Wonderful manga. I think pretty misunderstood, though. A lot of people seem to think that the characters are shallow, the plot is edgy, and that the MC has no redeeming qualities or that her situation and mental health issues do not acquit her of her actions. I would know, since I'm one of them! I think people make the mistake of making the assumption that because all these things are true the manga itself is objectively "bad", which is where I have to disagree. A story might not follow the usual conventions (yes, even conventions that we define as being marks of quality) and can still be excellent and worth a read.
Let's back up a bit, right to the beginning. The mangaka was once a high school girl. She is also a victim of bullying, a survivor of rape, and suffers from depression, anxiety and other disorders. Am I saying that by criticizing this manga you're therefore being pointlessly mean to a rape survivor? No, that would be ridiculous. But the author does have personal experience with all of the phenomena this manga explores, and I think that's an important point to raise. This is not a pointlessly edgy work dedicated only to fueling the author's misanthropic hate boner, it is a dramatization of the author's personal experience that serves both to illuminate the reader to this part of society they may not otherwise be exposed to, and as a cathartic medium for the author herself.
So first, let's address criticisms people level at the main character, Kaede. Yes, to put it likely, she's a bit of a cunt. She's selfish and a lot of the actions she takes are downright illogical. To this, I would say that humans generally aren't completely logical. We are emotional and moody creatures, who may overreact and do terrible things in the interest of ourselves and our emotions. To this end, I think people are confusing agreeing with her actions with just following her twisted chain of logic. A prime example: Ichikawa's rape. Is having your bully brutally raped a reasonable escalation or punishment? Absolutely not. We should remember here that the author is a survivor of rape herself; Kaede's actions here then serve to show us how truly awful the abuse she suffers at the hands of Ichikawa and her clique makes her feel in a manner that's very powerful and enlightening if you give it the chance. Kaede's treatment of Ichikawa is, in fact, the worst thing that the author can possibly imagine being done to someone. Again, not a reasonable response, but give it the chance and it helps you understand where the author is coming from when imagining how she felt suffering through bullying.
In that same vein, one might also point out that being bullied, having a cold home life and various mental disorders do not excuse what a cold manipulative bitch Kaede quickly becomes. Of course, they'd be right: Even the author is quick to acknowledge this, with her singular interaction with "normal" girls in her class still leaving her unable to apologize to Tomiko due to her own weak willpower when compared with the social pressures exerted by Runa and Riko. The ultimate explanation for her actions is her own weak willpower and unwillingness to seek professional help, and yet her past is still an important explanation, not excuse, for her actions. She has lived a life of neglect, both from classmates and her own family. Lacking the will and support to overcome, she can merely persist in desperately attempting to uphold her social position and cling to any source of positive attention she can find, in the same way that the author must have.
Kaede isn't a likeable person. She will not grow into a well-adjusted adult, and you shouldn't be expecting that after seeing how the story will end in the very first chapter. This is a tragedy where all characters involved are trapped, either by their own unwillingness to seek help, the pressures of their local social groups, or both. In service of illustrating the world the author grew up in, though, I think that's a reasonable deviation from generally accepted conventions: The popular girls are shallow characters because, really, would you expect the people who enforce this sort of social hierarchy to be complicated, deep individuals? Of course not, that would be absurd. There's not much room for depth in people who desperately cling to popularity, their motivations are as shallow in real life as Kaede and her friends are in the manga. The author, being familiar with bullying and the pressures of social life in highschool, undoubtedly knows this and is attempting to illustrate this through her work. Sure, they've got their demons, everyone does; But in the end, they're cunts just because they're cunts, not because these children somehow possess backgrounds so morally complicated that their writers would be liable for an Oscar. In short, this is a brutally honest examination of one person's unfortunate high school experience, and it deviating heavily from normal standards of character depth are acceptable considering that IRL drama doesn't really reflect that. The author even makes use of this dissonance between what we've come to expect of the genre and what actually happens in reality, as the stock clueless yet loveable shoujo romcom protagonist Hiroshi is juxtaposed with the manipulative Kaede in a way that's downright hilarious: The moe-style singular panels which seem completely out of place with the absurdly detailed and disturbing faces the author draws through the rest of her work, and how the standard romcom beats are played through in an almost sinister manner. All of this serves to highlight not the shallowness of the manga, but how shallow and absurd these ideals really are when young people use them as a lens to view society. They are nothing but a thin wallpaper that desperately tries to hide reality to the author.
This manga's strength is its unflinching depiction of the reality of some very unfortunate people. No punches are pulled. Characters are almost pointlessly cruel to satisfy their own egos and desperately maintain their own social positions, just as humans can be emotional and cruel beyond logic in real life. The way the author depicts Kaede's social anxiety and desperate need for positive attention resonated with me deeply, as almost every instance of this in the manga is uncannily similar to my own experiences with these emotions. It is wonderful to know that you aren't alone in your feelings, and to be able to explore them through different forms of media. This is more of a docu-drama in manga form than a traditionally told story. As such, what you get out of it will really depend on what you like in a manga. If you don't want to experience the heavy personal life story of the author (and I really don't blame you) then this manga is not for you. But please, don't write it off just because the non-traditional structure didn't resonate with you. No, its not deep. But life is also pretty shallow.
I could go on about all the little nuances I noticed, from Kaede's skewed worries over Narumi to the ease with which she parts with her prostitution money, but this post is already long enough. This manga is an easy 10/10 for me, but I keep wholesome stuff on deck as a palate cleanser whenever I return for a re-read.