Fire by Kristin Cashore is a prequel (sort of) to Graceling for the inclusion of Leck. If you remove him, it pretty much stands alone. Frankly, I would have liked it better had it been written as a stand alone because the rules of the world seem to be completely different.
In the Dells there are apparently monster versions of all living creatures. These things are strikingly beautiful, albeit unusual looking, and often dangerous. If it had been made clear how monsters relate to gracelings (maybe a Dell word for the phenomena, or a proto-graceling state) within the first few chapters of the book, I wouldn't be annoyed. But the "just 'cuz" coming on the heals of a book with damn fine world building, just doesn't cut it.
Fire, the titular character is the last of the human monsters. She is, like Katsa is of noble birth. She's also endowed with special abilities and has hair the color of fire. And oh yeah, when she's menstruating, the entire world goes nuts and she needs an umpty bazillion body guards to keep her safe. And that's mentioned OVER AND OVER AND OVER.
Somewhere in all this mess is also a political intrigue story of young King Nash trying to hold the throne after his father and Fire's father basically gutted the kingdom on a years' long bender of sex and drugs. Except I didn't get that far. I grew bored with Fire moaning about how hard it is to be beautiful and how hard it is to manage her sex life.