In Chapter 9, the sisters come face to face, making the rift between them very clear.
If you didn’t know which sister was meant to be the hero and which was meant to be the villain, you probably learned the difference in this chapter. Not that it wasn’t obvious before, but now, we see another side of Jill — namely, how she acts around her inferiors. She abuses the status she has, views it as her right. Jack’s conversation with the stallholder at the end makes it clear that she has acted worse than this before, and could act much worse out of jealousy. Being Jack’s friend is dangerous. We have been warned.