Very horny for YA. 
I agree with the other reviews, "Dark Heir" suffers from being the second book in (I think) a trilogy.

There are more plot holes than I found tolerable and a whole lot of characters who serve no other purpose than to help our heroes and die immediately after. 
Visander and Philip intrigued me, but I felt both were left unexplored by the narrative.
Elizabeth is still one of my favourites, delightfully written to be a child whilst still very clever.
Cyprian was sweet, I loved his development but I was still left wanting more.
Violet, I truly don't understand why she had the subplot she did.

I adore her, more than Will probably so it was so frustrating having her be reduced to a C plot that was quite literally happening in another country. I felt like she disappeared for the first 40%. And I like all the ideas the C plot brought up like her mom and Tom, most of the time she would be absent for long chunks in the book I would forget what had last happened when we were with her. But her chapters were usually after some cliffhanger in the A or B plot so in comparison her brief imprisonment felt irrelevant

I felt enraged on James's behalf

I had accidentally spoiled the fact that he ends this book with the collar so I was dreading it, I really dislike the creepy implications and I'm really hoping he ends the series free from it.

Also, shout out to Will for being simply the worst at communicating I'm sure you're friends would've believed in you if you tried a little harder to not sound evil ❤.

That ending has left me unwell.

There is such a huge difference in pacing between the first book and this one. I was engaged throughout, and across all the different perspectives, which doesn't happen that often.

The highlights of this book are definitely Will and James, aka Sarcean and Anharion. Their dynamic just hit all my buttons. I have 62 highlights on Kindle, and I'm sure that 80% are related to these two. And it's complex, too, because is this really a romance, considering all the things we know as the reader, that James isn't privy to? And yet it feels like one. It's such a slow burn between them, with so many good moments and quotes. I also feel like there's still more to discover about their relationship in the past, that not all is as it seems there.

All in all, I really appreciate what Pacat is doing with this story, and I'm so excited to find out how it concludes.