Notion: Magic System Basics

I've been thinking about magic systems this week. I've been pondering a while on a Scrabble-tile-based system for Zludge. But, as I often do, when I get stuck I explore the basics to try to figure out what the factors are.

First of all, there's a vast variety of magic systems. For examples, I've just been looking at D&D, GURPS, Fudge, and FATE--and that's been enough! There's also related and parallel magic-like systems, such as psi, ritual/incantations, and superpowers.

I think the great variation of magic is just because every fictional world tends to have its own magic/supernatural rules--what's possible and how hard it is to do. So one magic system is definitely not going fit all games, just in terms of flavor.

The other side of that flavor coin is the rule mechanics. I've identified three concerns here:

First, how detailed is the system? That is, is it based on just a handful of guiding principles, a few tables of modifiers, or a complete book laying out every spell in detail? Detail may be a boon or a curse, depending on your play style.

Secondly, how diverse is the magic that needs to be modeled? For instance, is magic in this world basically only telekinesis, where physical objects can be moved and that's it? Or are we modeling a long tradition of every diverse occult effect, from summoning demons to levitating to blasting fireballs, from combat casting to potions to hour-long rituals?

Finally, is the magic system balanced? This means between uses (so casting a certain spell has a consistent cost), within the magic system (so a mage specializing in divination gets just as much of the limelight and story power as one specializing in evocation), and with the rest of the game mechanic (so that non-mage characters aren't overshadowed by the mages).


With these concerns of detail, diversity, and game balance in mind, we can look at how various general mechanics satisfy these. First, there's the issue of how magic is purchased by a character. One option is as skills--where each use requires a check or roll, just as with any other non-magical ability. Another option is stunts--one-time uses that a player usually checks off when used (though not necessarily: a stunt may be more like a feat, usable at will). Additionally, there might be power levels, which usually determine the strength of effects. Power levels usually operate in conjunction with skills or stunts.

These purchasing modes--skills, stunts, and power levels--provide a means for game balance. However, magic could be something simply accumulated through play. D&D's wizard's spellbook and Unearthed Arcana's incantations work a bit like this.


So, aside from how the magic is purchased, what is the basic game mechanic? The first is the exhaustive, specific spell list. D&D uses this approach (where each spell uses a stunt-like spell slot), but so does GURPS (where each spell is a separate skill, with a diverse tree of spell-skill dependencies). This could also be used very nicely on a small scale, as with Fate's example of Pyromancy stunt magic. The advantages of the spell list is extensive detail and, assuming sufficient playtesting, good game-balance. But detail is its own curse--now every time a spell is cast, the books need to come out to check the rules. Also, one is not meant to adlib new spell effects when you have a spell list.

A second mechanic is the general skill. So, unlike GURPS one-skill-per-spell, what I mean here is that one or more skills determines success in a wide variety of endeavors. In short, details such as range, duration, and effect are not set by the spell itself, but adlibbed according to some guidelines. This is seen in simple Fudge-like magic systems, such as Fate's Improvisational Magic. In a very simple system, the GM specifies how hard a certain affect would be to achieve and the player justs roll against a single Magic skill to determine success.

Often the skill roll is combined with power-levels. GURPS psi works a lot like this. For example, the character's telekinesis skill determines the control the character has, but her telekinetic power determines how heavy an object she can affect. (GURPS psi skills are defined so narrowly to be practically a spell list, however.)

Stunts could be used generally too. For instance, a character could perhaps produce 3 Illusions a day, but determine at the time of casting the details of those illusions.

A third mechanic is the combo skill. This is essentially run as a per the general skill mechanics, but each spell success is determined by some combination of skills. This could be an averaging, one roll for each skill involved, or just rolling the lowest skill. Fudge's 4x5 and Gramarye systems and GURPS Magic's improvisational rules work like this (using a combination of college/verb and realm/object skills), as do D&D's incantations (using non-magical skills).

I don't know of any combo-stunt systems, but it seems such as system would certainly be possible.

Finally, magic might use some completely separate mechanic, such as using playing or tarot cards, marbles, or Scrabble tiles. But usually these can be boiled down, or at least compared to, stunts or skills.


So, from what I see here, a magic system is basically going to let a character roll some skill or invoke some stunt to produce an effect. This is because skills and stunts (and power levels) are the core RPGing mechanic and, to maintain game balance and functionality, any major/integral magic system should be in these terms.

So, the first question is to determine the flavor and diversity of the magic you want to model. Then, look to what detail you want to use to model this. With high diversity, high detail will be a major undertaking. Also, your game system will probably direct you on this--high detail systems (such as D&D and GURPS) favor detailed spell lists, while Fudge prefers general and combo skill rolls. The advantage of detail is all the consistency and game balance kinks can be worked out beforehand. The advantage of less detail is that you can make it up as you go, letting player and GM creativity shine.