When it comes to tabletop roleplaying games (RPGs), the subject of family often comes up only in terms of how having a family can complicate a player-character’s (PC’s) life. And make no mistake; it can, particularly if the PC in question is playing somebody who isn’t a complete and total sociopath. Meddling with a PC’s family is even appropriate for a lot of genres: superheroes, for example, are always forced to deal with somebody menacing their spouses or aunts or whatnot. And then there’s the classic “sudden revelation of a previously-hidden family connection between a protagonist and antagonist”: the Star Wars series famously picked that trope up in The Empire Strikes Back and only put it down… well, OK, the series won’t ever put that particular trope down voluntarily. So, the point here is that you can easily justify using a PC’s family members as a straightforward and simple way to provike an emotional conflict. Nothing wrong with doing it, either.
But there are in fact other ways to use the concept of family in a RPG; ways that might prove of interest to a GM looking for ideas. Or just a GM who is trying to simplify things. Because goodness knows, but a RPG campaign often needs all the simplification that it can get.
The most obvious alternative way to use “family” here, to be straightforward about it, is to embrace thinking in terms of stereotypes. Make all of your local petty thieves members of the same extended clan. Establish that one particular family produces all the Genius Hyperdrive Engineers in a campaign. Demonstrate to your party that having a particular last name more or less guarantees that its holder couldn’t carry a tune in a bucket. Establishing those rules gives the GM two different, somewhat contradictory advantages; one, it allows everybody playing the game to have an easier time of it keeping straight in their heads which person is whom, and what those people do. This can be extremely helpful in a tabletop RPG, given that so much of the action is going on in people’s heads — and sometimes nobody thinks to take notes. Two, having these kind of rules of thumb can make for an entertaining game session when you throw somebody at the party who doesn’t follow the previously established rules. Don’t do it too often, but you can do it every so often.
The second trick with using family doesn’t always work for every campaign, but in campaigns where it can work it can work very well: have your players come up with familial relationships for everybody that they meet on a regular basis. Don’t give out extra experience points or rewards for them doing it, mind you: if you do, then the players will just blizzard you with ever more elaborate (if not actually baroque) relationship trees, especially if doing so can score the players advantages to their die rolls. But if the players show a particular interest in a non-player-character (NPC), then ask them: “Who is this person, and what is their three-sentence story?” Do it right, and the players will cheerfully do a lot of the NPC prep work that you’d otherwise have to do. Not to mention give you a handy way to do that aforementioned complication of a PC’s life.
Lastly, and this is more of an internal thing for a Game Master (GM): family issues are a marvelous way to justify a NPC acting in a certain way (when the real reason for the NPC’s action, of course, is because it’ll help the plot along). Everybody knows the “they took my son hostage so I have to do their bidding” or the “If my family ever finds out my Dread Secret then I will be disowned forever!” cliches, not to mention the “straight-up revenge one” (which produced one of the greatest scenes in movie history, ever). But there can be other, perhaps less dark options as well. Need a good reason for one of the guards to sneak the PCs into the Fortress of Evil? Maybe they saved his uncle from an orc raid a year back, and he’s paying them back for that. Would the plot work better if one particular NPC pursued a policy beyond all rhyme or reason? Well, she must have promised her dying mother that she’d never give up, and never surrender. And so on.
As an added bonus, the general universality of family ties will give the GM an extra way to extrapolate NPC behaviors consistently. That can be helpful when you’re trying to make up something on the fly. Which happens a lot in RPGs, for some reason…