While I don't mind having multiple POVs for a book, I didn't like the way it was structured here.  Pretty much any important character was up for grabs as long it would give a POV that would let a section of the plot progress.  Because of that the book felt a bit scattered and frantic since we were jumping around so much.

Also, if I can make a Frozen reference, one thing I loathe about the beginning of that movie is the Anna/Hans romance "development".  Pretty much all the relationships here are like that.  "We've just met...let's get married."  (I wish I were joking about how long it goes from meeting -> proposal.)

The world with the different countries and the magic was interesting.  I'd like to see that fleshed out a bit more other than the people focusing on the metal magic.

The marriage of Leah and what went on in that household after she arrived was very disturbing.

Burning her at the dinner table for asking questions/speaking back, welding a metal collar on her so that it could be heated up if she "misbehaved", her husband smacking her whenever the grandmother would indicate she needed to be punished, her "inspection" after suspected pregnancy by the grandmother and with the brothers in the room watching her strip naked, the brother-in-law deciding he would be the one to consummate the marriage because he wanted to, etc.

It was a very uncomfortable section of the book and I was upset that she returned.  I never actually liked Leah as a character, but even then I didn't like her in that environment.

Naia was an easier character for me to get attached to, but she seems to have dumped her brain out the moving carriage on the way to the meeting of the nobles at the beginning of the book.  Her life decisions are motivated by pretty eyes and the memory of a kiss.  Alright, if I'm being fair she's also trying to get a bit of freedom, but I just can't get on board with the dumbness that enters her brain to do it.

Fel, I really liked.  He's a man of great magical power and didn't let his disability hold him back.  He does have an annoyingly long mope timeframe though.

River, I don't like because he pretty much imprisons Naia because of devotion and safety, but also doesn't communicate anything.  He says he loves her, and I know he's young, but he clearly doesn't respect her enough to talk to her after he's corrected about whether or not she tried to kill him on their first meeting.

Also, I don't know if it was just the digital version, but the book needs to go to a proofreader with the number of typos and partial sentences I encountered.  It wasn't enough to make the book unreadable, but it did have me wondering if English wasn't the native language of the writer or if the writer was young.

I'm not interested in the characters enough to want to see how the story continues so I'll be stopping here.  It's definitely a book world and plot that I wouldn't mind re-reading if it went through another rounding of editing with a publisher that could tighten up the flow a bit more.