I have the same complaints about presentation as for the first book, however this one has the etymology and meanings of some of the proper nouns in the pronunciation guide, which is great.  Unfortunately I was unable to maintain this optimism about the actual narrative. 

Generally every aspect of this book (plot, characters and setting) is more original than Book 1, due to no longer being so tightly shackled to the inspirational source material of AtLA and ACOTAR (and to a lesser extent, ASOIAF and Shadow and Bone). 

The idea of this book is great - dead or missing mothers are one of the most ubiquitous tropes in fantasy, and it's quite rare for the mother to be given any sort of complex characterisation or history. Particularly in the case of male heroes, the dead/absent mother is usually written as an archetypal, perfectly idealised goddess-figure for the hero to mourn and/or avenge. The mother's suffering at the hands of Men might also be used as the motivation for the hero to declare himself a feminist in a traditionally chauvinist culture (or more transparently, as an excuse to allow author to write the love interest as a feminist, thus making him dreamy). 

In the first book, our hero Kell was modeled after Zuko (yay) and Rhysand (boo, hiss), both of whom had mothers who were sacrificed by the writers at the altar of male protagonist man-pain.  I only made it 2 books into ACOTAR, but I remember thinking in the second book that Rhysand's mother was given an unusual amount of attention in the Illyrian backstory infodump and I expected to hear more about her experiences later in the story, but I am told this doesn't happen. Zuko's mother is believed to be dead until about halfway through the final season, and after she is revealed to be (possibly) alive, nothing more comes of it and this revelation doesn't have any strong influence on Zuko's characterisation in any subsequent episode (we do not acknowledge the AtLA comics in this house). 

So this idea of writing a full-length sequel/prequel where the former protagonist's absent mother is the main character is neat. Moreover, Annick is a Bad Mother who hates her eldest son for reminding her of his evil father.

Unfortunately, however, writing believable ancient immortal non-human characters (let alone in first person POV) is very difficult to do, and so 900 year old faerie queen Annick might have been an overly ambitious protagonist for a relatively inexperienced author (Annick is convincingly neither ancient nor inhuman), but Elizabeth did at least succeed in making Annick's narrative voice more mature and worldly than Rosalie's was.

The setting is also beginning to feel very artificial (like a backdrop for a play rather than a fully realised world), as we are two books in and we have learned very, very little about the lives, cultures and beliefs of the common people who inhabit these kingdoms - all of the main characters are royals or royal guards/spies/advisors, and the action rarely strays outside the walls of various castles and palaces. 

Bizarrely, in this novel which is backstory about Kell's conception, the "romance" feels very out of place. "Romance" is in scare quotes because it isn't, really - Annick has lustful sex with the king while she is still grieving the deaths of her former lovers, and then we are told that they are falling in love (and of course they are mates, which is a concept that is given far less explanation and plot-relevance than it is in the SJM-verse, and makes no sense because the king is a human), but they have had hardly any on-page interactions by the time they are “in love”, and most of those interactions are in council meetings. The romance really suffered from not being explored through both POVs, and by the end of the book, I still couldn’t identify any of King Henry’s distinguishing character traits other than his bedroom preferences, which I would prefer to know far less about. Probably the worst indictment I can give this book is that I was not even slightly bothered when Henry died at the end, because I didn't believe in the "love story" in the first place, and now book 3 can (hopefully) have an actually interesting plot about actually interesting characters.