1-nen A-gumi no Monster

A private girls' school is supposed to be a special, elite educational institution that forms teenage girls, especially those from rich and privileged families, to become mature ladies able to behave gracefully in society...

Except that Class 1-A from the exclusive Suezono High School, the second most elite highschool in Japan, is full of girls who do NOT fit and don't want to either, and is known as "The Class of Monsters". It's completely dominated by a posse formed by a bunch of young girls (Momo Hananaka, Tsubaki Yabu, Nagisa Okuna, Erika Tsusuji and Maki Oda) who enjoy privileged stands in life, and use them to make other's lives HELL. All the teachers who have tried to reign these girls in have ended up resigning, quitting, etc., within a week..

Save for one. A plain-looking man in his early 30's named Tarou Jimi, hired by the school's owner Kanoko Takayama (an old acquintance of his) to deal with them.

Momo Hananaka, a popular teen model and one of the bullies, attempts to get him to quite and even uses a False Rape Accusation... And fails. EPICALLY and HUMILIATINGLY. Despite his unassuming looks and presence Jimi seems to be extremely Genre Savvy, is aware of near all the tricks under the girls' sleeves, and counters every single one of them. Soon it's very clear that Jimi might be THE one able to "tame" or "calm down" the Class of Monsters (or at least the Heel Face Turned Momo), but as it turns out, the bully girls themselves are not just completely monstrous villainesses, and Jimi himself has a very dark past that shaped him into the curt, efficient teacher he is in the present...

And he might be the real "Monster of Class 1-A", in a way.

1-nen A-gumi no Monster ( 1年A組のモンスター, The Monster of 1rst Grade, Class A) is a shonen manga by Hideki, which goes into the Comic Rex magazine by Editorial Ichijinsha. It started in March of 2018 and, as of 2024, is still ongoing.

Tropes used in 1-nen A-gumi no Monster include:

