They can introduce you to the circus quest in case you speak to them before speaking to the guard. Otherwise, they're just random background characters to make the city look more alive. I also like that they are from Trademeet.
I think that the Harolds also occur in BG1, so they are in some ways the continuation of characters between the two games, but apart from that they're just there for a bit of fun.
I'm bumping this because apparently the poor couple can't catch a break! If you go back to the promenade at night, Mrs Harrold is missing. Perhaps eaten by vampires?
Comments
What happened to Ms. Harrold ...
> Perhaps eaten by vampires?
That - or perhaps she is out with another man!
Or it could be an attractive vampire male.