.
Animated Statue
A statue of a mermaid with opal eyes and a trident. The body of an explorer, with three puncture wounds, found a few feet away. A sign that reads, “Do NOT touch.” Touching the statues causes it to animate and attack.

Using Maps

You can play Adventure entirely in your imagination, but a map can also help make the world feel more real for some players.

Dyson Logos is a fantasy cartographer who has released over a thousand free maps for commercial use on his website.

I often pick 1-3 maps from Dyson Logos’ site, and write down 1-3 unique features of each room or place on the map.

Sometimes I show players a blank version of the map. Other times, I’ll sketch the map live on a Paizo Flip Mat. And sometimes, I skip the map altogether and we just use our imagination.

Maps (and your descriptions of each room) don’t need to be really detailed. In fact, it often takes away from the game if they’re too detailed or realistic. They’re a tool to spark your imagination while playing.

Duration and Complexity

Games of Adventure can take as little as 30 minutes or last several hours.

As the Game Master, you have a lot of control over the length and complexity of each game. You can add or remove creatures, reveal or discard secrets, adjust the HP of creatures, and save the day with NPCs.

You can also spread an adventure over several sessions, stopping after an encounter, and picking things back up another time.

Playing Online

With a global pandemic, a lot of RPG games have moved online.

There are a lot of tools to help facilitate this, but my personal favorite combination is is Owlbear Rodeo and Zoom or Google Meet. I let players roll their own physical dice instead of trying to do something digital.

Nate from WASD20 has a great video on how to use Owlbear Rodeo.

Additional Resources