System Overview: Caltrop Core.
For three weeks, I’m exploring various ttrpg systems and what makes them tick, as per what was voted on in this poll. This week I’m going to dive into Caltrop Core!
Caltrop Core, by titanomachy (also known as Lex Kim Bobrow), is a genre-neutral SRD that uses d4's. It's flexibility sits in how you use the layered result system; from dice, to dice & tokens, to a pack of cards.
Let's take a look at the core pieces of this SRD!
Cybercore-Revelation, by Xelsius @ Forward Lightning, & A Night of Possibilities, by Vinicius de Souza.
The Results Table.
The actual SRD document for Caltrop Core is rather concise, and that's because pretty much everything in the game revolves around the Result Table.
When you describe an action by beginning with the words "I want to…", you roll 1 or more d4's. Your result is determined by the highest roll, and each level of the result is different.
Absolute Failure - You don't get what you want; things get worse.
Partial Failure - You don't get what you want (but possibly gain a benefit).
Partial Success - You get what you want, but with a complication.
Absolute Success - You get what you want, and more.
This is the centre concept for Caltrop Core: once you know this, you can iterate on this as much or as little as you want! I think this is why Caltrop Core can be such a great option for a first time game-maker: you can add some flavor to the core roll, use some basic modifiers built into character creation, and you're good to go.
That being said, there's more layers that can exist in a Caltrop Core game if you want there to be. One way is how you get to the results listed in the table above, and the resolution tools available have some interesting options.
Let's take a look at some of the examples available in the deep deep pool of Caltrop Core games!
Full Moon Investigations, by Patchster0730, Party Animals, by Dani Belonia, & Ceremony in Shadow, by tlando.
Stat Pools.
The most common resolution method uses dice pools pulled from your PC stats. These stats often are built out of an array, and then modified by a character class or background, such as in Full Moon Investigators: in this game, you have Bark, Bite, Brains & Bullets. You assign a 1, 2, 3 and 4 to each, and then gain modifiers to certain stats in certain stages of the game, depending on the background that you take.
Alternatively, you can create your character from a number of different pieces, like the options available in Cybercore Revolution. Since this game has 12 Skills instead of just 3 or 4, you have an opportunity to build a more highly specialized character. Instead of choosing a single character class, you can build a character out of Traits, Vocations, & Specializations, allowing you to hone in on just a few abilities, or allow yourself a generalized advantage in as many as you can.
In Dead Armour, your character has a stat array, but they don't have any backgrounds to improve their skills. Instead, this game introduces an additional mechanic: Tokens.
Dead Armour, by tim zee, I'll Be Taking That, by porchlightdusk, & Ghost-Fi, by aghostofeli.
Tokens
Tokens are a form of player currency that can be spent in a number of different ways in Caltrop Core. In Dead Armour, tokens are currency earned through role-play in Downtime between scenes, that can then be spent to avert disaster or find some crucial resources.
Similarly, in Hexfall, tokens are used to adjust the outcome of a roll, provide a narrative boost, or activate character actions assigned to your character class.
In The Stars Will Not Go Out and Party Animals, players gain and spend tokens through various prompts, which then fuel their dice pools. These prompts are often tied to character backgrounds, allowing your character abilities to remain unique and specialized.
There's also a fun twist you can add to Caltrop Core games by adding another form of resolution or randomness: Cards.
Or4cle, by 1eona, Hexfall, by titanomachyrpg, & The Stars Will Not Go Out, by RJKGames.
Cards
In the SRD, Lex mentions that Caltrop Core can also accommodate other toys in its game design, such as playing cards or tarot cards. Cards are often a great way to add randomness into a game that allows the group to play without a GM, or to provide results that don't map onto a success/failure matrix. Here's a few examples of how designers have decided to include cards into their Caltrop Core creations.
Or4cle, by 1eona, is a game that combines the d4 rolls with tarot cards, which are used for character & story generation, and might allow the game to become GM-less in the process. The Major Arcana are used to determine the hook of a story: such as investigating someone's lover if you draw The Lovers card, or a world-ending threat if you draw The World. The Wands are used for plot twists, Cups for a patron, Swords for Antagonists, and Pentacles for rewards. When it comes to character generation, each of these decks are also used to give you details about your character, allowing randomness and interpretation to both have a role in the game.
Meanwhile, Ghost-Fi pairs a pack of playing cards with the dice to determine details that connect ghosts to the world around them. The suits are categories of Tethers: things that keep the ghost connected. The symbols on the cards can occasionally offer up unique encounters, such as increasing Spite - a corrupting currency that could affect your ghost's ability to cross over to the afterlife. Since Ghost-Fi can be played solo, these cards allow for unexpected obstacles to face your character, even if you don't have a GM to come up with NPCs and enemies to stand in your way.
Rat Guardian by FiloHazard, & Space Taxi, by gothHoblin.
The Playground.
All of the examples I've talked about so far are just a small taste of what you can do with Caltrop Core. The basic mechanic is very simple, which means that you as a designer can take a lot of ideas from other games that you like and weave them into the basic rules to create an incredibly unique and inventive game.
For example in I'll Be Taking That, you wager items from your goblin hoard (read: inventory) to increase the number of dice you roll. This replaces the stats, although it doesn't have a token economy like Party Animals.
In Hexfall, stats are not even included in character creation; you simply roll 3d4 for every interaction, but the rules change depending on the kind of encounter you face.
In Rat Guardian, players have to pair up: one Rat player for every Resident player. The game's pacing happens through a series of Beats, which involve goals that the guardian Rats need to work to help their fellow humans achieve. In order to achieve these beats, Rats and Residents can sometimes pool their dice in hope of increasing their odds.
Caltrop Core is an excellent option for folks who want a fairly easy-to-understand resolution system that can be modified to fit a broad number of genres. If you're a new designer who wants an easy system that will allow you to try your hand at this hobby, or if you're a designer who wants to play with a neat mechanic and watch it interplay with a basic system, you might want to check out Caltrop Core.
Let's take a look at a few more Caltrop Core games that might interest you!
FishBlade on a Bright Reef, by PlaceHead Here, is a game about FishBlades helping human souls escape a Reef and move on to the afterlife.
NIGHTHAWKS is a game about lonely people in a Diner, who have to make a choice between risking rejection or succumbing to isolation.
Magic Moth Island, by LeightonConnor, is a game about animals defending their magical island from human invaders.
Duat, by Deep Light Games, is a game about recently deceased souls overcoming trials in the afterlife.
OK See You, by Bebop Tabletop, is a game about immigrant families and convenience stores, inspired by shows like Kim's Convenience.
Wardens of the Sundered Realms, by Groovy Dad Games, is a game about beast hunters in the service of the High King.
Final Notes...
You can check out my folder of Caltrop Core games on Itch, if you want to see what I've found so far.
If you like what I do, you can always leave a tip at my Ko-Fi!














