Good worldbuilding, good plot, great character building - the only flaw is that since nothing good ever happens to the characters, you can spot (almost) everything that's gonna happen to each character miles away.

Worldbuilding: The depiction of Slavery is very heart-wrenching. The 2 mystery elements: Serpents, and Rain Wild River Trade are also very well baked into the story.

Characters: Amazingly well done, no different from previous books.

Unsure if I'll read on to the next book immediately though.