Game Master is the feature that separates Arma Reforger from every other military shooter. One player (or a small team) gets a top-down view of the map and can spawn, move, and control AI units, place objectives, trigger events, and essentially DM a military operation in real time while other players experience it from the ground.
Running a Game Master session on a dedicated server means the GM does not need to host the game on their own machine, players can join independently, and the server stays up between sessions. This is how communities run persistent campaigns and scheduled operations.
Enabling Game Master on Your Server
Game Master is a scenario type, not a setting you toggle. Your server needs to load a Game Master scenario instead of a standard Conflict or Capture & Hold scenario. A server runs one scenario at a time, so Game Master next to Conflict means a second server instance.
Server Configuration
In your server.json (the main Arma Reforger server config), the scenario is set like this:
{
"game": {
"scenarioId": "{59AD59368755F41A}Missions/21_GM_Eden.conf",
"gameProperties": {
"serverMaxViewDistance": 2500,
"serverMinGrassDistance": 50,
"networkViewDistance": 1000,
"disableThirdPerson": false,
"fastValidation": true
},
"maxPlayers": 64
}
}
The scenarioId for Game Master on Everon is {59AD59368755F41A}Missions/21_GM_Eden.conf, and for Arland it is {2BBBE828037C6F4B}Missions/22_GM_Arland.conf. Both are in the official scenario list on Bohemia's Server Config page. Update 1.6 added Game Master Kolguyev as well; start the server with the -listScenarios parameter and the log shows its path. A custom map from the Workshop only has a Game Master scenario if its author made one, and the map's Workshop page lists the Scenario ID under its Scenarios tab.
Who Can Be Game Master
By default, any player who connects to a Game Master scenario can request the GM role. On a public server, this is a problem. You probably want to restrict it.
The Game Master role is controlled through server admin permissions. Add trusted players to your admin list in the server config:
{
"game": {
"passwordAdmin": "changeme",
"admins": [
"IDENTITY_ID_OR_STEAMID64"
]
}
}
The admins list sits inside the game block and takes identity IDs or SteamIDs as plain strings. Players on it can type #login in the chat without the password; anyone else needs the passwordAdmin value, so keep it private. Players with admin permissions can access Game Master tools. Regular players experience the session as normal infantry.
Game Master Interface
When a player with GM permissions joins and activates Game Master mode, they get:
The Overview
A top-down map view of the entire play area. You can zoom from satellite level down to individual building level. Player positions show as icons with their names, directional facing, and current state (alive, wounded, in vehicle).
Entity Palette
The left panel lists every spawnable entity in the game:
- Infantry units: individual soldiers of every faction, class, and loadout
- Vehicles: cars, trucks, APCs, IFVs, helicopters
- Structures: buildings, fortifications, sandbag walls, barriers
- Props: crates, fuel stations, medical supplies, ammunition
- AI groups: pre-configured squads with proper composition
Click an entity and click on the map to place it. For AI units, they will immediately begin behavior based on their type (patrol, defend, attack).
AI Commands
This is where Game Master gets interesting. You can:
Select AI units individually or as groups
Give waypoints: click to create a movement path. AI will follow it, engaging threats along the way or avoiding them based on their rules of engagement.
Set behavior: defend a position, patrol an area, attack a target, retreat, search a building
Control a unit directly: take over any AI soldier and play as them temporarily. This lets the GM create "boss" encounters or scripted moments.
Adjust skill level: make AI deadly accurate or intentionally poor. This lets you scale difficulty for the player group.
Objective System
Game Master can create objectives visible to all players:
- Attack objectives (red markers)
- Defend objectives (blue markers)
- Move/recon objectives (yellow markers)
- Custom tasks with descriptions
These show on players' maps and HUDs, giving structure to the operation without the GM needing to explain everything over voice.
Running a Good Game Master Session
Preparation
The best GM sessions are not improvised. Before players join:
- Plan the operation arc: opening situation, two or three objectives that flow into each other, a climax, and an extraction
- Pre-place static elements: buildings, fortifications, initial enemy positions. Spawning things during play is fine, but having the world populated before players arrive sets the tone immediately
- Set the weather and time: match the atmosphere to the operation. Night operations feel completely different from daytime. Rain reduces visibility and changes the audio landscape
- Write a brief: a few sentences of context that you can read to players at mission start. "You are a rifle squad tasked with clearing..." gives players purpose
During the Session
Stay ahead of the players. The GM should be setting up the next objective area while players are still working on the current one. If players arrive at a location and it is empty because you had not placed enemies yet, the immersion breaks.
