RAMPANT SPOILERS THROUGHOUT, BECAUSE I REALLY DON'T FUCKING CARE 
 I went into The Merciless with no knowledge about its contents other than the vaguely-remembered buzzline of "Mean Girls meets The Exorcist", and I feel like that particular comparison implies something COMPLETELY different to me than it does to the person who wrote it. To me, "like Mean Girls" implies that there will be some meaningful insight into the adversarial relationships between teenage girls. That there will be some subversive content, some lesson learned, because that is literally the E N T I R E P O I N T of Mean Girls. THE ENTIRE POINT. 
 Consequently, I was expecting some kind of horror movie Mean Girls, something Heathers-esque, some Jennifer's Body shit. I don't think that's completely unreasonable, and in fact, I kind of feel like the first half of the book reinforced it. 
 Obviously I have no way of knowing if the impression I got was intentional or if it was just me seeing what I expected to see, but the first ~fifty pages of this book struck me as intensely self-aware, as though everything - the characters, setting, conflicts - were extremely stereotypical on purpose. Presumably because the book wanted to make sure you recognized these (awful) tropes before it deconstructed and/or subverted them. It seemed so self-aware that for a really long time, I was convinced that something clever and unexpected had to be waiting in the wings, because this book couldn't possibly be as shallow and trite as it seemed. 
 AU CONTRAIRE 
 I've run this thing through my mind backwards, forwards, and upside down, and if there is any kind of insightful commentary or allegory in there for female friendships and/or mean girls and/or bullying and shit, I'm not seeing it. Even the bare minimum morality play that you'd expect from this sort of premise - bullying is bad, stand up to peer pressure, rah rah - is completely undone by the ending, so I guess you could say that there's a subversion of the expectation that this book should have bare-minimum morals? 
 At any rate, without the presence of any meaningful deconstruction, what we're left with is the story of three stereotypical high-school alpha bitches torturing a stereotypical high-school "bad girl", while the most FRUSTRATINGLY PASSIVE HEROINE EVER waffles on whether or not to interfere, with some (ineffective) gore and horror movie jump scares thrown in for good measure. 
 So basically, a novel centered around a trope that I hate, played completely straight, taken to an infuriating extreme, for no meaningful reason and no appreciable payoff. LOL! Girls are awful sociopathic monsters that all secretly hate one another, and cut each other into ribbons over boys! Here, let me describe a fingernail being sliced off, isn't that so scary? 
 There is a twist, because of course there is, but given that there were only maybe three possible SHOCKING REVERSE-PSYCH! options, it is not, in fact, all that twisty. Turns out the girl that they're torturing for being a demon is actually a demon! Surprise! 
 The only thing the twist does is undermine any weight the novel might have had with some fucking ambiguity, and retroactively justify the cruel antics of the, again, literally torturous Alpha Bitches. The book attempts to recast the girls as victims for the last ten pages or so, as Brooklyn exacts her (kind of warranted) revenge, but it's an utterly ridiculous ask, because who could possibly care about what happens to these girls after they spent an entire night LITERALLY TORTURING SOMEONE? 
 Honestly, even post-twist, I'm still inclined to sympathize more with Actual Demon Brooklyn than any of her tormentors. Sure, she was legit a demon, but she didn't actually do anything to any of the girls except for sleep with one of their (ex)boyfriends, and Not-A-Demon-Just-Evil Riley didn't even wait for her to do that before she started plotting the extended torture session. 
 I honestly don't know why I'm supposed to have enjoyed this book at all. It goes out of its way to make its characters caricatures of human beings, piling on their cruelty, their pettiness, their selfishness, their genuine murderousness, without doing a lick to humanize them in the opposite direction. It's obviously meant to make them seem like monsters - which it does - but it also makes the story dumber, more cartoonish and less emotionally affecting on any level other than rage. 
 We're probably supposed to be invested in our heroine, Sofia, but by the time we got to the exorcism, I wanted to punch her in the face, too. I get wanting to have friends and fit in, but Sofia is dense and ineffectual in a way that I have no patience for. I mean, Riley begins their relationship by nearly drowning her in a bathroom sink, and then literally BREAKS INTO HER HOUSE AT NIGHT WHILE SHE'S SLEEPING to drag her out for a nighttime excursion. I repeat, she BREAKS INTO HER HOUSE. And Sofia is RELIEVED and GOES WITH HER. 
 WHAT??? 