• Abusive Parents: Tsubaki's congressman father Shouzo is obsessed with Tsubaki keeping Erika happy so she won't reveal that Tsubaki killed a boy who harassed her and ruin the family's reputation; as she grows up, he keeps pulling strings to cover up for her misdeeds and even her crimes, while keeping her in the dark regarding how he knows about Erika. When Tsubaki decides that she wants to turn herself in for the shit she's done, he violently beats her up; her mother Masami, who had tried to soothe her before, does nothing to stop it and just tries to smooth things out after Shouzo has hit Tsubaki . Then she realizes that he knows about Erika's shit... and she breaks. And almost breaks her parents with her.
  • Mari's parents are neglectful to pretty much criminal levels.
• Accidental Kiss: Once, Momo tripped on Jimi when she went to his (messy) apartment to check on his well-being, and their lips met...
• Aloof Dark-Haired Girl: Tsubaki, a dark-haired beauty who's also cold and cruel and NOT liable to go the Defrosting Ice Queen. At first, at least. She turns out to be a Broken Bird with serious, SERIOUS guilt issues.
  • Also Nagisa Okuna, in a more tomboyish version. She has her reasons.
• Alpha Bitch: At first, Momo Hananaka seemed to be the ur example in the class. Once she fails to get Jimi expelled and falls out of grace, however, she becomes a sort-of Lovable Alpha Bitch instead, and it's shown that the real Alpha Bitch is Tsubaki Yabu - she's ruthless, very creative and sadistic in her bullying methods, manipulative as FUCK, etc. And then, the REAL AB is revealed - it's Erika, the one who manipulated Tsubaki into being who she is.
  • In the past, there was another... And her name was Yuriko Kurosaki.
• Always Someone Better: The root of Maki's loathing of Momo
• Apathetic Teacher: When Jimi isn't a mix of Badass Teacher and Psychologist Teacher, he's this. Mostly when not at work.
• Attempted Rape: In an attempt to break Jimi, Tsubaki had Momo tied up and set to be gangraped by a bunch of guys she hired - trying to reproduce the incident where Jimi's once-student Yuriko was sexually assaulted by her classmates and then Driven to Suicide, plus force him (and Maki and Mari) to see it through a tablet device. However, Momo went Badass Damsel and managed to literally kick the rapists' asses. And not only that, she attacked Tsubaki herself in retaliation.
• Badass Teacher: Tarou Jimi, in spades. He turns out to have HORRIBLY tragic reasons to be that way, however.
• Bandage Babe: Mari Banri, especially at the beginning. It's because she was so horribly harassed by the posse and especially Momo, she turned to self-harm as "relief".
• Beta Test Baddie: Erika
• Bitch in Sheep's Clothing: The Posse. Holy. Shit. How. Momo, Maki and Tsubaki are especially addicted at playing the role, though Momo tones it down noticeably after her Heel Face Turn and so does Maki, to a degree. But Erika is actually the worst, since she is the one who manipulated the once-kind Tsubaki to become the bitch she is and later was quite passive-aggressive to Nagisa.
• Blackmail: Of sorts. Both Jimi and his once sempai/First Love, Yuriko Kurosaki's older sister Kanoko Takayama (who's now the owner of the Suezono school), have information on each other's parts in the debacle surrounding Yuriko's suicide. Since Jimi is "socially dead" thanks to the incident, he uses his share of the data to blackmail Kanoko into giving him a job under the implicit threat of releasing said data and ruining the school's reputation; from her part, Kanoko uses hers to keep Jimi silent about it all as well.
  • Even more so, Yuriko used some pictures of herself kissing Jimi to blackmail and manipulate him into letting her and her friends physically abuse him, then record it in videos. And thn the boys repented of their actions and tried to blackmail Yuriko back with these videos...
• Book Dumb: Momo. To the point that she almost gets expelled for it at some point.
• Break the Haughty: Momo, holy shit. Her attempt to break Jimi by falsely getting him labeled as a rapist failed spectacularly, she was harassed and bullied to near maddening degrees by her "friends", and that more or less made her a still childish and proud, but much kinder person. (If moody)
• Butt Monkey: Momo.
• Childhood Friends: Tsubaki and Erika are friends from elementary school days, and Nagisa joined in junior high. Erika and Tsubaki's deal turns out to be horribly subverted, though.
• Coming of Age Story: Tenjiku's subplot shows that she's a late bloomer example.