React to player decisions. The plan is a starting point, not a script. If players decide to flank left instead of approaching from the front, adjust the enemy positions to create an interesting encounter from that direction. The players should feel like the world is reacting to their choices, even when it is you making it happen.
Use AI reinforcements instead of respawns. When AI is killed, do not immediately spawn replacements in the same spot. Bring in reinforcements from a logical direction. A truck pulling up with fresh troops is more immersive than enemies materializing.
Control the pacing. After an intense firefight, give players a quiet moment to regroup, treat wounds, and discuss. Then escalate again. The rhythm of tension and relief is what makes a session memorable.
Communicate sparingly. The GM can broadcast text messages and use voice channels, but less is more. Let the situation communicate. If players need to fall back, send a flanking enemy group rather than telling them to retreat.
Common Mistakes
Spawning too many enemies at once. A squad of 8 AI is a firefight. A platoon of 30 is a massacre (of the players or the server tick rate). Scale to your player count.
Over-scripting. If you have planned every movement and reaction, you are making a movie, not running a game. Leave room for player agency.
Ignoring server performance. Every AI unit costs server resources. A 64-player server with 200 spawned AI will struggle. Keep total AI count reasonable: a good rule of thumb is no more than 3 to 4 AI per player, active at any time.
Not testing the scenario first. Join your own server alone, place your initial setup, walk through it from a player perspective. Fix the things that look wrong from the ground.
Server Performance for Game Master
Game Master sessions are the most demanding workload for an Arma Reforger server because you are running both player connections and AI simulation.
| Players | Max recommended AI | RAM | CPU notes |
|---|---|---|---|
| 8 to 16 | 40 to 60 AI | 8 GB | Single-thread performance matters |
| 16 to 32 | 60 to 100 AI | 12 GB | Fast clock speed, NVMe storage |
| 32 to 64 | 80 to 150 AI | 16 GB | High single-thread speed matters most |
The AI simulation is the bottleneck. Each AI unit runs pathfinding, threat detection, and behavior trees every tick. Urban environments are worse than open terrain because pathfinding through buildings is more complex.
Our Arma Reforger server hosting runs in nine regions: the Netherlands, Germany, Poland, Canada, USA (California), USA (Virginia), Singapore, India and Australia. Plans go from 2 GB (Private) to 12 GB (Colonel) of RAM. Treat the table above as a rough guide for any Reforger server, not as a rating of our plans, and for a 32 to 64 player event with heavy AI, ask us in live chat before you order. NVMe storage keeps the terrain streaming smooth, which matters in Game Master because the GM often forces the server to load areas ahead of players.
Workshop Mods for Game Master
Several Workshop mods extend Game Master functionality:
Extra entity packs: community-made factions, vehicles, and props that expand your spawnable palette.
Scenario frameworks: pre-built mission templates with triggers, scoring, and extraction mechanics that save the GM from building everything from scratch.
Enhanced AI modules: mods that add patrol routes, garrison behavior, and ambient civilian populations without manual placement.
Add them to the mods list inside the game block of server.json, and the server downloads them when it starts:
{
"game": {
"mods": [
{
"modId": "MOD_ID_HERE",
"name": "Mod Name"
}
]
}
}
Players do not need to subscribe to these mods first. Bohemia's Server Config page says the mods in this list are downloaded and activated automatically when a player joins.
FAQ
Can multiple players be Game Master simultaneously? Yes. Multiple admins can open Game Master mode on the same server. This is useful for large operations where one GM handles the north sector and another handles the south.
Can I save a Game Master scenario and reload it? Partially. The scenario state (placed entities, objectives) can be saved through the server, but AI states and dynamic elements may not persist perfectly across restarts. For persistent campaigns, communities often rebuild the starting state at the beginning of each session.
Does Game Master work with Conflict mode? Not directly. Game Master is its own scenario type. However, some community mods combine Game Master tools with Conflict mechanics, allowing a GM to influence a running Conflict match.
What is the difference between Game Master and the Workbench editor? Workbench is the offline mission editor for creating pre-built scenarios with scripted events. Game Master is real-time, reactive, and happens during play. Workbench creates the product; Game Master creates the experience.
Related guides: for initial server setup, see Arma Reforger dedicated server setup guide. For extending your server with Workshop content, read best Arma Reforger mods and scenarios.
How much bandwidth does a Game Master session use? More than a standard match because the GM spawns and despawns entities frequently, each generating network traffic. Budget 10 to 15 Mbps for a 32-player session with active GM spawning. On a 100 Mbps server connection this is not a concern.