This is for the whole series (up to book 5) not just this book, kind of.
Honestly, I WANT TO like these books. And in some ways I really do, I'll probably read the sixth one when it comes out too. I've not read other works by the author and I probably won't, largely because of these books.
The world presented in the series is compelling, lived in and fascinating. I want to know more of Aethers legend, more of the conflicts between the nations, the politics of the Empire... That said, the author gives us almost none of that, even though by and large he has ample opportunity to do so. For context - the main characters spend a huge amount of time in the library LEARNING THOSE THINGS. And yet we don't get anything but the most perfunctory of mentions. As in the MC is reading the different legends of Aether and we don't even get a glimpse, just "huh, they're all over the place, takes forever to piece what's what". So despite it being 5 books in, and as the title would suggest Aethers legends being centrepiece of the story... nope, I still know nothing. Which makes no sense considering the characters DO KNOW, even if it's just speculation. This goes for everything, really - there's a massive amount of dialogue and worldbuilding that's just not being done, even though it clearly should have been.
Now for the true offence and, largely, the reason why I even bothered to write this.
This is a harem book. NOW... I honestly have no problem with those, Jan Stryvant's "Valens Legacy" and "Valens Heritage" are some of my favourite series, hell I'm currently going through Benjamin Medrano's works (lesbian fiction) and while they're smut-free 3 of the 4 series I read are harem(ish). I don't even have a problem with the teeth rotting language the characters use (my love, my heart, dearest...), one expects a level of rainbow vomit when seeing people (probably teenagers though it's never actually mentioned how old the characters are, for all I know they're actual children) deeply in love.
The problem is the male MC. 3 books, no joke, 3 books worth of internal monologue which all boils down to him feeling bad for wanting more women in his harem. Even though, and this is why it INFURIATES ME SO... ALL his partners tell him it's OK, they know it's part of the plot (as it were), and accept it. The primary female MC even tells him SHE has certain desires regarding the others...
And yet we get chapter, after chapter, after chapter of self doubt. Now, I'm not expecting Greg to just do a 180 degree turn and become a player/horndog but there is a point where you either trust your partners and believe what they tell you (that it's OK and they want it too) or you're just an insecure twit who doesn't deserve the women in his life if you can't trust what they tell you and can't accept your own wants. And frankly it's tiring to read the same internal drama over and over again. And make no mistake, that is what's happening here, the same issue being re-hashed ad nauseum. In fact, considering accepting ones desires is a pretty significant plot point at some point I still struggle to see how he manages to pass that test, because it's (story-wise) a pretty big milestone for the characters personal development... But Greg doesn't really change. I know the MC is a country bumpkin and has no experience but still...
So, yeah. 2 stars because honestly the world is great, the characters are largely interesting and the adventure itself has great potential. But the glaring laziness of the author in actually building the world for us and the infuriating self-doubt of the main character loose those 3 stars. Especially the MC.
I'll still read the next, goddamn, book because for a Kindle Unlimited series it's kinda-sorta-OK.