Fleshing Out NPCs

Chris Perkins says it better than I could, in his new article on 3D NPCs.  I would love to play in one of his campaigns!  Anyways, I'd highly suggest anyone who DMs read this article.

In particular, I'd like to highlight the parallel between an ongoing D&D campaign and a serialized TV show.  Obviously with the PCs being the main characters a lot of the complex relationships will grow organically as the players interact amongst each other, thus making the comparison a lot less daunting for DMs!  However, DMs still must think about this since the PCs aren't the only people populating the campaign world.  Each "adventure" should feature at least a few fleshed out NPCs (more than just background NPCs, like the random shopkeeper or barmaid), and you should have a vague idea of these characters' personalities, motivations, and backstories.  This obviously doesn't need to be too in-depth, but at least summarize each of these 3 traits in a sentence or 2.  It doesn't have to be elaborate either; most NPCs are much more mundane than the Heroes! 

For example, let's look at one of the main NPCs from my Talamhlar campaign, Gaknar (this campaign ended prematurely when I moved away for a seasonal job, and due to the months that passed before I came home we just never resumed it).  To re-cap, that campaign started with the PCs captured in a castle, regaining consciousness with the place in chaos.  A group of mages were doing various arcane experiments in the castle, including the creation of super-soldiers.  Not surprisingly, the mages lost control of the super-soldiers, were largely massacred, and the magical containment was broken, freeing the PCs.  In the room their was also a goblin named Gaknar, and he promised to show the PCs to where their equipment was and how to get out of the castle if they freed him (he'd been a servant for the mages).  He accompanied the PCs throughout the campaign, becoming a valued member of the party (well, most of the PCs liked him).  There were a few times where he acted somewhat suspiciously and was caught lying, and so was never 100% trusted.  He even disappeared "on business" once, refusing to tell the PCs what the business was.  So what was the deal with Gaknar, and what ideas did I have floating around in my head for him?

• Backstory:  Gaknar was a runt in his tribe, always picked on for it, and some semblance of a conscience (moreso than most goblins, anyways) didn't help matters.  During a raid he left his tribe, but finding it difficult to fend for himself ended up working for the mages.
• Personality:  Sycophantic, and has quirky ways of showing affection.  Sly and sneaky like most goblins, but with a greater sense of loyalty.
• Motivations/Secret:  On his errands away from the mage's castle, Gaknar began to see what life was like in the civilized worlds.  He became a spy for someone in the nearby town of Marblemount, helping to gather info on the mages to help shut them down.

Gaknar's secret never got a chance to be revealed in-game, and in fact I hadn't even fleshed out who he would be working for in Marblemount, what their exact goal was, or even whether it was a single person or an organization.  I didn't need those details until an opportunity arose for me to incorporate them into the game, and they would ultimately depend on what direction the campaign was headed.  I didn't plan on when that might be, but for things like that you just sort of know when the time is right.  I just really liked the idea of a goblin double-agent traveling with the PCs, who was ostensibly good but with a shadow of doubt.  And that concept came built in with a possible future story hook for later, even if I didn't know what that hook would be.