I recently ran my first Cortex Prime session. In the video above, I go over how I created my setting, prepared for the session, and debrief on how it went.

What attracted me to Cortex Prime?

In its 2017 Kickstarter, Cortex Prime described itself as a “Multi-Genre Modular Roleplaying Game”. It’s a new system, based on the rule set from prior Cortex games, such as Marvel Heroic, Leverage, Supernatural, Smallville, Firefly, and others.

Cortex Prime seems great for realizing my own homebrew setting ideas. It provides a good middle ground between using an existing system and building a custom system completely from scratch. As a modular toolkit, it provides rules and guidance for trait sets and mods, which you can then mix & match to realize the desired mechanics and vibe for your own game.

I want to call out the elegant Cortex Prime Website as well. Cortex Prime buyers get access to the full searchable text of the book on the website, perfectly formatted for reading either on a desktop or a mobile device. This feels like a superior alternative to PDFs - frankly, all games should have something like this!

Many people might put Cortex Prime into a similar bucket as generic systems like Savage Worlds or Fate. I’ve run both of those systems as well. They’re great games in their own right, but there are some fundamental differences between generic systems and toolkits like Cortex Prime.

An advantage of generic game systems is that they’re much easier to get to the table. While you may need to do a bit of tuning for a homebrew setting, the rules are mostly fixed. And once you’ve used them with one setting, it’s pretty easy to use them again with another setting. The flip side of that is that generic systems tend to feel mostly the same, regardless of setting. E.g. Savage Worlds does pulp adventures amazingly well, but it’s hard to take the pulp out of the system.

In contrast, Cortex Prime requires a fair amount of upfront work for each individual setting you want to run. But as a result, each game will feel very different, depending on the mods and trait sets you chose to use.

There isn’t even a standard way to create Cortex Prime characters. Depending on the game, you might provide archetypes as quick and easy starting points, create characters completely from scratch by distributing trait values based on rules you provide, or use the highly collaborative pathways method to create your setting, characters, and their relationships as a group.

Getting it to the table

This was quite different from my regular approach that I outlined in recent post about How I evaluate and learn new RPGs (video).

This was one of those Kickstarters that delivered several years after it was originally planned. Instead of 1 year, it took 3.5 years… I was a bit lukewarm on it at first after it delivered, but it still managed to pique my interest once I started reading the book. I quickly realized that there was something super elegant about the core mechanic, and the overall toolkit-like premise really resonated with me.

But it also meant that I couldn’t simply read it once or twice and then run it. I first had to figure out a setting, and come up with the right trait sets and mods. And that was difficult because of my lack of experience with the system, since I had never played any of the previous Cortex games. And frankly, the book didn’t make it easy to understand when I might want to use a certain mod.

I ended up putting it aside and picking it back up a few times over the course of almost 2 years. I spent a ton of time on the Discord, Reddit, and other places. The Discord server in particular was very helpful. Cam himself often chimes in, and many other experienced players and Cortex game designers as well.

I also got into 2 one-shots to experience at least the player side of Cortex Prime. I could have run one of the example settings that came with the book, but none of them really resonated with me.

Another thing that made it harder to learn is that Cortex Prime has a relatively small online presence. I haven’t found significant forums or user groups, aside from the Discord and Subreddit mentioned above.

Since I am a bit of a collector, I also bought a bunch of older Cortex games. This highlights another challenge: These games were all based on licenses, all of which had expired - so the books were out of print. But I still managed to track down copies of the books I cared about. Flipping through these games helped me better understand some of the rules, as well as providing inspiration for handling certain things (such as ships).

As a side note: I’m generally not a fan of licensed settings, and wish that Cortex leaned more into their own custom settings instead. The only official Cortex Prime game is Tales of Xadia, which is also licensed, based on a TV show. Why don’t I like licensed settings? For one thing, as mentioned above, licenses eventually expire, which leads to orphaned games. But I also tend to be overwhelmed by the lore. While I love the vibe of movies, TV shows, or books, I’m not good at remembering the details, and always worry that I don’t manage to do it justice, especially if my players are well versed in the lore. So I prefer settings that perhaps borrow the vibe of those properties, but not the actual lore.

My Game: Zombies of the Caribbean

Once I had a high level grasp on the system, I had to decide on a setting and start putting together my hack.

I wanted to run a pirate themed game where those at sea are the only people that have escaped the zombie apocalypse. I’m tentatively calling it “Zombies of the Caribbean”. You can see my custom character sheet below. The sheet is mostly filled in (except for name and description), and represents what a Swashbuckler type character might look like:

Character Sheet

Trait Sets

Cortex has a notion of trait sets, which can be Attributes, Skills, or even things like Values or Relationships, depending on what your game is about. Traits are rated in die sizes, anywhere from d4 to d12. Whenever you make a die roll, you assemble a dice pool by taking one die from each of the main Trait Sets (typically 3), and any other traits that might apply to the situation.

