Ars Magica style magic in GUMSHOE

I couldn’t sleep last night. I woke up at 3 AM with a project on my mind, a conundrum I’ve been swishing around in the mental stew I call my mind. How would I mimic Ars Magica style magic in the GUMSHOE system? So I slipped out from under the warm covers and headed to my office, where I finished reading Paul Pope’s Batman Year 100. It was too early to turn on the computer, and really all I needed was to settle my swirling mind. I don’t like Batman stories overmuch, but Paul Pope is a talented artist and he does put his finger on the essential characteristics of a good Batman story: overwhelming odds, a hint of paranormal but nowhere near a full does, daring escapes, Bat-gadgets, and secret friendships. The story alone would merely limp along, but Pope’s art pushes it over the edge into Successland.

GUMSHOE, which I regularly mistype as CUMSHOE (a whole different type of rpg system, I imagine) was designed by Robin Laws, one of the few full-time game designers in the world of paper and pencil RPGs. It’s a simple system that automatically grants marginal successes to players, a system that gives them the clues of an investigation adventure without necessarily telling them how the clues fit together. We’re playing it tonight. I’ll run the introductory adventure in The Gaean Reach for the family and we’ll see how it goes.

Ars Magica has a magic system that was once novel and is now as inventive as an Edsel. It combines Five Techniques, essentially verbs that describe a spell (“I create”, “I destroy”, “I control”) with Ten Forms, objects that the spell effects (“Animals”, “People”, “Fire”). Thus, a fireball spell would combine the character’s score in the Technique for creating with her score in the Form Fire. Simple enough, but it quickly gets bulky by modifying the simple x+y+die roll formula with bonuses and penalties for a multitude of conditions. But I don’t want to talk about how convoluted an inelegant this system is in play, I want to talk about how to port the style of the system over to GUMSHOE.

Transferring a character’s abilities from one system to the next is nearly effortless. Both games have a Sneak skill, for example, both games have an Investigate skill, easy peasy here. But GUMSHOE doesn’t have a magic system. Essentially, each ability covers a variety of aspects within that scope of activities, and if a character wants to try something covered by an ability they roll a dice and succeed (more often than not). That’s not going to cover the complexity of the magic system.

What I’d do is make each of the 5 Techniques and 10 Forms an ability in and of themselves. When a player wants to cast a spell, she combines the score of the Technique with the appropriate score of the Form to generate a Flexible Pool, which is what I’d call it. Or a Temporary Pool, maybe. To succeed with a low level spell the difficulty is 4. Roll a four and you succeed. A low level spell equals a level 5 Ars Magica spell. The difficulty for a level 10 spell is higher, maybe a 5. Level 15 spell higher still, you get the idea. A player can spend points from either of the Ratings that make the Flexible Pool.

An example, one that depends on knowing how the GUMSHOE system works. My wizard is a creation specialist. At character generation I give him a Creation Rating of 8 and a Rating of 1 in all ten Forms. In play, I want to cast a spell that throws a bolt of fire at an enemy, so I cast a level 20 spell called”Pilum of Fire”. I need to succeed against a difficulty of 7. I’m only rolling a d-6, so to succeed I need to spent points from my Flexible Pool, which for Creation-Fire is 9. I spend 4 points, 3 from Creation and 1 from Fire, roll a 3, and zip-a-dee-d00-dah fry the bugger. Later, I want to grow a vine so I can climb down a hole in the ground, the kind of thing adventurers want to do now and then. There is a suitable patch of weeds nearby, so I cast “Conjure the Sturdy Vine”, a level 5 Creation Plants spell. Using the Flexible Pool for Creation and Plants, which is only 6 because I spent 3 points from Creation already, I need to roll a 4 to succeed. Do I want to spend another point? I could spend it from the Creation Rating or the Plants Rating. I don’t, roll a 2, and fail. Damn fickle magic.

That’s great for spells I know, which in Ars Magica are called formulaic spells, but the game also has spontaneous spells, spells that I can dream up on the spot and cast away, if I can conjure the necessary magical energies. How do we handle that in GUMSHOE? Easy. We double the difficulty. If I didn’t know the spell “Pilum of Fire” I could still try to cast it. I’d combine my Creation Rating and my Fire Rating to form a Flexible pool, then spend points to achieve a difficulty of 14. If that’s too steep, which I’d find out after playing a few times, maybe I only increase the difficulty by 5. Those picky little rules questions would work out in playtesting.

So while I laid there last night wondering how I’d do it, several hours later I’ve dreamed up a system that I could test. It’s a fun project.

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5 Responses to Ars Magica style magic in GUMSHOE

  1. When I first heard of this project I was interested, but somewhat dubious. Knowing that you are on the case gives me a significant degree of reassurance. Looking forward to where this ends up!

  2. Matt Ryan says:

    Wait, wait, I’m not on the project. I’d like to be on the project, and have submitted an application, but I’m only speculating. I think Ars Magica has needed a rules-lite shot-in-the-arm for some time, something simple to introduce new players to the wonder and awesomeness of Mythic Europe and the Order of Hermes.

  3. Haha Matt, thanks for clarifying. Still, I’d be interested in your efforts and where this ends up…

  4. Imrryran says:

    I see one main issue : the conditions and modifiers that makes the Ars Magica system quite uneasy during game is also what makes it different from most other magic system. It provides a medieval feeling, not a super-hero one.

    I think FATE is a better fit, complex conditions and modifiers being replaced by simple aspects designed on the spot, depending on the scene context, by the table.

    I toyed with that idea in one of my games (and blogged about it but only in French) and it went really well once the table understood the basics for magic in Ars universe and was providing aspects, boost, etc. in relation with it.

  5. Chris Jensen Romer says:

    How many points would you assign to the 15 Arts? I figure 65 gives a young magus, 90 an experienced maga and 150 an Archmagus.

    Auras can be halved round down. Spells can be mastered by assigning them a specialist pool at 2:1.

    Fatigue needs representing. Penalty of 1 cumulative for each spontaneous spell after the first without resting?

    I’m not on the project either but I do know Gumshoe. 🙂

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