It seems like there are a lot of problems with this book but they ultimately boil all down to two major issues.

First, everything moves way too fast. The main plot of this book could've easily filled 3 books.
More sub-plot with the purpose of character- and relationship-building, as well as more subtle world-building, would've been necessary of course. But by taking the time to properly develop individual aspects of the characters, their development, and their relationships, things wouldn't be so horrendously mixed up.

I had no time to adjust to anything. The MC's entire character development was way too fast. One moment she was an angel and the next she has deep feelings towards 4 uber-powerful daemons/Nephilim without even a typical harem setup, has designs on literally killing satan as well as archangel Gabriel, and completely got over her inhibitions and conditioning to be virtuous according to Christianity.

I think the second major problem is just a result of the incredibly rushed nature of the story but it could be a separate issue.
Things are so mixed as well as messed up.

This is particularly noticeable with the fucked up morality and inconsistent atmosphere.
On one hand, the story goes for a rather dark vibe. The story takes place in literal hell after all and the MC immediately ends up in an arena where she has to fight to the death for the daemon's amusement and her main motivator is revenge. But literally in the same scene, the story tries to play the sympathy card with a small demon child that is supposed to convince us they are not much different than humans and worth of love and compassion. I think this is a pretty decent example of how mental the idea of morality in this book is.

I've read other books that encompass both concepts without them contradicting so horribly.
Show us the bad and how the hard-edged MC deals with it. Show us how she can be hard and merciless if necessary. Show us her backbone and strength.
And then show her soft side, her compassion, and altruism in separate scenes with their own atmosphere and context.

And even more importantly, if you want a dark atmosphere you have to give up on your virtuous protagonists. You have to stop justifying every questionable action to the reader. Grey characters aren't grey because you insert some brutal and bloody scene here and there. Grey comes from the characters themselves struggling with right and wrong or being in violation of doing the "right" thing but having motivations the reader can sympathize with. The best grey characters are the ones where the reader starts to question his own judgment over right and wrong or starts justifying obviously wrong actions to himself without being nudged by the book. None of these concepts are explored in this book. The MC basically is always righteous and good; in hell; while killing people in an arena for entertainment; but it's fine because the opponents are bad people or monsters; because they taunted and insulted her which obviously means they deserve death.

If you want an MC that revels in fights to the death you have to slowly introduce it over time. How she goes from fear and disgust to increasingly glorying in her victories and the approval. How her moral landscape shifts. Have the readers move with her but have the morality always on the edge to uncomfortable.

A rather minor complaint in the grand scheme of things I nonetheless want to mention because I see it so often and it always annoys me is the sudden damsel in distress syndrome. We have a strong MC that grows even more powerful which from time to time suddenly is somehow completely helpless against some no-name adversary and has to be rescued by her big strong males. If you really want the damsel scenes, you have to establish beforehand that the adversary is strong/stronger than her. It just seems fake and cheap and is not worth the "male saves the heroine" moment otherwise and just calls the supposed toughness of the MC into question unnecessarily.

In conclusion, this is another case of: I see all the building blocks and what the author was going for but she utterly failed at assembling it all into a consistent story.

There was a story in there that I would've loved but it was not the one I read.

I might check out the second book to sate my curiosity if I can borrow it but I am not going to spend more money on this series.
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