I tried to flavor the names of my traits according to the pirate genre:

  • Attributes: Daring, Flair, Savvy, Vigor
    • Those are about how your character behaves
  • Roles: Carpenter, Commander, Fighter, Sailor, Surgeon
    • You can think of these kind of like skills, but broader
    • And these are not mutually exclusive. E.g. our Swashbuckler above is a great fighter (rated at d10), but their d8 Commander role would mean that they’re also good at getting people to listen to them
  • Distinctions
    • With distinctions, you generally want them to be able to work either in your favor, or occasionally against you (e.g. there’s a Hinder mechanic that allows players to decide that their distinction should act against them on a particular roll, and in return they get a Plot Point)
    • In my game, I chose to make one of the Distinctions about their Approach or Attitude, one about their Pirate Life, and one about a Quirk
      • In case of our Swashbuckler, you see that they are a Dashing Swashbuckler
      • It looks like they are dreaming of having their own ship one day
      • And with their quirk, it looks they can talk themselves out of trouble, but also get themselves into trouble just as often


SFX are essentially advantages that players can unlock over time. I went with pre-written SFX to keep it simple (similar to Hammerheads), although I would let players swap these out further down the line in a longer campaign. Some of these SFX allow players to spend a Plot Point in order to improve their dice rolls; others allow them to create assets or even gain Plot Points by leaning into their quirk (sort of like a self-compel in Fate).

Stress and Trauma

Stress itself is a mod, although a very common one. It either completely replaces or coexists with the default Complications mechanic, and gives you a stress track that you might know from various other games.

I considered the “Shaken and Stricken” mod, which applies stress directly to attributes. But I dismissed this, as it creates an intense death spiral, and I wanted a more pulpy feel for my setting.

Instead, I went with Trauma as a good middle ground. Trauma represents lasting consequences that characters need to recover from over time. It can provide fodder for entire improv sessions, but without completely crippling the character’s actions.

This is a good example of the kind of fine tuning you can achieve with Cortex Prime, compared to generic systems.

I also borrowed the simplified stress rule from Tales of Xadia. Cortex Prime has a slightly weird special case when Stress drops to d4. In fact, there’s lots of discussion about this on the Cortex Prime Discord. Even Cam admits that this rule is a bit awkward, so he simplified it for Tales of Xadia, and I think it works well in my setting as well.


What’s a pirate game without pirate ships? In my game, ships are modeled similar to characters. You can see the ship sheet below:

Ship Sheet

Just like characters, ships have Attributes, Stress/Trauma, Distinctions, Signature Assets, and SFX. Unlike characters, they are missing Roles. I used a mix of vehicle rules from the Cortex Prime book, with some inspiration from previous Cortex books. In particular, in Firefly, spaceships have attributes and distinctions, but crew members use their own Skills when operating the spaceship. So I’m doing the same here, with characters using their own Role trait.

Tests & Contests vs. Action-based Resolution

I fretted over this a lot, and still kind of do. This is something that Cortex Prime doesn’t handle well, in my opinion. The general idea seems to pick one approach and stick with it. But I really like the elegance of Tests and Contests for most things, yet want to be able to handle certain encounters by taking turns more dramatically. Action-based Resolution does that, but it’s different enough from Tests/Contests that it feels like it would be awkward to spring both approaches on players, especially those themselves new to Cortex. I might still use Action-based Resolution in the future, but I decided to mostly just use Tests, and stole Challenges from Tales of Xadia.


In addition to Tests and Contests from the core Cortex Prime book, Tales of Xadia adds a third type of conflict mechanic: Challenges. In my opinion, Challenges fill a critical gap (even if they’re similar to Crisis Pools from Hammerheads). I plan to mostly rely on these, as opposed to building complex NPCs (aka GMCs) ahead of time. Challenges might represent escaping a zombie horde, battling an enemy ship, or similar dramatic situations.

Limited Doom Pool

Without getting into details about the differences between the regular Doom Pool and the Limited Doom Pool, the latter feels like a good match for my setting. It essentially replaces Plot Points (Cortex Prime’s metacurrency) for the GM, and can be used for anything that Plot Points can do, but also to add to dice pools to increase the difficulty when dramatically appropriate. The GM can grow the Doom Pool when players roll hitches (i.e. ones), which is a nice way to bank these for later, rather than having to apply Stress or other consequences immediately.

Playing Online

I also had to figure out how to best play Cortex Prime online.

Official Digital Tools

These have in progress for a while. Digital character sheets and dice rolling are supported for Tales of Xadia, and look quite nice. But that doesn’t help custom Cortex Prime games like this one.

