Leaf joins Arthur in the House this time around, though she doesn't stay with him for very long. In his absence, though she's pretty awesome. She becomes a ship boy on a miserable ship, goes through her own losses, and does what she has to in order to survive. I kind of wish we'd gotten to see a bit more of her time on the ship, actually.
Arthur is now resigned to helping the House and defeating the Morrow Days. He still wants to stay human, but he isn't fighting against his role as the rightful heir anymore. I feel like this isn't an attitude you see often, and I admire it since it feels realistic.
I like that the books have slowly been leaking in the idea that Arthur might become a denizen if he uses too much magic. It's obviously a problem (especially since we're only on Wednesday), but it's pointed out in an obvious way. Just little bits here and there so the reader, like Arthur, doesn't quite realize how this is all changing Arthur.