Every one of us here in R&D is a game tinkerer, and we all like to tweak our games with our own ideas of how to make them more fun. And where better to get original ideas than to borrow and steal them from other games?
Today, we borrow and steal from the Burning Wheel, a role-playing game of some repute. The game has some things I like and some things I don't, and a couple things I love. Those are the character traits called beliefs and instincts.
Beliefs are statements about what your character believes to be true and what shapes how he interacts with the world. They aren't broad, sweeping statements about general philosophy - these are beliefs that influence his life closely. The belief Gruumsh is a cruel and evil god doesn't tell us anything about how your character acts, but saying The god Gruumsh and his followers deserve nothing more merciful than swift deaths does.
Each belief a player chooses - and he should have two or three - carries a pair of statements. First, it tells the DM and the other players something distinct about the character - in this example, it conveys a hatred of Gruumsh and his followers, including most of the orcs the group will meet. Second, it tells the DM that the player wants to come into conflict with servants of Gruumsh and orcs and begs for a tense scene wherein the character isn't immediately allowed to slaughter such servants, or must ally with them.
Burning Wheel recommends choosing three beliefs, each with a different focus. The first connects to why the character is an adventurer - he or she can be exceptional without risking life in pursuit of... what? Examples: My father's spirit shall never rest until his murderers are dead, or My life is worth nothing if I am not looked upon as a hero. The second belief should connect the character directly to the campaign: Hommlet is the light in the darkness, and it must not fall, or the master of the Temple of Elemental Evil is my son, and therefore my mistake to put right. The third belief becomes a goal for the future, something for the DM to hang future stories on or make references to: The sorcerer who taught me will one day claim a payment too great for me to bear, or once Hommlet is safe, its civilizing influence must be spread.
The line between motivation to be a hero and connection to the story can be fairly fuzzy, and they're looking pretty similar to me as I think about it now. I wouldn't put a lot of pressure on fitting those three specific lines for your beliefs. Instead, just pick two or three that (a) clearly state something about how your character acts and sees the world and (b) connects your character to the campaign. The second is also known as giving the DM story hooks, and is almost unavoidable if you do the first right. If I had to add a stricture for one of the beliefs, it would be to create a reason for the character to be part of the party.
With five or so players all making beliefs, you can end up with a spread of stories begging to be explored but not compatible with each other. What do you do when one player comes up with the goblin nation of Darguun is a threat that must be wiped away and another chooses Darguun can be peacefully integrated into the world's political landscape, and yet a third decides that goblins are insignificant beings undeserving of the slightest attention? This situation is why players should discuss their characters' beliefs with each other during character creation, the same way that they discuss class makeup so you don't end up with five warlocks. (The three above beliefs wouldn't be the end of the world - roleplaying those three characters in a party together would trigger lots of interesting arguments! But the players should all be interested in that before they commit to it.
In the same fashion, beliefs should be discussed with the DM. If the DM was planning an explorer's game a continent away from Darguun, those three players (or at least two of them) will be disappointed. The DM and players should discuss beliefs in the same way that they discuss the nature of the game the characters are for, so everyone is interested in the game's subject matter. You already know to discuss game subject so the political-focused bard doesn't feel out of place in the gritty war campaign, I'm just reminding you to treat beliefs the same way. On the other hand, if the DM is planning an explorer's game and everyone wants to make beliefs involving Darguun, the DM should give some thought to shifting the focus of his campaign.
I like beliefs more than alignment. Good and evil are more black and white than I like to have in my games, and beliefs are much more evocative. Saying I will prove my superiority to all creatures is more descriptive than Evil, and failure to protect the weak is as foul as ravaging them myself says volumes more than Good. You can replace alignment with beliefs or use them side by side.
If you include beliefs in your game, you might want to include a reward for when characters hew to them. Two possiblities come to mind. When a character follows his or her belief, the character gains an action point. If this happens too frequently, use "when a character follows belief in the face of adversity" instead. Action points are functional, but I have something more dramatic in mind. Give each character has a mighty power that he or she can only use after following belief despite fierce opposition. This could be a combat power or an out of combat power, but it should be big, and a player shouldn't get access to it more than once every few sessions. Off the top of my head, you could use a daily power 15-20 levels higher than the character for this power. When your level 3 wizard who believes the Magus Council is corrupt and must be cleansed confronts the council while surrounded by guards, he might unbelievably summon a black devourer in the middle of the council chamber. It is a dramatic device and a reward for playing the character.
This being a long post, I believe I will address instincts next time. As always, your comments are welcome.