Clarification: English is my second lenguage so I apology for the grammar, the spelling and/or the incorrect use of words.
First of all, this is not going to be a thorough review but more of a rant. Oh, and unexplicit spoilers ahead.
Violent dark story? Graphic depictions of horrible acts that make you want to look away? I have absolutely no problem with any of that, as some of my favorite manga include Berserk and Gantz.
So why is the biggest problem of this manga the graphic violence? Have I suddenly become a "snowflake"? Simpler thant that, it's bad done.
But I'm referring to something very specific here.
When you have a character brutally raped you are going to cause me an emotional pain of some degree. And I'm okay with that, as if I'm reading any story is because I expect to be emotionally invested and if something like that happens I'm gonna be hurt. Nothing wrong there.
Is the rape coherent with the world of the manga? Yes, it doesn't feel out of place and it's what you would expect from the grim reality of this fiction.
Is the rape motivated by something other than the tone of the story? Yes, it moves the main character to the final stage of the story by giving him a motivation, which is decent enough, although I wouldn't say necessary and some would even consider it untasteful/cheap to use it as a plot mechanism, but to me if it feels as if it was unavoidable in the world of the story, then it's okay.
Now this manga makes the rape very explicit. I have no problem with that either, if the mangaka decided to depict it that way I'm okay with it. There are other ways to make me understand much more closely what the characters are feeling, but I accept that explicity is the path you chose.
So everything is perfect by my book. You've made your point in depicting it the way you wanted it, the horryfing nature of what is happening is engraved in my mind and it served a purpose on the narrative.
But then you go on, and you go on, and you keep on going and I can't help but wonder, is this even "mature" content anymore or am I seeing porn?
Yes, at one point it became so unnecessary that it made me feel as if a rape scene was porn. "Am I supossed to be jerking off?" Is what I thought. You could say the artists were trying to be truthful to what was going on, but if that was the case the perspective was very wrong.
"Mature" my fucking ass. Rape can usually serve to stablish or reinforce the tone of a story or as a plot device, the specific case I'm referring to accomplishes the second (the tone needs no reinforcement at this point), as I previously said. But why does it keep on going for five chapters? For what fucking purpose?
Being disgusting is besides the point, it's rape, it's supossed to be. But it's badly written, and what becomes disgusting is not only the act depicted in the manga, but the manga itself.
Rape is not necessarily deep nor mature, and if you think otherwise you're very clearly immature.