The Main Characters (Koro-sensei) | Kunugigaoka Junior High School: Teachers and Students of Class 3-E | Kunugigaoka Junior High School: Faculty and Students of the Main Building | Assassins and Other Characters
Lovro Brovski (ロヴロ・ブロフスキ Rovuro Burofusuki)
Voiced by: Takashi Matsuyama (Japanese, TV anime), Kent Williams (English), Víctor Covarrubias (Latin American Spanish)
Irina's Russian mentor in the ways of the assassin and a handler of contracts for assassins around the world, as well as using his wealth of knowledge and experience to train the next generation of professional killers.
- Badass Teacher: He taught Irina many of the things she knows about assassinations, and briefly even took Nagisa under his wing.
- Chekhov's Gun: The "shock clap" technique he taught Nagisa saw little important use until his rematch with Takaoka.
- Drill Sergeant Nasty: His introduction has him hanging Irina from the ceiling with a rope because he thinks she's gotten too lax. But with the students, his methods are much more moderated, though still no less intimidating to Irina, after he caught her slacking off again while the students are training for their summer assassination.Sugaya: Whaddya know. Someone even Bitch-sensei doesn't dare mouth off to.
Maehara: Can't say 'I blame her', man. He's as scary as they come.
- Everyone Has Standards: Played for Laughs. When the kids reveal their intention to use Koro-sensei's perversions to throw him off his guard, Brofski comments that they are brutal.
- Feeling Their Age: During the mock assassination on Karasuma, his first attempt not only fails immediately but he is so injuried in the attempt that he can't try again. These days, he is much better at passing his techniques onto younger assassins, like Nagisa.
- Hitman with a Heart: He seems to care for the assassins he has trained and them to him as well. After he was shown to be alive after apparently being killed by the Reaper, Karasuma asked him to see Irina, who has been worried about him.
- Husky Russkie: Lovro is Russian, and he's one of the most seriously tough characters in the series. For the English dub, Kent Williams even gives him a thick accent.
- Not Quite Dead: In Chapter 76, he was seemingly killed by the God of Death. He was just sent in a coma and has recovered.
- Red Baron: The "Hitman Dealer".
- Retired Badass: He used to be a skilled assassin, but age has taken its toll. He still manages to survive an attack by the Reaper, though, though so he's still pretty tough.
"Red Eye" (レッドアイ Reddo Ai)
Voiced by: Shin-ichiro Miki (Japanese, event anime), Taiten Kusunoki (Japanese, TV anime), Robert McCollum (English), Arturo Sian Vidal (Latin American Spanish)
Portrayed by: Tsuyoshi Abe (live-action)
A sniper obsessed with the color red. He was one of the hitmen hired by the government to assassinate Koro-sensei in Kyoto. After he failed, Koro-sensei, who already noticed, thanked to him for his several attempts, because Class 3-E could learn from it, and Red Eye finally gave up.
- Adaptational Late Appearance: He helps out the class during the Kyoto field trip, which happens quite early on in the manga and anime. However, in the live action movie duology, he doesn't appear until the second movie, since elements of the Kyoto trip were retooled and combined with the school festival arc.
- Back for the Dead: He reappears for a long time in Chapter 98, only to be killed by the Reaper. But it turns out he's alive in Chapter 117.
- Butt-Monkey: All of his attempts failed in hilarious ways.
- Code Name: "Red Eye". His real name is unknown.
- Cool Shades: And it's red-tinted, too.
- Face Death with Dignity: When Koro-sensei comes to him, he says that he's ready to accept his death. Subverted when it turns out Koro-sensei just wants to chat.
- Friendly Sniper: Despite his profession, Red Eye is friendly and amicable.
- Improbable Aiming Skills: He claims to have killed a target in a sandstorm. Both of his two shots towards Koro-sensei were accurate, it's just Koro-sensei is not a normal human being.
- Meaningful Name: He's called Red Eye because he never missed a shot, and so never missed seeing his victim's blood from his scope.
- Punch-Clock Villain: He's only in it because Karasuma contacted him. That said, he's actually a pretty friendly guy.
"Smog" (スモッグ Sumoggu)
Voiced by: Atsushi Imaruoka (Japanese, TV anime), Ben Phillips (English)
An assassin with an obsession for self-made poison who is hired by the Big Bad in the Assassination Island arc.
- Chekhov's Gunman: He first appears as a waiter in Chapter 58. Fuwa immediately recognizes him in Chapter 63 as the man who poisoned the eleven classmates.
- Code Name: "Smog". His real name is unknown.
- Even Evil Has Standards: Before giving the poison to Takaoka, he, Gastro and Grip had some discussion regarding the situation and decide that killing a whole class of innocent teenagers, as Takaoka revealed he had no intentions of actually handing over the antidote, doesn't maintain their reputation. Thus Smog and his associates swapped the poison with a non-lethal food poisoning bug that would eventually wear off, while still giving the victims enough pain to fool Takaoka into thinking that they complied. He even gives the students his own home-made medicine for their sick classmates after the Boss Battle.
- Evil Genius: The guy who relies on poison and is, in fact, the lynchpin of his boss's Evil Plan.
- Fair-Play Villain: Part of why he never used the actual poison in the first place is because Takaoka also had no plans to give them any chance of being cured.
- Fat Bastard: He is an overweight professional poisoner, so he is definiely not the most moral of individuals. However, this trope is eventualy subverted, as even he is not evil enough to kill a bunch of children just to appease a mad man's ego.
- Gonk: His large weight and huge nose are rather unappealing to the eye.
- Master Poisoner: Obsessed with a quality of his poisons, makes all of them himself in his own laboratory and he can tailor their effects for variety of situations, like creating a synthetic virus, that makes the target appear seriously sick, but becomes inactive after a few hours, leaving only minor damage.
- Poisonous Person: He uses poison gas and other poisons. Also, during the School Festival Arc, he mentions that his noodles would be better with some poison, suggesting he eats it too.
- Punch-Clock Villain: He, Gastro and Grip held none of Takaoka's sadism after all. It is just a job, and they do what they are paid to do. They were not paid to kill innocent children, so Smog used a non-lethal poison.
"Grip" (グリップ Gurippu)
Voiced by: Katsuki Murase (Japanese, TV anime), Christopher Sabat (English)
An assassin hired by the main villian in the Assassination Island arc.
- Affectionate Gesture to the Head: At the end of the Assassination Island arc, he pats Karma on the head while telling him that their rematch will be later, when Karma has become infamous enough to merit a bounty, which will definitely happen in his opinion.
- Blood Knight: He wants to test his enormous strength in battles. In the world of assassination, it's almost impossible to have a real battle.
- The Brute: The guy with superhuman strength who guards a hallway, but he's also a Combat Pragmatist.
- Charles Atlas Superpower: His hands can crush skulls and glass walls with ease due to the training he has undergone as a close-range assassin.
- Code Name: "Grip". His real name is unknown.
- Combat Pragmatist: He still uses poison and knives, since he's a professional assassin. He just finds the use of them unfulfilling. Ideally, he would kill his targets with his bare-hands in a straight-forward fight.
- Crossdresser: He likes to accessorize with some makeup and a string of pearls; nobody seems to notice. His true sexuality is unknown.
- Even Evil Has Standards: Like Smog and Gastro, even he had none of Takaoka's sadism and decided that assassinating middle-school kids wasn't worth the bounty for killing Koro-sensei, so he instead opts for direct combat with Karma.
- Fair-Play Villain: It's bad enough he and his partners were hired to attack a bunch of middle-schoolers, but Takaoka attempting to give them all zero chance of survival ends up being a deal breaker.
- Funny Foreigner: His Verbal Tic and the reason for it makes him rather eccentric.
- Good Old Fisticuffs: His forte. He mentions that this skill as an primary assassination weapon gives assassins like him an advantage on missions that require infiltration (As he will never get caught during a body search). This doesn't stop him from using any weapons when time is needed to win.
