Fukushuu Kyoushitsu

By the seventh volume everyone is marked (dead or otherwise, as not everyone actually dies when they've been hit with Ayana's revenge) except for Mao, Miho, Ayana, Ai, Maki, Shiori, and Ryou.

The page that reviewed was translated as saying "Masori was the mastermind [behind the bullying]." Since no one is actually named Masori, I knew that was an error in the translation. So I got the 'marking' page from vol 7 in raw form and tried to match the japanese texts. 

"いじめの原因はクラスメイトの真莉が首謀者でした。"

Because I can't recognize these characters for the death of me, I just put that standalone sentence into google translate again (lol) and then tried to single out the characters/words to really check that the following was correct:

Apparently, Masori was actually supposed to be MAKI, as in, Maki was the mastermind behind all the bullying.

But that isn't the end of this ordeal. The next confusing part was this

真莉の父親は彩菜の父親のせいで自分の父親が自殺しており、それが原因で彩菜を逆恨みする。Then 娘の彩菜を追い込むことで自分の父親を死に追いやった藤沢総一郎に復讐しようと考えていた。

Which google said it was "My father 's father is a father of Aya' s father, his father committed suicide, which causes a grudge against Saika. I was planning to get revenge on Fujisawa Souichiro who pursued my father's death by driving my daughter's aya." 

I believe this is supposed to be saying that Maki and Ayana are actually COUSINS? And because Ayana's father caused Maki's father to commit, Maki is going to get revenge. It would explain her living alone, and we saw Maki had a memorial in her apartment for a man we didn't know

Apparently Miho knew about this, but was forced to go along with Maki.

Miho then had Maki come to a room in the school, only for Miho to be found dead. She wanted to get Maki, Shiori, and Mao, the main people who bullied Ayana, arrested for murder. I think this makes sense since Maki wasn't actually friends with Miho.

She apparently had used call logs as proof, she sent them to Ayana, it's damning evidence against Maki. Unimportant, but at the end of her message to the girls, she said 「ザマアミロ」which I thought was interesting, google didn't know what the fuck it meant and neither did I. According to a google translation of a yahoo ask asking the same thing, it's like "sucks to be you" ? (lol)

Shiori and Mao want to dip if what Miho is saying is true, but Maki doesn't want to go because "I am not bad! Defeat evil, avenge the father's enemy! I am right! I should punish Aya Fujisawa!"

They go to look for Ayana and Mao finds her, only for Ayana to hit Mao on the head with a mop because Miho is dead. 

when Ayana saw Ai she told her "You can escape as it is, you can escape, please do not show up in front of me again"

Now, according to the review, Ayana is in a direct confrontation with Maki " "I will not forgive [you]! Fujisawa Shinichiro [Ayana's father] will also let you know ... [the] despair to lose important people!""

Ayana get's Maki in mount position and stabs her in the thigh (translation is weird, I suggest confirming this in the raws if you really want...) (also, she has a knife..? I'm guessing the bullies were going to kill her.)

Ayana then said "I shouldn't have been born, even if I die he won't be sad"

Ayana then calls the police, saying she will explain everything. Maki is like "what the fuck is wrong with you? Everyone died because of you." but Ayana said she will confess her sins and receive punishment. It's better to receive punishment than to die when she was able to do this[revenge] (????) "I will not run way from my revenge" and stabs Maki in the chest (???????) "I will be ruined, and so will you."

As for what happened to Shouta, Ai killed him apparently, out of her love for Ayana. She broke through the school window near the stairs, but falls (and falls down the stairs) and is stabbed in the neck by a glass shard and dies.

This shocks Ayana and she goes unconcious. She's in a hospital now.

Media grabs attention of the case and calls it the "Revenge Classroom Incident", resolves that it was about the victim of bullying, Ayana, who is also a suspect in everything. (Google translates Ayana as "Saya" here, which is weird because Saya is the name of the woman in the photo with Ayana's father who he assuringly cheated with, that looks a lot like Miho)

Ren visited Ayana when she was unconcious.

Apparently, apparently, Ren was thinking about Ayana's sake when he was bullying her? Ren was talking to Yuuya outside of the hospital (room?) (because yuuya ISN'T dead) about the future  "Just being a student in Hakusaki for the past month, or being trapped by the press ... I could not get out ..." that the press was sniffing, after the other classmates survived.

I guess something also happened to Yuuki Abe and Rino Wagatsuki in volumes 5 or 6, because they also moved to the hospital, and Yuuki Abe was having rehabilitation with an artificial leg. 

While talking, Ren says "Yuuya Yamase, what do you think, no ... Fujisawa Yuya",

meaning, 

Yuuya is actually Ayana's half brother, from her father's side. Yuuya's mother is Saya Yamase, the woman in the picture with their [Ayana's] father. 

"There are two revenge plays, some who are dominating over that game board, who is the boss who started the game, and they are constantly keeping both of them" hitting the worst one "at all times. "

Basically, it's Yuuya who was the mastermind behind all of this. Miho also suspected this was all being orchestrated by another party, not Ayana. 

He did this to get revenge on Ayana's father (?), and used Maki as a pawn, he also liked (? in some sense?) Ayana. He said this about Maki "I thought about using her, because I'm good at dealing with flowers, so I changed my perfectly broken Maki [because of the death of her father] into a revenge devil."

 Ren is unable to combat Yuuya, because Yuuya is evidently the strongest person among them. Ren says "It was really boring, wasn't it? [the revenge circlejerk]" and it ends with this google translation:

[Ren]"Even I can understand. As long as this review leads to a chain, not to stop yet, as long as this world is a boring human world ..." News reported that violent minor incidents can not stop there.

So I guess they refer to the world as boring and Yuuya was just playing with everyone's "you hurt me I hurt you" mentality, while doing the same thing because it's fun?