Premise: a character class provides players with an interface to the game world and a place for their characters within it. (See yesterday’s post on classes.)
There are a couple of major schema for constructing character classes. Most games use more than one.
Class by Combat Role
You separate characters by how they fight. This is the simplest distinction between Dungeons & Dragons‘ fighting men and magic users, and it goes back to Chainmail. The fighter/wizard divide (or lack thereof) is arguably the definitive problem in character class design.
Basically, in Chainmail, there were guys who fought other guys with swords and polearms. Then Gygax added wizards, who functioned as artillery. So, going into Dave Arneson’s original game, you had these two basic types of units.
In 1974 D&D, they were represented by two overlapping but distinct systems: combat and magic.
In tabletop games, D&D 4e is probably the most rigorous example of this approach. Not only is every class and monster defined by a combat role, but those roles are transparently explained to the players right there in the rulebook.
Virtually every Everquest-descended MMO is built like this. (The extent to which Everquest itself follows this model is a longer discussion.) The most transparent about it is probably City of Heroes, which marries Everquest combat roles to character concepts while staying fairly abstract about both.
This is a somewhat circular methodology, though. Since D&D, it’s become imperative to have certain classes if you’re going to do a class-based fantasy game. And if you’re going to have combat, there’s a strong push to give each class a unique place in combat.
(That last bit’s especially true of MMOs, where problem solving comes down to money or combat, no matter what style the game adopts otherwise. )
Classes by Concept
You have a fictional persona in mind, so you make a class for it. By volume, this is probably the biggest driver in class design.
D&D’s original classes (fighting man, magic user, cleric) were driven by combat role and need. The first supplementary class,* the thief, appears to be driven more by concept.
The thief appears to be loosely modeled on characters like Fafhrd, the Mouser, and maybe Bilbo Baggins. (Gygax didn’t like Tolkien all that much, but that didn’t stop him from using Middle Earth stuff where he liked it or thought it would be commercial.)
He has the skills one would guess a thief might need, as well as one which seems rather particularly borrowed from the Mouser: the ability to use magic scrolls.** In the process, he introduces a third system to D&D. Mechanics supporting fiction, we are go.
Classes to Fill Holes
Your system’s missing something, so you make a class to fix it. D&D’s cleric is the classic example of a class created to fill a hole in a game or campaign. Dave Arneson had one player playing a vampire. As Mike Mornard recounts:
Well, after a time, nobody could touch Sir Fang. Yes, that was his name.
To fix the threatened end of the game they came up with a character that was, at first, a ‘vampire hunter’. Peter Cushing in the same films.
As the rough specs were drawn up, comments about the need for healing and for curing disease came up.
This is pretty much always a supplement for another design scheme, and many games that start strictly adhering to another approach evolve in this direction over time.
Classes as a Template Layer
Your system operates on a point-buy or other system, but classes ease new users into creating a character.
D&D 3.5 almost works this way. One of my favorite video games of all time, Hero’s Quest/Quest for Glory I, works this way. Ultima Online‘s current character generation process works this way.
Vampire: The Masquerade‘s clans were intended to operate this way, but quickly became vital fictional concepts in and of themselves. By the end of the Revised Masquerade line, fictional concept drove class design completely. How that played into the approach taken to Vampire: The Requiem, and how the vision changed over the course of that line, is the subject for another article.
Classes on a Spectrum
You have certain “pure” mechanical concepts (melee, magic, stealth) with classes that represent them (fighter, mage, thief) and then a series of classes which exist between those.
This is the fighter-cleric-mage spectrum of the original D&D. The Mass Effect series is also built this way, and quite elegantly. Tunnels & Trolls primarily follows this method, though it’s also evolved quite a bit over the years.
Classes by Convergence
Your game has no formal classes, but character optimization favors a small number of builds. You probably lie awake at night worrying about tank mages. Later designs building on the same system end up centering around these builds more than the original open, underlying system (usually based on skills).
Ultima Online is the poster child for this. UO wasn’t designed for classes, but they perpetually emerged from each revision of the skill system.
GURPS is often played this way, though I’d be a little afraid to say so on a message board.
Exalted looks like it’s a class-by-concept scheme, with all of the D&D standards scaled up, but many people play it as a convergence scheme, and that’s the current approach to its mechanical design.
* Class was a slippery concept in 1975, something I’ll treat in the future. But by the definitions later games would extrapolate from D&D, Greyhawk D&D has four classes.
** This seems to me to be directly from “The Lords of Quarmall“.