- Graceful Loser: Took his loss to Karma surprisingly well, since even he admitted that Karma forcefully used horseradish and wasabi sauce into his nose.
- Punch-Clock Villain: He, Gastro and Smog held none of Takaoka's sadism.
- Verbal Tic: He ends most of his sentences with "-nu" to give them a Samurai's tone, because he thinks it would be cool. In the English translation, it's rendered as "is it not?" and similar phrases like "hon" with the anime.
"Gastro" (ガストロ Gasutoro)
Voiced by: Takehito Koyasu (Japanese, TV anime), Mike McFarland (English), Eduardo Garza (Latin American Spanish)
A mercenary from a military who has an obsession of "eating"/licking/tasting guns, who appears in the Assassination Island arc.
- Anime Hair: Black spiky hair definitely stands out among his colleagues.
- Artistic License Gun Safety: This guy has a gun in his mouth for much of his scenes. The gun is even loaded! He claims that he won't shoot himself, though.
- Bunny-Ears Lawyer: Say what you want about the Oral Fixation with his gun; at the end of the day, it took the whole 15 student-team, meticulously coordinated by Koro-sensei, to bring him down. As a matter of fact, he claims that possessing a weird personality quirk is a mark of a veteran assassin, because everyone in that line of work gets weird eventually.
- Code Name: "Gastro". His real name is unknown.
- The Dragon: To Takaoka, as the man's final line of defense and the one talking with him about the Evil Plan, who then relays it to the other two assassins.
- Even Evil Has Standards: As leader of Takaoka's hitmen, he brought Smog and Grip over to discuss their situation and concluded that killing a whole middle-school class would hurt their reputation, a conclusion proven right when Takaoka reveals he has no intention of giving the antidote to students.
- Fish Eyes: His eyes usually face away from each other. They probably enhance his shooting skills.
- Fair-Play Villain: The deciding point for wether or not they should just carry out Takaoka's plan to kill a bunch of kids is when it became clear Takaoka would already completely deny them of the antidote.
- The Gunslinger: He has several guns and is accurte enough to fire at a target peeping out from a small crack.
- Improbable Aiming Skills: Can fire a bullet between the space between the seats of a concert hall with ease. He's also very skilled at making headshots.
- Licking the Blade: Parodied with his gun - he constantly licks it, bites it, and holds it in his mouth, and even uses it as an eating utensil.
- Meaningful Name: "Gastro" is derived from the Ancient Greek word for "stomach", alluding to his Oral Fixation.
- Oral Fixation: With guns! He eats ramen with a loaded gun!
- Punch-Clock Villain: He, Smog and Grip held none of Takaoka's sadism.
- Reckless Gun Usage: He is obsessed with his guns. Where he crosses this line is that he even eats his food using his guns, spooning it using the barrel before putting it into his mouth.
- Super Senses: He has very good ears, as he is able to find out the number of students (+ Karasuma) and how roughly old they are by just hearing their breaths. He is also able to hear out the stolen guns they use, and considering his Improbable Aiming Skills, he must have good eyes, too.
- Willfully Weak: Despite his brutal strength, he refuses to fight Class 3-E at full strength.
- Would Hurt a Child: Aimed for the kill during his battle with Class 3-E. Sugaya's decoy saved Chiba from receiving a bullet between his eyes. However, he admits alongside Smog and Grip that they never actually intended to kill them.
Yuuji Norita (法田 勇治 Norita Yūji)
Voiced by: Ayumu Murase (Japanese), Aaron Dismuke (English)A bored rich kid whom Class 3-E met at the Fukuma Island resort bar.
- Because You Were Nice to Me: Nagisa's kindness and advice towards him prompts him to stop smoking and drinking, and clean up his act.
- Hidden Depths: Initially presented as a mere spoiled rich kid, it is revealed much later that he is also a famous food critic, and his review of Class 3-E's school festival restaurant helps massively boost its popularity.
- Lonely Rich Kid: His parents are often not around, causing him to go out by himself and hang around in bars.
Hiromi Shiota (潮田 広海 Shiota Hiromi)
Voiced by: Kotono Mitsuishi (Japanese), Caitlin Glass (English)
Nagisa's overbearing, controlling mother. She first appears in Chapter 112, where she has been shown to have been trying to completely control Nagisa's life by making every meaningful decision for him and refusing to accept any disagreements on his part.
- Abusive Mom:
- She's very unwell mentally and gives poor Nagisa problems at home. She randomly lashes out at him and projects her unfulfilled dreams and desires into him regardless of what he wants, and is not above being physical in her abuse by repeatedly slamming Nagisa's head when she snaps at him at the dinner table.
- Her own parents were this to her in the Education Mama variety, forcing Hiromi to constantly study academically which leads her to have no time for herself to enjoy certain hobbies like dressing up. If that wasn't enough, all that forced studying didn't help her to get into the college of her choice, which could've resulted in her getting her dream job.
- Can't Take Criticism: An extreme pet peeve of hers. She has a major freak out when Koro-sensei tries to tell her that Nagisa needs to be free to make his own way, not what she wants of him.
- Control Freak: She tries to control and micromanage every aspect of Nagisa's life: his appearance, his school, and his future, and doesn't take it well at all when he opens his mouth to object.
- Disproportionate Retribution: Koro-sensei dares to try to tell her how to raise Nagisa? Well, she'll just burn the Class-E building to the ground!
- Freudian Excuse: She had a miserable childhood and failed to achieve the lofty goals she set for herself in adulthood. This lack of fulfillment caused her to become obsessed with the idea of having a daughter who could live out her dreams for her.
- Hair-Trigger Temper: She's all smiling until Nagisa (or Koro-sensei) try to disagree with her, at which point she devolves into a screaming harpy.
- Heel Realization: It takes some time, but eventually she comes to realize her treatment of Nagisa was wrong and even apologizes to him for it. Adding that she's proud of him for "graduating from her" and finding his own way in life while also promising to be a better parent.
- Jerkass Has a Point: Deconstructed.
- From a cultural standpoint, she's not wrong in calling Korosensei (who's technically a complete stranger) out for criticizing her for how she should be raising Nagisa. However, it falls flat giving her My Beloved Smother tendencies and making clear to Nagisa that she only sees him as a tool to fulfill her ambitions.
- On that note, she's also not wrong about Nagisa technically rebelling against her wishes since she spent all those years raising him, feeding him, and sheltering him. Normally, this would be very reasonable stern telling to unruly, disobedient children in Japanese society, where Honor Thy Parent is very Serious Business. But like the above example, this excludes the fact that not only she could've had another child that would be a girl, views and treats Nagisa as a tool with no consideration for his own wants or needs, get violent and hysterical if he were to disobey in any way, and was willing to commit crimes like drugging and arson to achieve her goals if needed to. For an extra form of irony, Nagisa could've left with his father during their divorce, but he stayed out of a genuine and unconditional concern for his mother's health.
- Motor Mouth: Whenever she enters her angry tirade mood (Nagisa calls it a dark phase), she never gives the other side a chance to reply.Nagisa: I'll go anywhere you tell me for college and work. Just please, let me stay where I am for junior— [thinking] Uh-oh. I defied her during a dark phase. [...]
Hiromi: Watch your mouth! How could I have raised such an ambitionless child? The wounds of failure will torture you your whole life long! I should know, why can't you understand your own mother, who only wants to spare you the same pain? Here I am getting another donation ready for your bad grades! See what your mother does for you? Just who do you think you are?
- Mugging the Monster:
- Hiromi has no idea that Nagisa is being taught how to kill, much less that he developed the ability to camouflage his real intentions as a coping mechanism for dealing with her psychosis. Nagisa could, at any moment, kill her and she'd never see it coming.
- And almost did get into this situation when an assassin confronted both Nagisa and her. Good thing Nagisa's assassination skills prevented this from happening.
- My Beloved Smother: She asserts her control over Nagisa at every opportunity, trying to make every major decision for him in an attempt to guide him through the life path she wanted for herself. She refuses to allow him to have any say and even goes so far as to assert that, as the one who birthed and raised him, she owns him.
