Magic and Its Equivalents
Magic is such a distinctive aspect of role-playing games that we'll look at it in a separate section. Note that for magic you can substitute psychic powers, spiritual power, mental energy, or any other concept that allows characters to influence the world, themselves, or other characters, by means not available to us in real life. Science fiction games often posit advanced technology that is, as Arthur C. Clarke observed, indistinguishable from magic.
The use of magic is commonly restricted to a particular class of characters, often called mages, magic-users, or spellcasters. The purpose of this arrangement is to establish complementary classes of characters, one that is good at conventional physical combat and one that is good at magical combat, which encourages the players to create mixed parties containing members of both classes.
In tabletop RPGs, where it's up to the GM to decide what is and isn't possible, players can imagine all kinds of interesting things to do with magic. CRPGs are unfortunately limited by the fact that the software has to know how to implement any spell—and of course players expect a visible manifestation of the spell as well, which means creating animation and sound to go with it. Magic is most often used as a weapon or a shield and as a means of temporarily improving the values of the party characters' attributes and harming the attributes of enemies.
Because magic doesn't exist in the real world, you can't assume that your player will know how it works in your game world. If you include magic in your game, you must define what kinds of things magic does and how to invoke it. You must also create a way to limit the amount of magic available, just as characters must have limited strength and health. Typically, when a spellcaster uses magic, he does so in a particular instance called casting a spell, the effects of which are usually immediate. (Few spells in games take time to begin working.) Some spells are over and done with right away, more or less corresponding to a shot in a strategy game; others may have a lasting effect that ends after a certain amount of time. The effects of magic spells are almost never permanent in games. Permanent changes are too significant to happen frequently, so any permanent change is normally made by the leveling-up process.
Dungeons & Dragons uses a rather awkward system for placing limits on magic, requiring a character to "memorize" spells which, once cast, disappear from the character's "memory" in the same way that a gun consumes ammunition. The character must have time to rest and rememorize the spells before she can use them again. This was convenient in tabletop games where the players had to keep track of their spells by hand. Now that computers can do the bookkeeping, however, most designers prefer another system in which each spell consumes a certain amount of magical power, or mana, when it is cast. A character's definition includes a status attribute for the amount of mana the character has at the moment and a characterization attribute for the maximum amount that she may have. Drinking magic potions or simply waiting for time to pass may restore the mana. This system
permits the character to cast any combination of spells that she knows, as often as she likes, until her mana is gone.