Often when you complete a quest, you can go back to the NPCs later and continue the conversation.
A prime example is Rattigan after the “Rats and Raiders” quest is completed, who you can find elsewhere (no spoilers).
It adds so much richness to the story and absolutely love it. It’s been missing from many games for decades and I encourage the Devs to continue doing this as more content is added.
Some NPCs show up in town after certain events too, the guy who is praying before the Darak sewer fight can be found next to the house you can buy near the cemetery, and theres a woman near the shrine to the old gods in town that gives us a backstory into Darak.
Another one i found were the guards that were guarding the prisioners, you steal the key, and they end up near the entrance to the slums, where that beggar with the dog is.
Awesome, I’ve seen the demoted guards in the slums and that was great.
The guy praying I didnt know about. He’s the one who’s stuck on that tree ? I presumed he died because he wasn’t there when I went back. I will have to search for him.
I think I did talk to the woman about Darak, who tells you about the woman he is trying to ‘protect’ in the voice-overs while you explore the sewers.