- My Greatest Second Chance: In the epilogue, she and her husband meet Nagisa after the graduation ceremony, having reconciled after some counseling from Koro-sensei a month prior, asking their son to give them a second chance to become Good Parents to him. He tearfully accepts.
- New Game Plus: This is the exact metaphor for how Nagisa describes their relationship. Hiromi intends to control Nagisa's decisions so that he can follow the path through life that she had wanted for herself, but was unable to follow through with, without any regard for Nagisa's feelings on the matter, like an NPC in a game. Koro-sensei's advice to Nagisa is to discover his own game route.
- Nightmare Face: She regularly cycles through an entire repository of them.
- Psychopathic Womanchild: Deep down, Hiromi is pretty much an entitled, angsty teen in an adult body whose trying to take back control of her life after so many failures. And unfortunately, has plenty of things wrong in her head.
- Shadow Archetype: She's a very good representation of what Nagisa could end up as had he not any sort of positive adult guidance or friendships. Worst of all, Nagisa would've been way, way worse when taking account of his own "unique" mindset and his talent for assassination.
- Troubled Abuser: She had her own set of problems and failures as a result of her strict upbringing, leading to her own abuse of Nagisa.
- Vicariously Ambitious: Because her life was a series of failures and disappointments, Hiromi views Nagisa as her "do-over" who can do all the thing's she failed at - go to the college she was rejected from, work at the dream job she couldn't get, etc. She even goes so far as to force her son to grow his hair out like a girl, give him a traditionally feminine name, and force him to wear girls clothes, all so she can pretend he's the daughter she wanted, and thus closer to her fantasy.
- Wanted a Son Instead: Hiromi wanted a daughter, but Nagisa is a boy. She copes by forbidding him to cut his hair and forcing him to dress up like a girl whenever he's home.
- You Are What You Hate: In her own mind, she's giving Nagisa personal freedom compared to her own strict, controlling parents. But unfortunately for her, she's really repeating the abuse she suffered on Nagisa in a different way.
Aguri Yukimura (雪村 あぐり Yukimura Aguri)
Voiced by: Ayako Kawasumi (Japanese, TV anime), Whitney Rodgers (English), Azucena Martínez (Latin American Spanish)
Portrayed by: Mirei Kiritani
Class 3-E's former homeroom teacher.
- Alliterative Family: Aguri Yukimura and her younger sister, Akari.
- Arranged Marriage: She was engaged to Yanagisawa as part of an agreement between their parents.
- Beast and Beauty: She was the Beauty to Koro-sensei's Beast. Even before his transformation into a bizarre tentacle monster, he was a ruthless killer lacking a moral compass. She was a beautiful and gentlehearted teacher, and her kindness towards him and Heroic Sacrifice prompted his HeelFace Turn.
- Birds of a Feather: She became friends with Koro-sensei because of their shared experiences as troubled young adults living in abusive conditions.
- Buxom Beauty Standard: During the flashback segment, she is revealed to have fairly large breasts, which is strongly implied to be the source of Koro-sensei's fetish. This is played up again during the Valentine's chapter, where Kayano gives Koro-sensei a chocolate with a picture of Aguri in a bikini to distract him while she tries to confess to Nagisa.
- Cooldown Hug: She rushed towards Koro-sensei as he was going on a rampage after finding out he'll die in a year due to the antimatter experiments conducted on him and managed to calm him down. However, one of the tentacle guns fired toward him fatally wounded her. At this point Koro-sensei realizes that if she hadn't calmed him, he most certainly would've deliberately destroyed the world in his berserker state.
- Died in Your Arms Tonight: In Koro-sensei's arms.
- Dying Declaration of Love: In her final moments, she told Koro-sensei she was happy to die for him because she loved him that much.
- Everyone Can See It: Her students and her sister could easily realize she had fallen in love with a man after seeing her in such a good mood thanks to the original Reaper, now Koro-sensei.
- The Faceless: Her face is never clearly shown in the flashbacks until Chapter 134.
- Forgotten Fallen Friend: The students of Class 3-E largely forgot about her through the course of the series. It was only after Kayano revealed her true motives that the class remembered about their former teacher.
- Fun T-Shirt / Impossibly Tacky Clothes: She wore really weird shirts, which made her students and the human Koro-sensei question her fashion sense. The oni-motif crop top takes the cake, though.
- Go Out with a Smile: She died smiling, happy that she died for the man she loved and knowing he would become a wonderful teacher.
- Last Request: In her final moments, she asked Koro-sensei to teach Class 3-E in her place, so he could learn about looking after others.
- The Lost Lenore: To Koro-sensei. Her death had a huge impact on him and he became Class 3-E's teacher to fulfill a promise he made to her before she died.
- Morality Pet: The first Reaper, later known as Koro-sensei, developed a soft spot for her as she was the first person to be nice to him and look after him.
- Nice Girl: She was kind, considerate, and polite. She was the only person before Koro-sensei to believe in Class 3-E's true potential.
- The Pollyanna: She's remarkably cheerful despite her incredibly tight schedule, her dad's business going bankrupt, and her highly abusive fiancé.
- Posthumous Character: She died before the beginning of the series.
- Sensei-chan: She was young, attractive, nice, and supportive of her students and had a comedic fashion sense for her shirts.
- Single Woman Seeks Good Man: She developed feelings for the original Reaper/Koro-sensei because unlike the manipulative and abusive Yanagisawa, he was genuinely nice to her and supported her in her career as a teacher.
- Star-Crossed Lovers: With the original Reaper, AKA Koro-sensei.
- Sympathetic Adulterer: Justified. By the time she met the original Reaper, and later fell for him, she was currently engaged to Yanagisawa. However, Koro-sensei describes that she couldn't bring herself to love her fiance due to his abusive nature. It also doesn't help that he was a Control Freak, treats her as a tool, and doesn't even bother hiding the fact that he was seeing other women behind her back and does so in front of her, as shown in the manga.
- Together in Death: In the epilogue, Kayano imagines that somewhere she and Koro-sensei are now watching over Class 3-E.
- Too Good for This Sinful Earth: She is one of the few good adults in the series (so good even Asano Sr. had nothing but praise for her and remarks that giving her a few years of experience and she would be an accomplished educator in no time), and she ends up becoming a victim of Yanagisawa's madness.
- Walking Spoiler: Her relationship with the original Reaper, now known as Koro-sensei. How she was primarily responsible for his Character Development and the real reason why he wanted to teach Class 3-E as part of his deal to the world, is one of the overarching mysteries of the series that was only answered in the latter half once the past comes to bite back at Korosensei in the form of Kaede Kayano/Akari Yukimura, Aguri's younger sister, in a form of misguided vendetta.
Sakura Kiyashiki (鬼屋敷 さくら Kiyashiki Sakura)
Voiced by: Hibiku Yamamura (Japanese, TV anime), Jill Harris (English)
A bitter young girl at the Wakaba Park Nursery.
- Character Development: Thanks to Nagisa breaking through her insecurities, she becomes a friendlier girl. In the epilogue, she leads a normal school life and has made friends of her own age.
- Defrosting Ice Queen: Starts off as a very bitter girl belitting Class 3-E, but slowly warms up to them, especially Nagisa.
- Enfant Terrible: Of all the kids at the nursery, she is the least receptive to Class 3-E and even tries to attack Nagisa with a broom. This is because she was left with serious trust issues after being bullied out of Primary School. As Nagisa spends time with her, she becomes nicer.
- Epic Fail: The aforementioned broom attack on Nagisa ends up with her falling through the floorboards and getting stuck.
- NEET: A strangely young example. She's explicitly called "the elite NEET" by a couple of the other nursery kids, and is noted to be too old for the place. Nagisa notes that she's at primary school level, and is "basically just spinning her wheels", but her bad experiences with bullying have made her unwilling to move on. But with Nagisa's tutoring and encouragement, she develops hit and run strategies to outmanoeuvre her bullies and shed this reputation.