• Compensated Dating: A girl from Tenjiku's class (Hitomi Tsukishita) does this to support herself and her Ill Girl mother, and claims she only dates her sugar daddies but doesn't have sex with them. She gets caught by Nagisa, and first tries to bribe her, then to ropes her into coming to one of her dates with a very rich man... Nagisa gets so creeped out that she beats up the guy, so both girls are arrested and both Jimi and Tenjiku have to bail the two out. Later, however, she goes after the guy again and he leads her to a Love Hotel, then forces her to strip nude and verbally humiliates her. Fortunately Nagisa and the teachers show up to save her, and despite his Apathetic Teacher apporoach to the girls from other classrooms, Jimi goes through quite the lengths to get info on the guy. (He says it's because Nagisa is involved, though). At the end, Momo uses her connections to get Hitomi some gigs that can count as a part-time job.
• Cool Teacher: Jimi's sort-of Only Friend among the teachers, Aoi Tenjiku, is a very idealistic young lady who badly wants to be this.
• Dead Little Sister: Yuriko, for Kanoko.
• Does Not Like Men: Nagisa really, REALLY hates guys. Especially adult men. Much later, she tells Tenjiku-sensei that sdhe may have been taking her anger out on them due to her terrible relationship with her dad.
• Enfant Terrible: Tsubaki once killed a boy by pushing him on the path of a train when both she and the victim were in elementary school. It turns out to be subverted, though: the boy was bullying Erika, Tsubaki initially was trying to push him away from her, and she was horrified by the results until Erika herself got to her head.
• Everyone Has Standards: Nagisa may be a member of the Posse who terrorizes Class 1-A, but she's among the few who stand up to Tsubaki's bullshit and does worry for her as a person. She also seems to genuinely hate when adult men take advantage of young girls because of her parents' divorce when she was in junior high, caused by her finding out about her father's "liking" for teenage girls.
• Every Scar Has a Story: Mari has scars on her arms from her attempts at self-harm
  • Jimi turns out to have burn scars on his legs from his former students burning him with cigarettes at Yuriko's behest, and scars on his wrists from suicide attempts.
• False Rape Accusation: As said above, the action is kicked off when Momo tries this on Jimi and completely fails.
• Five-Bad Band:
  • Big Bad and Evil Genius: Tsubaki
  • The Dragon: Erika. Actually, The Girl Behind the Other Girl
  • The Brute: Nagisa
  • Dark Chick: Maki, and Momo until her Heel Face Turn.
• Gone Swimming, Clothes Stolen: Given a spin later in the series. As Nagisa is having a Shower of Angst in the School Festival arc, Maki calls her out on how her aloof attitude is NOT helping the class with their project to have a Meido café. Then she goes away, Nagisa storms out of her stall... and finds out Maki has stolen her school uniform and switched it with a Meido outfit. Naturally, Nagisa is NOT amused, even when Maki later returns the clothes.
• Heel Face Turn: Momo has hers pretty early. Maki follows some time later, and then Nagisa may have her own...
• Important Haircut: Nagisa gave herself one when her parents got divorced due to her father being outed as an Ephebophile.
• Look Both Ways: Nobuko Kase, a girl who witnessed Tsubaki's attempted murder of Mari during a class trip and was terrified of being framed as the culprit, tries to go to Tsubaki's house but panics and runs away - and this happens to her. She barely survives, but is severely wounded and traumatised.
• Misplaced Kindergarten Teacher: Aoi Tenjiku gives vibes of being one of these.
• Not So Different: Tsubaki becomes firmly convinced that she and Jimi are this.
• Paparazzi: One of the, Yasuaki Horibata, zooms into Suezono High and Jimi because he covered the incident of six years ago that ended up with Yuriko dead and Jimi completely shattered.
• Passionate Sports Girl: Nagisa Okuna, the Tomboy of the group. In fact, she's a Scholarship Student who got into Suezono because of her volleyball skills.
• Peer Pressure Makes You Evil: Some of the girls in Suezono High's 1-A Girl Posse are gigantic, enormously cruel bullies, but it's clear that at least some of them do it for pull and to stay in their social group. When Momo fails to harass Jimi into leaving, she's expulsed from the posse and heavily harassed by her once-"friends" who consider her inferior for failing them, but more or less has a Heel Face Turn; later, another girl (Maki) has her status within jeopardized after it leaks that she leaked details of the incident with Momo and, as a way to stay in, the Alpha Bitch and leaderess (Tsubaki) tells her to actually harm Momo with acid... which turns out to be near harmless one. And later it's revealed that Tsubaki herself was subjected to this, thanks to her False Friend Erika's mix of emotional abuse and blackmail, and Nagisa let her pull all kind of shit in a misguided attempt to watch over her and Erika. Momo even mentions the trope when Maki confronts her:

