Making interesting NPCs is one of the most rewarding, yet difficult jobs the DM has. IMO the biggest difference between a good and bad campaign is in the characters that populate it – fail to produce and properly play good NPCs and no amount of skill in other departments will help make your sessions into successes. Stand-alone adventure are perhaps less reliant on good NPCs, but only to a certain degree.

I'm sure there are lots of different ways to make good NPCs. I use several techniques myself, but there are always a couple of ground rules that I use.

The first is that the character needs to be different and instantly recognizable, has to project some sort of image, bordering on caricature. Why? Because most NPCs only get to shine very briefly – they don't even get fifteen minutes. If you want your players to take them seriously, even remember them for years afterward, you only got one good shot at making them stick. So I always try to make up such an unique 'image' for all my NPCs. Or at least the major ones – I tend to cheat with lesser characters, reusing older characters with only a slight twist or using NPCs from other games anew (but please don't tell).

The second is visualization. A picture is worth a lot of words and all that. It's true. So I usually try to find a fitting picture for the character on the net (there is a lot out there these days, so I'm usually only limited by the time I have available for searching). But visualization doesn't need to be just a picture – internal visualization is just as effective. Describe a character so that the players will immediately associate it with some well-known movie or other character.

The third one is; lay down a foundation, but don't build the entire house in one day. You need to develop at last a rudimentary background, personality and motivation to properly play a character, but you should not fill in all the holes. Firstly it's a waste of time if the NPC doesn't feature much after all (he might be ignored or killed or whatever – and you don't want to 'force' an NPC on the players in an unnatural fashion). Secondly you cannot predict how the character evolves once you start playing him. Once he starts 'living' in the game world things will come naturally to you. One final thing – it's OK to change stuff once you've started playing, as long as you don't do it in obvious ways! Maybe his motivations turned out not to fit – just change them, except if that would interfere with how you've played him so far or what the PCs know.

There are more rules, but they are more like guidelines anyway, so we can take them later...

Instead I'll do a few example from my Dark Heresy game. WH 40K lends itself well to ripping off stuff and caricature. So I decided to play with that a little. Take Ignace the gunslinger for example. He's based on the main character of the movie 'Equilibrium', which contains a lot of neat close-up pistol work, tweaked by giving him a some psychic powers thematically tied to the Equilibrium imagery (he can twist time and space for some really amazing gun and movement stunts).

Two guns, just like Ignace

For imagery I went with a 'bald Asian guy with Asian ninja chick girlfriend' and then added a mutation on top that makes his hair come out, only his 'hair' is actually more like razor-sharp porcupine needles. Should not be too hard to visualize.

I'm Asian too!

For background I went with 'fell in love with Asian ninja chick, ran away from evil ninja clan, and kept running until recruited into the Inquisition' – a type of background which is actually possible to create using my EXCELLENT new character path system for Dark Heresy :-P Once again easy to communicate to players and one that will be remembered – even if it's really bollocks!

We want out hot ninja chick back! No one does f1tish stiletto boots like her!

His personality was initially based upon a combination of cocky Han Solo and a grim Eastwood from some nameless spaghetti, but as it turned out he ended up rather more the former and less the later.

Don't Get Cocky, Chaos Scum!

This might sound a little cartoonish – but it actually works pretty well in play. And he does of course have his daemons to add to his personality...all my NPC have, but that's another story folks!