- Precocious Crush: Develops one on Nagisa, the only person whom she lets her guard down.
- Small Role, Big Impact: Compared to other characters, she doesn't play as much of a role in the story, being there mostly to hint at Nagisa's teaching ability, and her introduction comes relatively late on. However, she's the one who plants the idea in Nagisa's head to be a teacher when he graduates during a tutoring session.Sakura: Your path seems pretty clear to me. What have we been doing this entire time? You're gonna be a teacher, silly.
- Sour Outside, Sad Inside: Her belligerent personality has been forged from her experience of being bullied in the past.
Voiced by: Kōsei Hirota (Japanese, TV anime), R. Bruce Elliott (English), (Latin American Spanish)
The principal of the Wakaba Park Nursery.
- Cool Old Guy: He's mentioned to specifically take on students who are struggling with the waitlist for primary school and even though this strains their finances, he doesn't seem to mind very much. Once Class E have repaid their debts to him, he even shows up at the school festival with the rest of the kids to help them out.
- Grumpy Old Man: Justified; he doesn't have much reason to be cheerful after getting flattened by Class E's carelessness, since his injury is going to leave him out of action for a long time. He mellows out once he sees how the impact Class E's experience has had on them and his charges, however.
- The Scream: Gets a pretty epic one when Koro-sensei reveals himself to apologize. The latter overdoing it can't have helped.
- Secret-Keeper: He becomes perhaps the only person outside of Class E and the government to know of Koro-sensei's existence after the latter reveals himself to him to apologize.
Rikuto Ikeda (池田 陸 Ikeda Rikuto)
One of Gakuhou Asano's former students, who dreams of being a basketball star.
- A Lesson Learned Too Well: The reason why it led to his suicide. While Ikeda did take his teacher's lessons of being "good" to heart, it has the unintentional side effect of him being an Extreme Doormat whenever he's confronted with a situation involving a bully, who regularly who stole his money. Because Asano didn't teach Ikeda to be "strong" as well as being "good", it likely leaves Ikeda with a self-destructive case of Black-and-White Morality and being unable to differentiate between fighting back or standing up for himself as any other way than "bad".
- Driven to Suicide: The poor guy ended up getting bullied badly enough to resort to suicide. Mr. Asano took it very poorly.
- Irony: Ikeda's personality as a kid regarding academics is practically the opposite of the current educational system that Asano would later implement to atone for his death.
- Morality Chain: Being one of Asano's first students, Ikeda serves as this along with his other two classmates. After he committed suicide, Gakuhou went off the deep end to prevent the same mistake.
- Nice Guy: He was something of a brat when he was younger, but from what little we can tell, Mr. Asano molded him into a friendly, caring student. Too bad he died before we could see any more of this.
- Posthumous Character: Already long dead by the time the series starts, having killed himself thanks to being bullied, which Asano took to be his greatest failure.
- Satellite Character: Only really existed to show why Asano is the way he is.
- Small Role, Big Impact: A character who is only mentioned posthumously; his suicide is pivotal to Gakuhou Asano's sadistic model of education.
Craig Houjou (クレイグ・ホウジョウ Kureigu Houjou)
Leader of "the Wolf Pack", an elite mercenary group hired by the Japanese government to help seal off the mountain and trap Koro-Sensei for his final demise.
- Adapted Out: He does not appear in the anime adaptation, being replaced by a generic soldier. Weirdly enough, this is averted in the live action movie, where he does appear.
- Barbarian Longhair: He has long, unstyled hair.
- Blasphemous Boast: Known as "God's Soldier".
- Curb-Stomp Battle: An interesting two-way variant. On the one hand, he was defeated rather easily by Class 3-E after many chapters of build-up, but this was because they approached him as assassins, deliberately negating every advantage he might gain so as to avoid an actual fight...which would've been in his favor that would've likely seen Class 3-E utterly defeated, as they admit.
- Genius Bruiser: He is a very good fighter, but also a tactician and capable of speaking fluent English.
- The Glasses Come Off: He deliberately conditioned himself to suppress his inner bloodlust while wearing his spectacles, but lets it all out whenever he removes them.
- Graceful Loser: He mentally analyzes the reasons as to why he was defeated, and silently gives Class 3-E his praises while he's tied up.
- Private Military Contractors: He is leader of an elite band of them.
- Shown Their Work: As shown in the image, his glasses do not magnify or reduce the apparent size of his face when looked at closely, revealing that they are plain glass and an affectation.
- Smug Snake: The children finally defeat him with considerable ease, although this was helped by Karasuma lying about how powerful they actually were.
- Worf Had the Flu: As seen above, while he wasn't given an accurate report of Class 3-E's abilities, he was still defeated rather easily since his "trigger" wasn't allowed to go off, which would've put him in a physical/mental state that would've easily enabled him to defeat Class 3-E. The students even comment on this, as giving him even the slightest bit of leeway would've enabled him to defeat them, as despite everything they put him through, he was still conscious afterwards.
Akira Takaoka (鷹岡 明 Takaoka Akira)
Voiced by: Kenta Miyake (Japanese, TV anime), Justin Cook (English)
Portrayed by: Masanobu Takashima
A member of the Japanese Ministry of Defense's Special Services Division, assigned to push the training of Class 3-E and replace Karasuma as their P.E. teacher. He introduces himself as a easygoing father-like figure, but it quickly becomes apparent that he's actually a sadistic drill sergeant who has no problems with subjecting children to violent and unreasonable training regimens for his own benefit.
- Abusive Dad: He acts as an abusive father figure to most of the people he trains. Just imagine how horrific it would be if he had kids of his own...
- All for Nothing: He stole money from the Japanese Department of Defense, hired assassins to try to kill most of Class 3-E, he believed he destroyed the antiode so the poisoned Class 3-E students will die. Wanting to kill Nagisa out of revenge for defeating him. However, Nagisa defeated him again and the assassins that he hired didn't really poisoned Class 3-E students, just only got them sick for a while since they saw Takaoka to be insane. After being defeated the second time, he was exposed and sent to prison and was dishonorbly discharged. He became a disgrace.
- Anything but That!: After losing to Nagisa for the second time, he is reduced into screaming for his life once he realizes that the latter is about to give him the same sweet smile he flashed during their first duel.
- Arch-Enemy: Develops an intense hatred towards Nagisa after he humiliated him in his introduction arc. The feeling becomes mutual when Takaoka destroys the antidote Nagisa needed to save his friends, even though he had already complied to his demands.
- Arc Villain: In his introduction arc and in the Assassination Island arc. Unlike Terasaka, Itona and Kayano, he was not related to Shiro.
- Ax-Crazy: This guy really enjoys beating his disciples into a bloody pulp, regardless of their age. Not to mention poisoning Class 3-E and destroying the antidote.
- Bait the Dog: He is introduced as a fun-loving paternal guy. Is actually a sadist.
- Batman Gambit: To lull Class 3-E into thinking he's a decent guy, he promises to leave if a student can land a single knife-hit on him in a one-on-one match. The catch? He expects none of them to be mentally prepared to use a deadly weapon against an actual human, so he demands that the challenger fight using a sharpened combat knife. The hesitation of using the knife, on top of the fact that no student is even skilled enough to hit him with an anti-sensei knife, will turn the match into a sure-win situation for himself. This is why Takaoka is completely thrown off guard when Nagisa, one of the physically weakest students of the class, decides not to put up a "traditional" fight and instead smiles as he casually walks over to him. Then he aims straight for his neck without any hesitation whatsoever. Takaoka doesn't take it well once the students celebrate Nagisa's win.
- Big Beautiful Man: He's rather cute looking, which serves to make his true colors all the more shocking.
- Big Eater: He claimed that it was the reason he's a bit rounder than others.
- Big Fun: He portrays himself as this with self-depreciating humour, a sunny disposition, a happy smile and a generally avuncular approach to things (with a bag of goodies)... Although, this is what he's hiding as his true self.
