A general rule of thumb when considering creatures, NPCs, and plot hooks is to ask yourself: Does this seem like something that would fit in with a Grimm tale? Does this seem like something that would fit in with a wuxia tale? If not, then it probably doesn't belong in the setting.
Best of luck DMing! I'd love to take a look at things once you get them started.
I've been thinking a lot about the city of Span recently. I've got some very cool ideas for the dynamic of the city, and I'm excited to have a chance to explore it. That's probably what I'll be typing up in the next few weeks, so keep your eyes peeled, everyone!