The main characters were much flawed and yet you couldn't really hate them when their imperfections showed (be it their selfishness or their hatred). But then again there's something to be said about being perfectly imperfect and that's what these characters were. Nyx felt hatred and resentment which made her feel real whereas Ignifex wasn't the "tough bad guy who is a complete fuzzy bear inside". He had a very rational reason for him being the way he is and he makes no justification. He is how he is. Even the two-faced Astraia provoked such hatred in the reader that it made one relish in the lifelike aspects of the characters.
Moreover, the castle was quite interesting too with its constantly changing and befuddling nature. The inner workings of the castle were compellingly bizarre - sometimes it rained in the library and sometimes the books couldn't even be read.
However, the romance was a mess. The insta-love made me dock off a point. It was quite unrealistic when Nyx suddenly, and out of nowhere, declares her love for Shade after a breathless-and-toe-curling type of kiss. She lost a little respect from me over there. Her reasons didn't make that much of a sense honestly.
Then there was Ignifex who declared his love for Nyx and that was a whiplash. Sure, they were having nice, cute moments but these moments in no way gave the impression that Ignifex was quite there yet. It felt like the beginning of the love-path, not the conclusion, when Ignifex's love declaration was made.
Just so you know it's not a love triangle...at least it doesn't provoke the feelings that a love triangle does in a reader, but, like I said, it's a mess - a juvenile mess which could've been handled in a much better way. Though I think that the writer wanted to make the reader realize that Nyx loved both sides of Marcus Valerius Lux but it just ended up being frustratingly confusing when at the end there was this 'time dismantling and renewing itself' and then...they said...that they will "pretend" to be in love until they finally do fall in love?? Uh, what?
I get that they're new people now but seriously? ----SPOILER----You still got your memories back from the other time and you are bargaining to sacrifice yourself because you're in love with the guy...but then you say you need to pretend?----SPOILER ENDS---- Quite the paradox.
With that said, the book was overall enjoyable!