As a side note: I feel that Cortex Prime really needs this feature. It will be awesome for creators when they can create games online by easily picking and choosing trait sets, mods, etc. and having the system automatically generate a character sheet, handle rolls, etc.! In an ideal world, I could even envision a wizard-like UI that walks GMs through the game creation process and suggests the appropriate trait sets and mods to use based on their goals for the game.

But there’s no ETA for these tools right now. With Dire Wolf’s acquisition of Cortex Prime last year, all bets are off - but they do have good experience in the digital space, so fingers crossed.

Traditional VTTs, e.g. Foundry

Foundry seems to have pretty solid support for Cortex Prime. I’ve heard good things about it, and it’s worth checking out, especially if you’re already using Foundry. I’m not sure about other VTTs’ support for Cortex Prime, like Roll20 or Fantasy Grounds. It’s a bit overkill for the experience I want here, though.

Google Sheets

As someone who tends to prefer “theater of the mind”, I usually don’t need a full-blown VTT. I generally like using Google Sheets for character sheets when playing online. I’m not a visual artist, but I’m happy with the one I came up with. I was able to lay it out like I want, and use some fun colors to make things pop.

Discord + CortexPal2000 Dice Bot

Discord is my application of choice for video and voice. It has great dice bots as well. But because of the way Cortex Prime’s dice pools work, most Discord dice bots don’t work well for this game. Luckily, there’s a Cortex specific dice bot that works great: CortexPal2000.

So that’s what I used for my game, and the feedback was very positive.

Setting and Adventure

Aside from the rules, I also had to come up with the content for my Setting and Adventure. Cortex as a system is straightforward enough that I don’t need system specific resources- I just need the content. One fantastic resource is tvtropes, and I spent a bunch of time browsing pirate and zombie related pages on that site.

I also bought and skimmed a bunch of other pirate and zombie RPGs. For example, Savage Worlds: Pirates of the Spanish Main has great system neutral info about the Caribbean, pirate ships, roles, etc. I even bought my first Gurps books, which I never thought I would!

I came up with a starting situation and a list of possible scenes. This wasn’t so much a cohesive adventure, but rather a collection of scenes to play through, as the characters encounter zombies for the first time and deal with the fallout, fast-forwarding to the next scene as needed.

Finally, I wrote down the following set of worldbuilding questions to go through with the players at the beginning of the session. I figured that this would help the players get invested in the game, and allow me to facilitate a more engaging session by touching on their choices.

  • Primary Nationality (English/Spanish/French/Dutch)
  • Privateers or Pirates (Privateers have a Letter of Marque)
  • Ship’s Name
  • Captain’s Name
  • Home Base
  • Who’s your Rival, and why are they looking for you right now?
  • Most recent adventure and most valuable haul you obtained?

Running the Game & Learnings

I was admittedly more nervous leading up to this game than I usually am. I frequently run new game systems, but this one was more intimidating for me. I kept second-guessing my mods choices right up to the session…

But the session went very well overall. Of course, I was lucky to have a great set of players! I was upfront about expecting some rough edges, and they were understanding, really leaned into the setting, and rolled with it.

I think everyone had fun with the setting. But I realized afterwards that I missed some opportunities to let the players discover the cause of the zombie apocalypse. I’ll have to work some of those elements in the next time I run this game.

The trait sets for characters and ships seem great. The mods and other tweaks seem good as well. My players liked how I ran ship combat, as a challenge, i.e. players taking turns, followed by the enemy ship. The players assemble dice pools that use the ship’s attributes and distinctions, but their own Role trait. I did realize that I have to be flexible about letting them use their own traits as opposed to the ship’s for some actions (e.g. one person tried persuading the captain to take a certain course of action; this was more about them than the ship).

I also need to tune my Challenges a bit, such as dialing in the size of the dice pool, which affects the challenge’s difficulty and length. I need to learn when to use d8 vs. d10, and how many. The book has guidelines, but those only go so far. I also need to find ways to gracefully exit Challenges when appropriate.

The Discord dice bot works very well. I got feedback that it was faster and smoother than the point and click experience in Roll20, which one of the players had used for a recent Cortex Prime game.

As for Cortex Prime itself:

It’s too early for me to fully assess it after just one session, but I had a great time running my first game. I’m increasingly leaning into an improv GM style, and the system and setting really lends itself to that!

Creating my setting was fun and rewarding, even if it felt a bit daunting. Now that I’m more comfortable with the system, creating the next setting should be a lot simpler. In many ways, this feels like a perfect option to realize my own setting ideas, so it’s a great addition to my RPG toolbelt.

I really want to play in person at some point. My sense is that Cortex Prime would really shine when sitting around the table and rolling physical dice, due to the tactile nature of the system, such as picking out which dice to use for value and effect. But Discord and Google Sheets worked well overall, and online play could be even better once the official digital tools come out.

I’m looking forward to more Cortex Prime in my future!