 That is so absurdly far over the line for acceptable new-friend behavior that I genuinely don't understand how the book could continue after it. THAT IS SO FUCKING CREEPY. Who does that? More than that, who wouldn't IMMEDIATELY kick her out and then possibly call the cops? HOW MANY MORE WARNING SIGNS DO YOU NEED, SOFIA? 
 Sofia's characterization doesn't get any better once the exorcism actually gets underway. She and Grace - the only other character to be portrayed as something akin to an empathetic human being - are successfully kept in check by two skinny-ass teenage girls, despite the fact that I'm sure one well-timed punch or tackle could have ended Riley's reign of terror before it began. 
 There's no real rhyme or reason for why Grace or Sofia go along with this, despite generally being portrayed as decent people (up until the end, which we'll get to). Grace gets a throwaway line in the beginning about how Riley ended a campaign of racist bullying against her when she first moved to town, and how she'd "do anything for her", but assisting in the kidnapping and torture of a human being? Really? 
 The thing is, I feel like there's a completely obvious explanation for why Sofia and Grace would be hesitant to go against Riley that the book never acknowledges: they are two young women of color relatively new to a small Mississippi town that is canonically racist as shit. Seriously, even aside from the racist bullying, it's described as having "row after row of perfect suburban houses with Mississippi flags hanging from their porches." 
 Yeah, fuuuuuck that. A Mexican girl and a black girl having to live in a town with a version of the Confederate flag lining every street? I'd be terrified. I could easily imagine Grace and Sofia being weary of going against Riley and Alexis, two pretty, wealthy white girls from influential families, because they know that they could easily cry their white girl tears and point the finger at the them, quite possibly the only two brown girls in this unapologetically white-supremacist town. 
 It'd be so much easier to understand their hesitation if this angle were in any way acknowledged. The foundation is there for it, and I find that whole Mississippi flag scene - along with the discussion that follows, about how Grace and Sofia feel so much safer in the land of stars and bars than in either of the cities they came from - too fucking oblivious to be anything but intentional. Yet the book never explicitly addresses it. Grace has her line about doing anything for Riley and then largely fades into the background for the rest of the book, and Sofia's endless rationalizations never touch on any social power imbalance between them. Like the intense homoeroticism, it's another weird angle that goes nowhere. 
 Oh shit, did I not mention the intense homoeroticism? Because that's a fucking Thing. Riley and Brooklyn are really, REALLY touchy-feely with Sofia. They get up in her space constantly, and there are long, drawn-out moments of close-enough-to-kiss tension that I thought were intentional. I thought maybe there had been some angsty affair between Brooklyn and Riley, and that Riley's violence was an expression of her religiously-driven internalized homophobia. I mean, I didn't want that, necessarily, but at least it would have been SOMETHING to give this book context, to make Riley's actions make some kind of sense. 
 But it doesn't matter, because like most of the shit in this book that seems like it's going to be significant, it's not. 
 Anyway, Sofia. Even if you could get past her acting like the girl that you yell at for running up the stairs in a horror movie enough to care about her, you'd just be falling into the book's cheap trap, because she also turns out to have been a murderous demon all along. Not in any kind of fun, stabbin'-and-fuckin' way, mind you, but in a boring, agency-less sort of way, where she just alludes to some traumatic event from her past a lot, and then has a surprise last-page reveal. She's a demon-possessed murderer! But only sometimes and she feels bad about it, maybe? We have no way of knowing, because the book just drops that "bomb" and then ends. Fuck you, reader! 
 So much bullshit, and that's not even touching on how this book associates skuzzy and evil with poverty, piercings and tattoos, or how Alexis' legitimate impulse-control disorder (trichotillomania; she plucks out strands of her hair) is used as an indicator of her twisted fragility, or how difficult the action is to follow, how glitchy the continuity is between scenes, or even how SO MUCH MURDEROUS DRAMA in this book is triggered by girls fighting over a goddamn BOY. 
 Christ, this book is a clusterfuck of awful. And yes, I get that ~it's a horror book~, and that it doesn't have to have grand social commentary or moral message to be good, but a) if you're gonna center your story around girlhate, then yeah, I kind of need you to do something with that, and b) it DOES at least need to be scary, and The Merciless is not. It's more violent than I expected it to be, but the violence isn't scary, just infuriating in this context. It goes for a few tried-and-true movie creeps, but without atmosphere they're meaningless, file under "You can't just describe a scene from a horror film and expect it to be scary in a book". 
 So yeah, fuck this noise. There was nothing redeeming about The Merciless for me except its brevity.