- Bitch in Sheep's Clothing: He's so quick to listen to your problems and to sympathise... a little too quick.
- The Bus Came Back: Guess who is the boss that poisoned most of Class 3-E on the island?
- The Coats Are Off: He and Nagisa throw their coats off before their final fight.
- Crippling Overspecialization:
- Of a sort. His short tenure as Class 3-E's PE teacher and the Assassination Island arc subtly display that he is a soldier, not an assassin. He actually has very little knowledge about assassination; otherwise, he would've realized that putting Class 3-E through Training from Hell was pointless, because no amount of training would put them anywhere close to matching Koro-sensei's normal speed and allow them to kill him. That was why Class 3-E was charged with assassinating him, not beating him down and murdering him — normal humans could only hope to catch Koro-sensei off-guard and/or outsmart him, which would mostly require skill and wit, not physical strength and speed.
- It's also why he loses to Nagisa during both duels: he's so used to straight up fights that Nagisa treating it like an assassination completely throws him off his guard.
- It's partly also because of this lack of knowledge that Koro-sensei and Karasuma were able to figure out that he was the mastermind behind the Assassination Island arc. He used the assassins he hired as lookouts and guards, instead of, you know, as assassins.
- Of a sort. His short tenure as Class 3-E's PE teacher and the Assassination Island arc subtly display that he is a soldier, not an assassin. He actually has very little knowledge about assassination; otherwise, he would've realized that putting Class 3-E through Training from Hell was pointless, because no amount of training would put them anywhere close to matching Koro-sensei's normal speed and allow them to kill him. That was why Class 3-E was charged with assassinating him, not beating him down and murdering him — normal humans could only hope to catch Koro-sensei off-guard and/or outsmart him, which would mostly require skill and wit, not physical strength and speed.
- Duel to the Death: He challenges Nagisa to a knife duel in the climax of the Assassination Island arc, right when he blows up the antidote.
- Disproportionate Retribution: Basically tried to kill off every student in Class 3-E with accelerated cancer simply because Nagisa beat him at his own game (even after rigging the match to his advantage), resulting in his co-workers ridiculing him due to his Humiliation Conga.
- Dissonant Serenity: Takaoka's always grinning and sticking out his tongue, whether he's handing out pastries, revealing his ridiculous training schedule, or violently attacking contrary students, until he challenges Class 3-E.
- Drill Sergeant Nasty: Has a "9-sticks-to-one-carrot" philosophy, is more like a dictator than an officer, and "accidentally" leaves a picture of the soldiers he's tortured in front of Karasuma. And he's always smiling.
- Driven by Envy: He's incredibly jealous of Karasuma, who was the most talented member of their unit in the JSDF and quickly rose above him. He hopes that if he turns Class 3-E into the heroes (even if it means killing some students in the process) who will defeat Koro-sensei, then he'll also become a hero and be finally able to order Karasuma around.
- Evil Is Bigger: He's very big and stocky, much more so than his counterpart Karasuma.
- Evil Is Petty: His main reason for taking over Class E's physical instruction and brutalizing them? He's jealous that Karasuma has always been better than him and wants to get promoted over Karasuma. For that reason, he's willing to use any methods to raise the students into elite soldiers... even if it means killing most of them along the way.
- Expository Hair Style Change: After losing to Nagisa and being fired by Asano Sr., he either uses hair gel or his hair is just messy.
- The Faceless: At the time before he was revealed to be the Big Bad of the Assassination Island arc, his face was never shown. Because it would be a spoiler.
- Fat Bastard: He seems nice at first, but he really is violent and sadistic in his "teaching" methods. Somewhat subverted in his second appearance, as he's lost a lot of weight and looks much more trim. Yet, he's a hundred times the bastard he was before, not to mention quite a bit more... unhinged.
- Fate Worse than Death: He is last seen drooling and in a straitjacket, with the implication being that he has gone too insane to even function like a regular person anymore.
- A Father to His Men: He even said that the students would be like his own children, just like his previous trainees. Yeah, as if! He would make your life a living hell if you didn't listen to your "father".
- Faux Affably Evil: He pretends to be a nice "father" to his disciples, only to reveal himself as a crazy, vicious psychopath.
- Final Boss: The final enemy of the Assassination Island arc. He is the one behind the other assassins, the boss holding the prize at the end of the dungeon. One student even refers to him as such.
- Go Mad from the Revelation: Everything about his duel with Nagisa, from the disarming smile, the knife that almost killed him, and the resulting humiliation aftermatch made him vengeful and psychotic. After Nagisa wins their second duel, he shows Takaoka the same smile before zapping him unconscious. It's very likely that this wiped away whatever was left of his sanity.
- Good Scars, Evil Scars: He scratches his skin a lot after losing to Nagisa, after he overheard his colleagues mocking him for his defeat after he returns to HQ.
- Hate Sink: He's a violent, egocentric, child-abusing Sadist Teacher and Sociopathic Soldier who likens himself to A Father to His Men, which coupled with his actions only hammer in how abusive he is, even taking glee in the prospect of killing a bunch of school kids slowly and painfully.
- Hijacked by Ganon: In the Assassination Island arc, he takes advantage of the limited success that 3-E had in assasinating Koro-Sensei to launch his own plot.
- Inelegant Blubbering: In the anime, when Nagisa actually doesn't hesitate from holding a knife and scares him into thinking that he's about to die, his face ends up coated in streams of tears, snot and drool.
- It's All About Me: Who cares if some students die in his training, it's all worth it to save the Earth - for the money and reputation he'd take credit for, and one-upping Karusama.
- Knight of Cerebus: When he shows his true nature, the story shifts from a fun, uplifting comedy into the darker, more serious themes of assassination. This goes double for his involvement during Class 3-E's island vacation.
- Laser-Guided Karma: When he rears his psychotic head, he crosses lines so fast that karmic retribution is waiting right around the corner in the form of Nagisa. This is especially true the second time, as once he destroyed the antidote he effectively signed off his life to Nagisa's No-Holds-Barred Beatdown and undid all of his success up to that point by truly, genuinely pissing the boy off.
- Laughing Mad: He breaks into a fit of hysterical laughter when he blows up the antidote to cure the students, further pissing off Nagisa.
- Mad Bomber: Most notably during the Assassination Island arc, when he blows up a flight of stairs to isolate Nagisa and then explodes the suitcase holding the antidote needed to cure the students while laughing like a lunatic.
- No-Holds-Barred Beatdown: He gives Nagisa a brief but brutal one during their final fight. It doesn't put Nagisa down, however, and he ends up on the receiving end of a swift near-kill.
- Not So Stoic: Takaoka's Dissonant Serenity is shattered in Chapter 41 courtesy of Nagisa. His grinning gives way to shock, then mind-numbing fear, and finally frothing rage.
- Not-So-Well-Intentioned Extremist: According to him, Takaoka's extremely harsh (if not downright impossible) training schedule will be worth it if just one student survives (though he couldn't care less about his students' lives, even going as far as sacrificing one to make the rest follow his orders) and succeeds in killing Koro-sensei, thus saving the Earth from eventually being destroyed...because then Takaoka will become famous for training that assassin and Karasuma will be forced to acknowledge his superiority!
- Obviously Evil: When he's introduced, there are some hints that he's not as nice as he appears. Then it becomes truly obvious: The too-wided eyes, that sadistic smile, and in his second appearance, the self-inflicted scars on his face.
- Oh, Crap!: During his second defeat when he realizes that Nagisa is going to smile at him.
- One-Steve Limit: With Kataoka.
- Outside-Context Problem: He's an ex-soldier entering the realm of assassination, and entirely ignores the actual school part unlike 3-E's other teachers. As such, he enters with physical force in mind which, while useful for an assassin, takes a backseat to things such as agility, accuracy and stealth, and turns all of 3-E's timetable into nonstop Phys Ed, or in other words training. This ends up turned against him, as he in turn has no idea how assassins do things, expecting Nagisa to suffer a Heroic BSoD instead of calmly, coldly walking up to him with a smile on his face and a knife in his hand, and later hiring assassins as lookouts and guards during the Assassination Island arc instead of having them be on the offensive.
