If you think about it, this makes perfect sense. You need these NPCs to fit the world, you don’t want a medieval world filled with talk of tech and cell phones. And similarly, you can’t have a married NPC talking about how they lament being single.

Meaning the NPCs will need backstory, and honestly likely a lot of it to make sure things roll properly. They will likely also need history with other NPCs, understanding of their past to an extent, and more. And that’s just for the background characters.