I'm going to come right out and say that I don't understand the appeal of many of these "dark" stories. I've liked some, but not those that follow this formula. And it's not because Anton humiliates Grace (though that's part of it); it's not because he tortures her (though that's part of it); it's not because she's his slave (that's actually not part of it); it's not even because of the rapes (though that's part of it and "dubious permission and graphic violence" doesn't begin to cover what happens here). Rather, my fundamental objection is that this book is yet another "edgy" sex & violence tale underpinned by a deeply conservative, heteronormative ideology in which a "bad" boy is redeemed by the unwavering love and forgiveness of the "good" girl. Stop me if you've NEVER heard this trope before. I realize that I've given a spoiler, but, seriously, did you expect that this wouldn't happen?
Now, certainly this trope works: countless -- countless -- books depict it and I assume authors wouldn't write it and readers wouldn't, well, read it if they didn't like it. But, my question is: why? Leaving aside the rape- and torture-porn aspect of it (yes, it's fantasy; yes, no one is advocating for rape and torture in the real world; yes, the book itself condemns Anton's treatment of Grace), just what is interesting here? What is interesting about a woman who instantly and without his having to provide any restitution forgives a man who has treated her so abominably (indeed, he almost kills her and is shocked, shocked at her condition)? What is compelling about a plot that has so little complexity, a couple that has so little conflict, or a story arc that has so little tension because after he rapes her, places her in a small cage that dangerously cuts off her circulation, and threatens to give her to men who want to rape and cut her to death, all he has to do is say "Sorry, we good?" and she immediately and with no hesitation, says "Whatevs, dude, it's cool" -- not once, but twice! Because I like my heroines to have more grit and my narratives to not essentially end even though the book is only at the half-way mark (yes, more happens, but only so the author can include another scene of rape/torture porn), I found this storyline and the characters boring and predictable beyond belief.
Finally, here's who we're supposed invest in: multi-millionaire and multi-ethnic (or multi-species) Anton, who can't move on and decides to take revenge on a young woman who insulted him six years ago when she was sixteen. Sixteen! Let me say that again: Sixteen! Yes, Anton, because we should all hold those who said stupid things when they were teenagers responsible forevermore.
I note that many of the reviews don't like Grace, calling her a doormat -- and she is -- but Anton is, as he says, little more than "a snot-nosed schoolboy." Since I like to read about men -- not little boys -- this book wasn't for me. And I want to repeat: it's not (just) because of the "darkness" (that ridiculously vague and overused word), the rapes, the torture, the beatings, the humiliation, or the enslavement; rather, it's because I like to read about rising action, unexpected plot points, complex characters, and HEAs that aren't easily earned -- none of which are present in this book. I realize that generic readers expect certain tropes and that that familiarity is part of genre's appeal, but in far too many of these books, I just feel that I'm reading the exact same story over and over again -- only the names and planets locations have been changed.
Side Note: The Braxians' thing for bashing in the heads of their "half-breed" newborns seems like more than a minor "cultural difference." Just sayin'.