- Psychopathic Manchild: He throws a big temper tantrum and tried to murder Nagisa because Nagisa beat him in his own game. Getting fired by the principal and telling him his methods was worthless damaged his ego.
- Sadist Teacher: He's more akin to a drill sergeant than a teacher, instituting a ten-period class schedule, most of which consists entirely of training, and isn't above smacking any disagreeable student (girls included) around if they say anything but "yes sir!".
- Sore Loser: He doesn't take his defeat by Nagisa well. He's convinced that Nagisa cheated during their first duel by using an "unskillful, cowardly sneak attack", demands a rematch to kill him and refuses to listen to his refusal and attacks him. Twice. Both attempts fail spectacularly.
- Stepford Smiler: His smile is totaly fake and the dissonant serenity makes it worse. Irina sees through this immediately, noting that his cheerful personality "seems kinda forced."
- Tongue Trauma: Downplayed. His tongue has a few cuts in the Assassination Island arc, probably related to his insanity-induced facial scars.
- Tyrant Takes the Helm: In his introductory arc, where he briefly replaces Karasuma as PE teacher and assassination trainer, and is both harsher and meaner by a wide margin.
- Underestimating Badassery: He makes a massive mistake in thinking that Nagisa was nothing more than a gangly little kid with absolutely nothing on a professional on him, much less having the capability to actually attack him with a real knife. Then again, everyone short of Karasuma and Koro-sensei thought the same. This quickly goes away when a disarming fake smile and a swift attack-and-grapple puts him on the ground and frothing at the mouth in terror.
- Unknown Rival: It seems that Karasuma wasn't even aware that Takaoka was jealous of him and saw him as a rival.
- Vile Villain, Saccharine Show: He is hands down one of the vilest characters to appear in the series. Even Asano Sr. thinks that he is a brute who should not be teaching children. His cruelty and horrific actions make the series lose it's normally whimsical, comedic tone.
- Villainous Breakdown: He suffers a major one when Nagisa defeats him for the first time. In their second and final battle at the end of the Assassination Island arc, he suffers an even bigger one when Nagisa defeats him for good before tasering him unconscious.
- Walking Spoiler: He was first introduced as a Nice Guy, even though it was early implied that he's not as nice as he acts. Also, he returns as the mastermind of the Assassination Island Arc.
- Would Hit a Girl: His violence isn't restricted to the boys. He fiercely slapped Kanzaki when she defied him, almost knocked-out Kurahashi (Karasuma stopped him at the last second), and later wanted to bury Kayano with Koro-sensei in cement and anti-sensei material.
- Would Hurt a Child: He uses violence against his students/disciples to suppress them. He knees Maehara in the stomach when he complains about their new training schedule, pimp-slaps Kanzaki to the ground, tries to slug Kurahashi in the face, and planned to beat the crap out of Nagisa to subdue the students once and for all. After his loss against Nagisa, he returns to poison the students with a deadly virus and destroys the antidote to make sure that they die slowly and painfully, leaving only Nagisa alive to see his friends die even after Nagisa apologizes to him. He also tries to kill Nagisa himself when they finally confront him. Not to mention his plans for using the money he makes for killing Koro-sensei is to buy middle school children and forcibly give them the same virus to watch them die in agony over and over again.
Shiro (シロ Shiro)
Also known as: Kotarou Yanagisawa (柳沢 誇太郎 Yanagisawa Kotarō)
Voiced by: Ryota Takeuchi as Shiro / Mitsuaki Madono as Yanagisawa (Japanese, TV anime), J. Michael Tatum (English), Miguel Ángel Leal (Season 1), Eduardo Martínez (Season 2) (Latin American Spanish)
Portrayed by: Hiroki Narimiya
A mysterious man in a white robe and a hood. He is Itona's guardian, handler, and home tutor while also acting as his father. He knows a lot of Koro-sensei's weaknesses.
- An Arm and a Leg: In the epilogue, it is implied that the damage to Shiro's body when he crashed into the anti-tentacle barrier was so severe he lost all his limbs, which had been pumped full of antimatter cells beforehand.
- Arranged Marriage: His and Aguri's parents arranged a pity-marriage between them.
- Badass Long Robe: His robe is made of anti-sensei materials.
- Batman Gambit: He knows how Koro-sensei would act and he calculates his personality to prepare Itona's battles against him. Most often, his plans involve endangering Koro-sensei's students, and then attacking Koro-sensei while he's distracted trying to protect his students and keeping them out of harm's way.
- Big Bad: Not just of the non-school side, but of the entire series. He is pretty much responsible for the overarching crisis of the story, as his experiments have not only turned Koro-sensei into what he is today, but made the Moon explode into a crescent, as well as killed Aguri while she was trying to stop Koro-sensei's rampage.
- Big "NO!": In the anime, before being killed by Koro-sensei.
- Bitch in Sheep's Clothing: In his first appearance, he introduces himself to the class with some magic tricks, is seen reading a manga at one point, and generally chuckles a lot and speaks very politely to everyone. He quickly drops the act as Koro-sensei and Class 3-E keep finding ways to foil his attempts, although flashbacks show that he used this same charisma to win over Aguri's parents.
- Body Horror: He injects himself with tentacle cells in order to help the Reaper kill Koro-sensei.
- Brains and Brawn: He makes the plan and preparations for Itona's battles. Later, Kayano becomes the brawn, and even later the Reaper.
- Broken Ace: He was a famous biologist, heir to a wealthy family, and the head of the World Research Foundation. He's also a horrible fiancé, utterly manipulative, and incapable of recognizing his own flaws.
- Composite Character: In the live action film series, he is not only the live action incarnation of himself but also the second Reaper being given his "Korosensei II" form
- Control Freak: This guy revels in controlling others, from his fiancee Aguri, to the original Reaper (later Koro-sensei), to Itona in the present, and utterly hates those that don't go along with what he says.
- The Corrupter: He took advantage of Itona's psychological trauma to turn him into his personal Tyke-Bomb in his vendetta against Koro-sensei. He also nearly made Terasaka kill his classmates with a bomb meant for Koro-sensei (which ended up serving as his catalyst for Character Development), and secretly tried to encourage Kayano's misguided vendetta.
- Crazy-Prepared: He knows a lot of Koro-sensei's weaknesses, and he puts a lot of effort and preparation for Itona's battles against him. From the events that happened in Chapter 128, it is possible that Kayano is the "weapon" he prepared, which was foreshadowed in Chapter 88.
- Death by Adaptation: The anime leaves out his epilogue segment showing him paralyzed and disgraced, leaving the impression that he was Killed Off for Real by the anti-tentacle barrier after being blown away by Koro-sensei's Emotion Bomb during the final battle.
- Death Cry Echo: It happens to him in Chapter 174 and it is just so gratifying.
- Disposable Fiancé: To Aguri Yukimura. They were engaged only because of an agreement between their parents and he treated her like a slave. It's no surprise she ended up developing feelings for his human test subject, the original Reaper (later Koro-sensei), who was genuinely kind to her.
- Domestic Abuse: Towards his fiancee Aguri.
- Dying Declaration of Hate: While the Japanese dub of the anime simply has Shiro screaming a Big "NO!" when he gets thrown into an anti-tentacle barrier (which would be fatal for him), in the English dub it is changed to him cursing Koro-sensei for having screwed him over once and for all.
- Electronic Eye: When he removes his mask, we see that one of his eye is replaced with a mechanical one.
- Evil Genius: The reason why Itona's battles against Koro-sensei are so difficult is because of Shiro's calculations.
- Eye Scream: Lost his left eye when trying to stop the then-transforming Koro-sensei from trashing his research facility.
- Fatal Flaw: Two times out of three, his plans directly fail because he forgot to take Class 3-E into account. Of course, they would probably have failed regardless.