Maki: "I'm not doing this because I want to! It's just that... if you only disappeared from my life, I could continue hanging out with Tsubaki and the others...!" Momo: "Is staying in the group really THAT important to you? (...) Maki, aren't you your own person?!"

• Pervert Dad: NOT Played for Laughs. Nagisa used to be a very cute and girly Daddy's Girl... until she took a peek in his laptop and found his Porn Stash, which included MANY pictures of teenage girls in different states of undress, plus (thankfully clothed) pictures of Erika. The nail on the coffin was her overhearing a fight between her parents about it - and about how he got Erika's cellphone number and directly contacted her, with his wife accusing him of wanting to har mer. The Okunas got divorced, Nagisa stayed with her mother and, with Tsubaki's family's help, broke all bonds with her dad.
• Psychologist Teacher: Taro Jimi is maybe one of the most straight examples in recent school manga, plus a weird mix of this and Apathetic Teacher. The reasons come from his Dark and Troubled Past, however.
• Sailor Fuku: Suezono's uniform mixes elements of both fukus and Western blazers. Jimi's old school played this straight.
  • The flashbacks to Nagisa's past show her in a fuku and with longer hair in her junior high years, alongside Erika and Tsubaki.
• Save Our Students: Subverted: Jimi dedicates himself to help his students, but is much more cynical and distant than the average. He turns out to have an horrifying Dark and Troubled Past where he TRIED to be this, but utterly failed because the local Alpha Bitch Yuriko used that to have some of her classmates violently attack him.
• Scholarship Student: Nagisa.
• Sempai-Kohai: Taro Jimi was the kohai to Kanoko Takayama's sempai. He still refers to her as such and even says she was his First Love even when now they're mortal enemies after Yuriko's fall and death.
• Shower of Angst: Nagisa has one during her A Day in the Limelight chapters.
• Stock Shoujo Bullying Tactics: W. O. W, this manga is chock-full of it. From Momo bullying Mari to the point she started self-harming, from Momo being bullied by her "friends" after he fall of grace, to Maki specifically harassing Momo out of envy and under Tsubaki's manipulations, to Tsubaki almost killing Mari by pushing her off a cliff...
  • The dark incident involving Jimi's past has to do with this too. Six years ago his student Yuriko Kurosaki was harassed by her classmates, then was all but shouted to gangraped by some of them and she hung herself, and Jimi was accused of freezing up in fear when he walked into the rape scene and not doing anything to help her. But later, it turns out things were FAR more complicated: Yuriko was actually the ringleader of a group of students who savagely harassed the young Jimi, under threat of revealing a picture where Yuriko kissed him and accuse him of harassing her.
• Strong Family Resemblance: Kanoko Takayama had a younger sister who died as a teenager, and the flashbacks show that they looked alike a lot. Said sister was Yuriko.
• Teacher-Student Romance: Logically, the trope's alluded to in the story. To start, Momo tried to make it look like Jimi assaulted her, but he sees through her and uncovers her BS. She becomes very, VERY tsundere for him later.
  • Mari falls in love with Jimi after he and Momo stop her from committing suicide. Jimi, logically, wants NOTHING with it. It's strongly implied that his and Yuriko Kurosaki's VERY complicated past was to blame: she had a photo of her kissing him and used it to Blackmail the guy and tormenting him.
  • As of chapter 50, it looks like Momo is developing feelings for Jimi, as she kinda fantasizes about her Accidental Kiss with him while in the bath. It's fully confirmed in chapter 66, when she first gets very shocked when she sees him smiling for the first time - to the point of spilling hot water on her maid uniform... and then she goes to the infirmary to talk to Mari and openly tells her "I thinkl I'm falling for Jimi-sensei!"}
• Tomboyishness Upgrade: Played for Drama. Nagisa Okuna used to be very girlish and cute, until during her junior high years her father (whom she was very close to) was revealed to be an Ephebophile and fixated on her friend Erika Tsutsumi, which triggered her parents' divorce; she reacted to such a cruel reveal by, among other things, cutting her hair and shredding a very girly and expensive dress she had...
• Toxic Friend Influence: Erika played this VERY straight to Tsubaki and, to a degree, Nagisa
• Tsundere: Momo, especially to "the stupid virgin teacher" and to her once victim, now close friend Mari.
• Used to Be a Sweet Kid: Nagisa and Tsubaki
• Vomit Discretion Shot: Played unusually seriously when Jimi vomits twice due to being severely stressed. The first time is triggered by Mari trying to touch him, and the second by Momo tripping on him and then giving him an Accidental Kiss.
• Wrong Genre Savvy: Aoi Tenjiku is a bit of a Wide-Eyed Idealist; she seems to think she's in a bright Save Our Students-like series and that she can become its protagonist. She has her reasons, but still.
• Yandere: Mari has touches of this at first. She's quite more tragic than the average one, as she's been severely damaged by the bullying and a murder attempt she went through and this is why she clings so much to Jimi. But she slowly begins to get better with time.
• Zettai Ryouiki: Momo