After a particularly brilliant session, I was walking home with our friend group’s GM. Although he had run another session just three days earlier, this last session was a fantastic, fully fleshed out adventure. I imagined him spending late night after night tinkering in his DM workshop, I asked if my DM was okay. “I just want to make sure you aren’t killing yourself over these games,” I blurted out.

Our DM laughed in response. “Nah, don’t worry about it,” he said, “I just use modular NPCs, it makes it a lot easier.” Immediately, I asked him what he meant. He started explaining the world of modular NPCs. My whole RPG world shifted.

You see, outside of very extreme circumstances, a fun and exciting NPC is agnostic of the world in which you’re playing. That means that as a DM, you can re-use the NPCs you’ve built for prior parties. Each new group of players can experience an expanding menagerie of characters with their own personalities, motivations, and quirks. Over time, this cast grows and grows, and the amount of work you need to do for each campaign decreases.

Designing your NPCs for re-use doesn’t just make it easier to set up sessions, it also makes those sessions higher quality. Just think of how we build things in our lives. If you needed to build some place to sleep for only one night, you’d probably throw together a lean-to out of sticks and wood. It’ll keep you safer for the night, but in a day or two it’ll fall down. If you needed to build a place to sleep for 10 years, you’d be calling in a construction company to make you a whole house. That’s the difference between designing one-time use NPCs and modular NPCs. For a single use, you might throw something together. When you’re designing a character to be used over and over again, take your time to ensure you’re doing it right.

Finally, modular NPCs can be shared. If you make some interesting modular NPCs, you can easily send them to other DMs. Start making modular NPCs, and soon, you might become the most popular DM on your side of the Rocky Mountains.

Here’s some advice on how to construct modular NPCs that can make your life easier as you go.

Start with their personality The defining aspect of an engaging NPC is their personality. Thankfully, a personality is also the most evergreen characteristic, you’ll never need to change it depending on your universe. I’d recommend defining an NPC’s personality by separating out overt traits and subtle traits. Try to pick 2-3 of each. Overt personality traits are things that your players might notice right away. It may be an abrasiveness that causes the NPC to pick fights, or a kind heart you might highlight with a gentle act. Subtle traits are things that you should use to guide how the NPC acts but shouldn’t be obvious. For example, your NPC might have a subtle bias against religion. They don’t bring it up, but whenever the party goes into a church, the NPC makes some excuse not to join. Next, develop their motivations. Motivations are the next big thing to nail down. Because these NPCs need to work across many settings, try not to have the motivation be too specific. The motivation “Kill King Edward” isn’t going to be helpful if King Edward is only in one campaign. Instead, try to draw general motivations out of their personality. If one of their traits is that they love money, their motivation could be getting rich. Then, depending on the universe you’ve set them in, you can determine what the particulars are. I’d recommend choosing a few motivations and setting relative priority levels for them. Try to represent your NPCs with the complexity that real people exhibit. Normally, our motivations are constantly contrasting with each other. Additionally, the motivations we say we care about don’t always align with what we actually care about. We may not even mean to deceive people; we just may not understand ourselves well enough to articulate our desires. Keep this in mind when building out your NPCs motivations. Figure out what they look like. Many of the greatest fiction authors talk about how if you can’t picture a scene, you might as well not be reading it. The same is true for building characters. Write a description of your NPC that makes them easier for all of your players to picture. Once again, try to avoid specific information that might change from setting to setting. Instead, create memorable details that can help with visualization but don’t change from setting to setting. Are they well or poorly dressed? Do they walk with confidence or shame? Are they shaven or unkempt? Do they have any odd visual quirks like scars or tattoos? Create a description that allows you to have a clear picture of what they look like. Write it down. If you have the time, come back to it two weeks later and read it again. Do you still have a clear picture? If not, add more.

Finally, a few things to be careful about:

Race If you’re the DM who changes races around frequently or moves from system to system, you can’t take the existence of a race for granted. Instead of specifying an NPC is an orc, take note that that NPC is strong and martial, and use that to inform the race you assign him in any setting. Stat blocks If you change systems frequently, try not to set specific stat lines. Instead, write a few skill sets your NPC is notably good or bad at compared to the system’s standard. Political or religious alignments Specific names here will almost constantly change. Instead of saying they support Queen Aliza, think about what traits make them support that character. Then, write down their more general preferences or beliefs, e.g. “Having faith in the government, they prefer patriarchal and authoritarian factions.

These are just some of my initial thoughts when it comes to modular characters. Do you design modular characters yourself? How do you think about creating them? What are your personal do’s and don’ts?