- Fate Worse than Death: In the manga epilogue, it is revealed that he somehow survived being blown away into the anti-tentacle barrier, but the damage to his tentacle-empowered body was so severe he was rendered a vegetable. To add insult to injury, not only was he denied the pleasure of offing Koro-sensei (the bittersweet honor went to his students), but the government finally shut down his lifelong work on antimatter, deeming it highly impractical even for military usage, leaving him a husk of himself stuck in a hospital bed that Nagisa can only presume that he reflects on his wrongdoing and hopefully put his genius to better use. If he recovers at all. Worse, being a Control Freak unable to control anything, including his own body, has to really suck. He may want to die now.
- Faux Affably Evil: As his introduction shows Shiro is capable of acting polite and respectful, but it's all an act to hide his true horrible nature.
- Final Boss: Together with the second Reaper, though he is the first to be defeated.
- Fittingly, the episode where he is finally fought in the anime is titled "Final Boss Time".
- The live action incarnation plays it much straight due to being a Composite Character with the second Reaper.
- Glowing Eyes of Doom: His hood blocks the view of his entire face, including his eyes which are reduced to this.
- Hate Sink: Far more than Tanaka and Takada, who were at least comically pathetic in their attempts at bullying, Asano Sr., who was a Tragic Villain who not only used to be a loving teacher before the bullying-related suicide of one of his favorite students drove him mad, but also ultimately found redemption, the Reaper, whose existence was a tragic reminder of Koro-sensei's past failures as a teacher (for which he atoned with Class 3-E), or even Takaoka, himself another nasty piece of work, Shirou is not only worse than all those villains combined, but, as Yanagisawa, responsible for much of the crisis facing the world throughout the series, with his work on antimatter turning the first Reaper, Koro-sensei, into an unwilling time bomb and blowing up 70% of the Moon. Even his focus chapter devotes time to show how he values only himself and his reputation, morals be damned, to the point of shifting blame for the fallout of the Moon's destruction on his staff while covering his tracks.
- Hoist by His Own Petard: He injected himself with tentacle cells to take his revenge on Koro-Sensei. The same cells destroyed most of his body in the end after he gets blown away into an anti-tentacle barrier.
- In the Hood: His face is always hidden under his hood. It isn't until Chapter 133 where his face is seen for the first time.
- Ironic Hell: For a man who reveled in manipulating people, Yanagisawa spends the epilogue with both his body paralyzed and his reputation tarnished beyond repair.
- Irony: as the series Big Bad his defeat comes in a manner worthy of an unlucky extra (he gets blown into his own tentacle barrier during a fight, and is electrocuted because he took tentacles himself). He even lampshades in the manga in his last conscious moments wondering how he could have acquired such a fate.
- It's All About Me: Thinks everything in the world revolves around him, or rightfully should, and gets very, very violent when it doesn't. To the point of Hair-Trigger Temper.
- It's Personal: Chapter 84 reveals that he has a personal hatred for Koro-sensei. He doesn't want just to kill him, he wants to see Koro-sensei suffer as much as possible at the same time. The flashback reveals why as Koro-sensei cost him an eye and his research facility.
- Jerkass: He's arrogant, manipulative and abusive. He also treated his lab assistants and his arranged fiancee like crap.
- Karma Houdini Warranty: Both Koro-sensei and his own laboratory took the blame for destroying the Moon, so Yanagisawa was able to go scot-free and continue his experiments. Ultimately his luck ran out in the finale, after the government canned the project, with him unable to do anything about it now that he's left a vegetable.
- Knight of Cerebus: Much like Gakuhou and Takaoka, Shiro's villainy is played dead seriously. Especially since he's the reason Koro-sensei is what he is, and thus the reason the Earth is at risk of getting destroyed.
- Lackof Empathy: He couldn't care how many people he hurts, or if he could destroy the world, through his actions.
- Laser-Guided Karma:
- In the final arc, he is caught by Koro-sensei's energy attack against the second Reaper - note that everyone else was getting the hell out as fast as possible, but he chose to stay and watch - and as a result he gets blasted into the anti-tentacle field while infused with tentacles and gets paralyzed.
- He judges people based on their utility to his plans, and is particularly cruel to those he deems "useless". Then he becomes "useless" after not only was he left paralyzed, but his experiments have been finally shut down by the government.
- Laughing Mad: In the anime, when the Reaper impales Kayano.
- Light Is Not Good: He is completely clad in white, and technically is trying to save the world by attempting to assassinate Koro-sensei, but he has an antagonistic role and his methods are extreme.
- Mad Scientist: It was his experiments that turned Koro-sensei into what he is now and that he blew up the moon with a lab rat.
- The Man Behind the Man: He is the real entity responsible of much of the bad things that has happened in the story. His antimatter research destroyed the Moon, turned the original Reaper into the monstrous Koro-sensei, got Aguri was killed by an antimatter container, and manipulated Terasaka (temporarily), Itona and even Kayano.
- Manipulative Bastard: He manipulates Terasaka to help him and Itona against Koro-sensei. And he lies to him about the real plan to guarantee that he would help them.
- Meaningful Name: Invoked; he asks everyone to call him Shiro, which means "white" in Japanese, since he wears white robes. His real name is Kotaro Yanagisawa.
- Never My Fault: He honestly believes that Koro-sensei is directly responsible for the destruction of 70% of the moon, the death of Aguri, the destruction of his research facility, and the loss of his left eye, when in reality, each and every one of those things is direct, and completely documented, results of his own actions.
- Not Afraid to Die: He claims this when Kayano calls him out for staying on the sidelines while everyone else gets hurt. He then illustrates his point by injecting his cells with tentacles to join the battle. Ultimately though, he's proven wrong when while hurtling towards the anti-sensei laser barrier, his thoughts turn to how he can try to get out of the situation before entering denial.
- Not So Stoic: He has a few comedic moments and he has a bit of sense of humor.
- Oh, Crap!: When he realizes that he's about to go flying into the anti-tentacle barrier, his composure disappears altogether and he starts screaming in terror.
- One-Steve Limit: Averted. His first name is very similar to Class 3-E student Koutarou Takebayashi.
- Parental Abandonment: Shiro abandons Itona at the end of Chapter 84 after the latter failed to kill Koro-sensei for the third time.
- Parental Substitute: He is Itona's guardian and acts as a sort of father figure for him until he abandons him.
- Precision F-Strike: The English dub of the anime gives him one when he realizes he's about to get launched into the anti-tentacle barrier."Shit!! No! NO! THE BARRIER LIQUEFIES TENTACLES!!"
- Revenge Before Reason: Is fixated on killing and brutalizing Koro-sensei for "stealing everything in his life." He's willing to risk his own life and the life of others and the world itself to achieve this.
- The Sociopath: Shiro only cares about himself, doing research for recognition, and puts zero value on anyone who might be harmed by his experiments. He recklessly plays with anti-matter cells which results in the destruction of the moon, as well as turning Koro-sensei into a time bomb that will take the world out with him. After realizing the impact of what he's done, he shows no remorse and is only irritated by the impact it has on him. He also treats his fiancee like shit and doesn't even bat an eye when she's killed. He even tells her that if not for her father funding his research, he would happily have used her as his test subject instead of the Reaper.
- Too Dumb to Live: Gives powers to completely destroy the world to not one but two assassins that are referred to as the Reaper, although it's strongly implied the United Nations ordered him to do it for the second.
- Villains Want Mercy: Was screaming and begging to be rescued at the end of Chapter 174.
- Villain with Good Publicity: One of the reasons he was able to go unpunished for so long until the epilogue was because his intelligence was highly sought on how to deal with Korosensei (after all, he created him). He has been manipulating the government into letting him advise them on how to take out Koro-sensei.
- Would Hurt a Child: To test Koro-sensei's abilities in their final battle, he targets Class 3-E and attempts to blow them up in the hopes the latter will protect them, then bosts to a weakened Koro-sensei about how he'll slaughter them once he kills him. He later impales Kayano with a tentacle during their fight.
