The most often overlooked aspect of roleplaying (this is just a guess, I don’t have any research or raw data to back this up) are the parts of the game the players seldom, if ever, dig into. Non-Player Characters are treated by most players as expendable pawns in a chess game in which the players deem only themselves worthy to play in. So underneath the primary plot lines that keep players jumping from one tempestuous problem to another there lie the deeper and more enigmatic subplots that motivate the lowly and oft ignored NPCs.
Not every NPC has a deeply enriching tale to tell, of course. A Game Master has to juggle a lot of NPCs and unless they have all of the free time in the world there is no feasible way to make all of them super interesting and worthy of their own book deals. But this is why the game doesn’t hurtle along like a rocket sled full of dynamite. Taking the game a little slowly helps to develop the story and that by necessity means fleshing out the NPCs a little better and more naturally. Hinging of course on the players ever taking notice of the NPCs in their midst in the first place.
But let’s say for the sake of argument that the players are oblivious to the machinations of their minions, henchmen, hirelings, and followers. Maybe the primary plots are simply too fascinating for the players to turn their attention briefly to pondering the backstory of a particular NPC. Not all players are inclined to spend a game session sneaking around trying to find out who exactly a trusted NPC really is, where they came from, and what secrets they might have tucked away in their skeleton-filled closet. This is actually ideal from the point of view of moving the story along. When players miss the cues given by the GM it can always be farmed out to an NPC to quietly follow up and let the players know that they might have dropped the ball. And why and how the NPC does this is up to the GM. Perhaps the NPC in question has a background in criminal investigations that the players never inquired about. Maybe they were a detective, or perhaps they are versed in the law from having broken it repeatedly themselves. Either way the NPC is able to help the players out and the less they question how the NPC was able to discern the clues the more the GM can embellish the NPC’s backstory to make them even more interesting once the players get around to asking.
Now, not every player or even every group of players is going to care what the NPC does so long as the players gain wealth and fame. This means that the NPCs attached to the players might well be ignored. And that opens up an even more delicious avenue for the GM; subplots that feed the main plots but that the players never figure out because the NPCs are the ones feeding the subplots. As long as the players are in the dark the GM can run circles around them with schemes and plots and adventures. The main storyline villains can have an absolute heyday while the NPCs quietly run amok with their own adventures. This can continue without ending as long as the players remain focused on their own goals. The NPCs meanwhile begin carving a bigger and bigger chunk out of the gaming world for themselves and eventually, if the players haven’t paid attention to any of this, become power brokers and maybe even villains in their own right.
All GMs have their favorite NPCs. I naturally have mine. And releasing them into the gaming world to make their own marks has its own rewards. Even more rewarding is when nobody notices.