Gaming

I'm not sure if my approach would work for everyone, but I like to have a strong faction leader so I can clearly define their character and think of them like I would think of my own PC. If I have a solid understanding of their motivation, their personality, how smart they are and how they deal with conflict, I can determine how they'd react to moving and shaking in their sphere of influence. A warlord might bristle at the slightest insult, or perceived insult, and be ready to settle a dispute with fists rather than even entertain diplomacy. Depending on which faction he's picking a fight with, they might ignore his posturing, get intimidated and back down, or try and goad him into doing something stupid.

Other members of a given faction will tend to reflect the leader's personality, since realistically, that's the sort of follower a strong leader often attracts: imitators. It's a bit of a shortcut so I don't have to create 50 different NPCs that the party may or may not ever meet, but still. I also think that when AI chatbots get a bit more sophisticated, I could use those to literally simulate conversations with characters I design.