Changing Magic

You must keep certain things in mind when altering the outer trappings of a game system’s magic. First, and most important, is that characters who study magic extensively (wizards, priests, and, if you allow them, bards) are the only characters able to cast the really cool spells. So there has to be some reason that non-spell casters cannot cast these spells. In some systems, such as DragonQuest, any old fool can cast certain kinds of spells.

The biggest problem with modifying magic is keeping game balance. You must be careful not to drastically change the power of magic when modifying the way magic works. There are three things to keep in mind:

  1. The availability of spells.
  2. The ease of use of spells
  3. What it takes to stop spells
The Availability of Spells
In standard AD&D magic, creating new spells takes a lot of time and money, and even then successfully creating a specific spell is not certain. Spells that are already in existence must be found, stolen, or purchased. Certain spells are meant to be rare, only used by a few sage wizards. Sometimes, the search for a coveted spell is the catalyst for an adventure.
The Ease of Use of Spells
Some spells are easy to use. One segment’s worth of casting, a couple of commonly found components, and the spell is finished. Others require a lot of time to cast, rare ingredients, or that the caster be in a specific situation.
What it Takes to Stop Spells
The AD&D wizard is very easy to stop. A silence spell from another spellcaster will preclude any new spells from being cast, except for the very few that have no verbal component. If the caster takes damage during casting, the spell is almost certain to fail. Tying up or otherwise restraining a caster makes it virtually impossible to cast spells that require either somatic or material components.

Balancing Act

When modifying a magic system, you must keep those three factors in mind. If you decrease the effects of one factor, you should increase one or both of the others. If you make spells more easily available, you should make them harder to cast. If you make them easier to cast, you should probably make them easier to stop.

Note that if the magic system is not meant for player characters, you do not need to worry quite as much about game balance, as long as there is a physical reason that the PCs cannot use the new magic system. However, game balance should apply equally to both player characters and non-player characters.

When modifying the style of magic, I tend to leave the very weird magic to NPC races—societies in other planes, and from planets in distant crystal shells. Also, the strange magic systems, such as mechanical magic or mathematical magic, should be reserved for special adventures.

Very Different Ways of Magic

When making up ways of magic for strange places the players visit, you can go wild. A system which uses specific crystals, combined with the spell caster singing specific notes, causing the crystal to resonate, for example. Or a world where all magic is created through the use of precise dance steps. Use your imagination.

Different Ways of Magic in the Same World

Different Ways of magic are almost always incompatible with each other, unless you, as Dungeon Master, wish to have different ways with a common predecessor. Different Ways of magic also will usually have different components for the similar spells, assuming that both Ways use components. In other words, a practitioner of one Way will be unable to learn spells from a practitioner of another Way.

In the Esoteric examples of magic, a Gypsy wizard cannot learn spells from a Celtic wizard, and neither can learn spells from the more common wizards of civilized Highland. Nor can a wizard of civilized Highland learn from a Gypsy or Celtic wizard. And a wizard from the Astrotech Rim wouldn’t even recognize any of their spells as magic. It’ll all be barbaric gobbledigook to her.