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Improv Versus Prep

by Mike on 27 October 2025

How often do you improvise NPCs during your game?

When you do, what material helps you improvise them?

What's missing from these improvised NPCs? Do you or your players notice?

Given the answers to these questions, what material do you need next time to help you improvise NPCs in the future?

I think the questions above narrow down the necessity of what we prepare and what we need to improvise parts of our games. I'm focusing on NPCs but this could be locations, scenes, combat encounters, treasure, or anything else we typically use to run games.

GMs often improvise NPCs. A list of random names is a big staple in the kits of many GMs so GMs can quickly create NPCs out of thin air. For my own games, I don't need much more than a name. I tend to fall into the NPC, improvising their behavior, mannerisms, and other aspects as we play. But I suck at names – both coming up with them and remembering them.

These experiences tells me something. If I find myself able to improvise NPCs with just a name during a game, I probably don't need more information than a name when I prep an NPC.

What we need to prepare and what we can improvise during the game is different for each of us, but I think we can go through the exercise at the beginning of this article to figure it out.

Look at what really happens during your game and then go back to figure out what you actually need next time. It might turn out that 500 words of background, history, mannerisms, physical traits, and prepared statements for particular queries or situations isn't really needed if you can just drop behind the eyes of an NPC and wing it.

Recently I ran a game in which my characters delved into tunnels connecting sub-basements, cisterns, and sewer systems of a town. I wasn't ready for the delve but I had some maps in my GM kit – enough to run a few scenes in there. I rolled up some monsters and had some general room descriptions. I didn't have the sewer maps from The Lazy DM's Workbook, which would have helped, but the material I did have worked well enough. A perceptive player might have noticed me flipping around a lot in my book and been suspicious but no one seemed to mind.

Can I get away with that little prep? Probably not. I prefer more prep for locations like this dungeon – something to make chambers interesting and specific to the circumstances. But I don't need much more than this. I can write down a list of possible rooms without necessarily marking them on a map and do just fine.

General purpose random monster lists often work well enough – along with rolling dice for attitude, behavior, and distance. But customized lists of monsters for this particular situation and location would have worked better.

I know I can't come up with great secrets and clues to drop in my game on the fly. I like to give secrets more thought than I can whip up at a busy table. So secrets are something I definitely prepare ahead of time. Same with strong starts, lists of scenes, and other aspects of the eight steps from Return of the Lazy Dungeon Master.

I always find it useful to walk through the eight steps, even if I don't write down every step. The amount of material I need for each step might be less based on what I find myself actually using at the table.

Look at what you use at your table. What do you use of your prep? What do you improvise? Use your experiences at every session to change your prep and help you run the next one.

More Sly Flourish Stuff

Last week I was at Gamehole Con in Madison, Wisconsin. There I was on a handful of panels, two of which I recorded and posted to the Lazy RPG Talk Show (also available as a podcast). You can listen to them here:

RPG Tips

Each week I think about what I learned in my last RPG session and write them up as RPG tips. Here are this week's tips:

Write down place names to help players keep track of where they’ve been and where they’re going.
Give players a sense of scale of the huge locations they explore.
Set up challenges and let players decide how to navigate them. Avoid pointlessly restrictive sets of options.
Run a mix of easy and hard fights.
Let the world determine the difficulty of an encounter.
Ask players how their characters search for and disarm traps. Don’t just depend on the dice.
Use a mix of battle maps — small diagrams, gridded drawings, pre-printed maps, 3d terrain. Use whatever you have.

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