Manga Far more interesting than expected
I agree with the below reviewer that there is no reason why any normal person would enjoy this. Normal people tend to prefer safe and predictable things that make them feel safe and predictable emotions. But for those of you who like to have the boundaries of your emotions stretched into new and often uncomfortable shapes then this is a manga worth investing in.
At it's heart it is a tale of finding humanity and while that is not alone worthy of note one of the strongest points is that the villains progress from emotionless psychopath to feeling psychopath to finally an incredibly evil but recognizable human being is almost as, if not more interesting than the protagonists journey from scornful and aloof to desperate and vulnerable.
At times it skips over the line from borderline pornographic to pornographic, but the context is always disturbing enough that it leaves a distateful sheen on your tongue. I suspect that this is part of the intent but either way, expect that you are going to see alot of shit that is going to make you deeply uncomfortable and not only in the category of sex but in terms of violence as well. Bad bad things happen to people and not all of them really deserve it.
Also, despite the often trasgressive content the moral questions and philosphical debates posed by the series are relatively complex. For more adult than many works of ostentibly greater maturity. Especially interesting are the questions that it frames about non violent resistance and the insidious nature of pride.
A final time I would just advise people that if you are the sort of person who has ever put down a book, comic or movie in disgust, not because you thought it was bad, or that it had some message that you found unpleasent, but because it was simply unbearable to continue, this is most certainly not the manga for you. However if you are the sort of person who read and enjoyed works like Berserk or the First Law Trilogy then you might find that there is something worthwhile.
Manga Why?
I cannot see why any normal person would read this manga. Rape and violence abound, and everyone is either a jerkass, a Complete Monster, or stupid and useless (and boring). Or fanservice/Estrogen Brigade Bait. The violence doesn't really provoke any reaction, it's typically Inugami just standing there, taking crap (beating, hit by a car, he does get shot once). I originally used "enduring" instead of "taking", but he doesn't even do that. You can't feel anything for Inugami when getting run over by a car is a walk in the park for him.
Related to that point, I can appreciate a "soul-crushing" story if the characters are compelling, if a Trauma Conga Line is necessary for satisfying character growth, but I'm 75 chapters in and there isn't any catharsis. Inugami just goes further down the angst-hole, while Haguro, I think, has the more interesting transformations.
That's not even going into my main problem with this Crapsack World series, which is that all of this is taking place in a high school setting. We have an insanely strong werewolf protagonist, a very capable, frightening villain, a few interesting moments of insight (I am not counting anvilicious wolf worship as interesting), so why did it have to be a Darker And Edgier High School Drama?
If you are prone to Darkness Induced Audience Apathy, don't read this.
Edit: The series has lately moved away from the high school setting and more towards "let's try to break Aoshika so Inugami can save her and they'll have twu wuv". I don't consider this an improvement. In hindsight, this manga uses Aoshika and the other female characters really exploitatively. But mostly Aoshika. When the manga's not being boring and trite, it's being disgusting.
Manga Waste of decent lore
As soon as Inugami stops being bullied as school is when you should stop reading. The manga has a nice lore going on. The doom on all werewolves, the immortality during the days around the full moon, the general inheritance of power. The problem is that it's buried under what can be described as a slideshow of everything wrong with human nature.
The author apparently thought rape was a good thing to show over the course of at least 25 chapters. Then again there's the insanity of Haguro. If that character did not exist the manga would not have been so bad. The glaring lack of logic to him just ruins the story outright. No justification is given for his desire to kill the main character. They're all paper thin excuses to get him to antagonize the hero. None of the characters are really used very well, most are just there for window dressing!
Honestly there are better werewolf stories out there. Bisclavret and the Astounding Wolf man tell better thought out stories than this garbage.