As the Game Master, you wear many hats: storyteller, entertainer, judge, inventor, and player. You're in charge of creating an entire world for your friends to explore, and you fill the shoes of every nonplayer character they interact with. While this can be a lot of work, it can also be deeply rewarding. As the GM, you're the ultimate arbiter of everything in your game—you can change setting details or even fundamental rules of the game as you see fit—but below are some systems and tips to help make your GMing experience fun and smooth. 

Building an Adventure

How much work you put into preparing your adventure is up to you. The easiest approach is to simply modify or run a published adventure (see the sidebar on page 392). While published adventures are usually quite intricate, with beautiful maps and interwoven storylines, don't let that intimidate you. If you're the only one running your adventure, you can easily get by with just a few notes, such as an outline of the plot, a map or two of main adventure sites, and a few stat blocks or notes for the creatures you plan to use as enemies. Some people run entirely off the cuff, while others write everything down. Whatever lets you relax and have fun at the table is the right choice. 

If you decide to write everything out, however, remember that an adventure is not a novel. The other players control the main characters, and you should leave room for them to shape the action. If the characters steal a shuttle and head down to the planet when you expected them to try and capture the ship's bridge, don't despair! Just grab the Starfinder Alien Archive, flip it open, and tell them what weird creatures—perhaps lurking within some strange alien ruins inscribed with mystical signs—they find when they land. Maybe you can still bring the story back around to your original idea after this side quest, but adapting your story in response to player action is what makes a group storytelling game like Starfinder exciting and surprising for the GM as well as the players!

The following pages contain some key issues you should consider before sitting down to run a game, as well as elements that, if prepared in advance, can save you a lot of time and frustration at the table.

Stat Blocks

Stat blocks are one of the most complex parts of the game, but also the most useful. They tell you everything you need to know about a creature or character's abilities in a fight, much like a condensed version of a character sheet.

How you use stat blocks is up to you. Some Game Masters like to create custom stat blocks for most of the allies and enemies encountered during an adventure, some like to create them only for the biggest and baddest enemy characters, and others are perfectly happy to repurpose statistics from other adventures or books like the Alien Archive. Some GMs don't even bother with full stat blocks and just write down a few key statistics—Armor Classes, attacks and damage, Hit Points, and saving throws—and ignore the rest unless it becomes important.

All of these approaches are valid, but in general, the ways you expect your party to interact with a character determine what you need. If your PCs go to a nonplayer character (NPC) for research assistance before their next mission, then you probably need to know only a few skill values, whereas you'll probably need to know all the combat statistics for the Free Captain pirate they battle in the adventure's climax. Also remember that in addition to using published characters and creatures as written, you can simply “reskin” those creatures.

If you use the statistics for a haan but describe fins and jets instead of claws and balloons, a cold spray instead of firespray, and a swim speed instead of a fly speed, congratulations—you've created a brand new alien, and your players will never know the difference!

Level Equivalent for Monsters and NPCs

Many abilities and effects are based on a creature's level. Unlike player characters, however, monsters and NPCs don't have levels. Instead, the CR of a monster or NPC functions as its level for any ability or effect based on level.