"The Reaper" (死神 Shinigami)
Also known as: God of Death, Reaper 2.0
Voiced by: Nobunaga Shimazaki (Japanese, TV anime), Ian Sinclair (English), Manuel Campuzano (Latin American Spanish)
Said to be the best assassin in the world. Enigmatic to the point where even other assassins know little about him. He remains a mythic figure for much of the manga, but eventually starts targeting other hitmen with the intention of working his way up to Class 3-E and Koro-sensei.
- The Ace: He's the undisputed master of every possible skill relating to assassination, including several that most assassins don't even consider.
- Adapted Out: He was left out of the live action movie. Instead, Shiro takes the role of Koro-sensei 2.0.
- Alas, Poor Villain: After defeating him for the last time, Koro-sensei apologizes to him for not raising him properly, which ultimately led to his betrayal, and comforts him in his final moments by promising to him that, should they meet again in another life, he would Raise Him Right This Time.
- Arc Villain: From Chapter 98-110, he is Class 3-E's enemy.
- Badass Longcoat: Fitting for someone whose Japanese name "Shinigami" means "God of Death", since he doesn't wear a robe.
- Bastard Understudy: He learned everything he knows about assassination arts from his predecessor, then betrayed him to the authorities to claim the title for himself.
- Bishōnen: When he was working as a flower salesman, he was this. Even keeps this face as the God of Death. When it gets removed however...
- Blood Knight: He's overjoyed that the students managed to oppose him.
- Charles Atlas Superpower: The best hitman in the world for sure, but this guy's abilities definitely push the limit of what is humanly possible. At one point he gives Okajima an uppercut that bounces the poor guy off the ceiling and rebounding him back down to the floor... hard. Later, he's able to shoot Koro-sensei's tentacles with pinpoint accuracy and Guns Akimbo by reasoning that Koro-sensei can't reach his full Mach-20 speed right off the bat. However, Koro-sensei's starting speed is still somewhere around 600 kph. At one point, he even scored a headshot on a guy riding on a Shinkansen train... while he was on another train heading the opposite direction.
- Code Name: "Reaper". His real name is unknown.
- Curb-Stomp Battle: Justified. He's the world best assassin. Assassins do not fight. They kill their targets very quickly.
- Deceptive Disciple: Chapter 134 shows he took his title from his teacher. And it's from the man who would become Koro-sensei.
- Dissonant Serenity: In the same vein as Nagisa, but to an even higher degree. Even while he's threatening to kill the class and Irina, the class can't help but to feel perfectly at ease.
- Disproportionate Retribution: His statement before (apparently) killing Lovro seems to indicate that he did it merely because the latter talked about him as someone to be feared."From the moment you are born I am by your side, always. Do not put fear in the name, the 'Reaper'."
- Don't Fear The Reaper: Invoked; as part of his Reaper persona, he likes to use "Do not fear [...]" as his Catchphrase.
- The Dragon:
- A disciple version to Koro-sensei, back when Koro-sensei was the first Reaper.
- A more literal monstrous version to Shiro in the final arc by becoming a second full-tentacle creature.
- Dragon Their Feet: After Shiro is defeated, he continues to fight with Koro-sensei until he too is forced into the anti-sensei barrier.
- Establishing Character Moment: Fitting to his title, he suddenly appears out of nowhere and (apparently) kills Lovro.
- Evil Counterpart: He has many of the same abilities that Nagisa does. He can hide his killing intent and appear completely harmless, and even uses the same Stunner Clap technique when they encounter each other. Theres also the fact that they were trained by Koro-sensei.
- Also, this blog post (Warning: spoilers) nicely explains how Nagisa's development mirrors the Shinigami's motivations.
- Evil Is Petty: He betrayed his master to the authorities out of spite for not getting enough attention.
- Possibly of the Rurouni Kenshin character Hannya, given how the Reaper uses the same trick of cutting off and deforming his own face in order to be more effective at disguise.
- The way the Reaper cuts off his own face and is revealed to be a skull is very similar to the Captain America villain Red Skull.
- Face Death with Dignity: Dies smiling after finally receiving acknowledgement from Koro-sensei, his former mentor. This is in sharp contrast to Yanagisawa, who screamed and flailed helplessly as he got blown away into an anti-tentacle barrier.
- Facial Horror: Whenever his killing intent leaks through, his face is depicted as either a skull or something horribly mutated. It's later revealed he cut off his own face.
- Faux Affably Evil: He acts nice, but his intentions are anything than that.
- Finger Firearms: He's got a really small gun in his pointer finger. While normally such low caliber ammo has low lethality, his Improbable Aiming Skills more than makes up for it by aiming for a particular area of the heart.
- Finger Gun: Does this when he (apparently) kills Lovro.
- Freudian Excuse: Double-subverted. He claimed to share a similar tragic backstory with Irina to manipulate her into betraying Class 3-E, but later admits that he grew up in a rich family without any wants. He's an assassin because he wants to be. Then played straight with his real backstory, where he never felt like anything but a tool to his master, now Koro-sensei, which led him to betray him.
- Whose backstory was his fake tragic backstory based on? His mentor and the original Reaper, who would eventually be known as Koro-sensei.
- The Grim Reaper: Usually possesses this symbolism, given the english translation of his title, especially in Chapter 98.
- Groin Attack: Karasuma finds an opening for a second and punches his groin. Then he finishes him off.
- Hero Killer: Since his second appearance, he has (apparently) killed secondary characters. Then, in the finale, he mortally impales Kayano, forcing Koro-sensei to tap into his ultimate form.
- Humanoid Abomination: After his defeat, Shiro infuses him with antimatter cells and subjects him to the same experiments he did to Koro-sensei, turning him from a man into a gigantic tentacle monster.
- I Just Want to Be You: He begged the original Reaper to take him on as an apprentice so he could become more like him. Then, after too much neglect and too long without acknowledgement, he betrayed his master so he could inherit his master's title. Finally, he volunteered for Shiro's upgrade experiment so he could become a tentacle monster like his much admired master.Reaper: The tentacles asked me what I wanted. It was to be acknowledged by you; to be more like you; to be you!
- Instant Soprano: In the anime, after Karasuma kicks him in the nuts.
- Karmic Death: He meets his end at the hands of Koro-sensei, the predecessor he betrayed, who stabs him in the heart with an anti-tentacle knife, then, after apologizing to him for being a poor teacher, forces him into an anti-tentacle barrier.
- Knight of Cerebus: By the time he appears, the series takes a far darker turn, evidenced by him apparently killing Lovro and Red Eye, as well as the revelation of his true connection to Koro-sensei.
- Legacy Character: Chapters 133-134 reveal he is the second person to hold the name "Reaper." The original was the man who would become Koro-Sensei, who he betrayed.
- Living Shadow: His stealth technique is such that he appears to a shadow even when in melee combat.
- Master of Disguise: His actual appearance is very plain. Coupled with his enigmatic reputation and talent at hiding his true nature, he's able to effortlessly infiltrate just about anywhere. Except that his actual appearance is a disguise as well. The reason he is this trope is because he ripped of his own skin from his face.
- More than Mind Control: He subverted Irina's loyalty so that she turned against Koro-sensei, Class 3-E and Karasuma.
- Names to Run Away from Really Fast: Yep, his name is Reaper, alright. There's also "God of Death."
- Near-Villain Victory: He nearly succeeds in killing all of Class 3-E and their three teachers, had both Koro-sensei and Karasuma not been so inhuman and unpredictable. He tries again in the final arc, and Shiro's ego-tripping is the only reason he failed.
- Nightmare Face: His real face is close enough to a Skull for a Head.
- Nightmare Fetishist: The entire reason he's a hitman. When he was a child, he saw his abusive father killed by a hitman (the original Reaper, now known as Koro-sensei). The movements of the hitman were so beautiful that he decided then and there to become one too.
- One-Winged Angel: He undergoes the same transformation as Koro-Sensei did, transforming into a monstrous tentacle creature.
- Oral Fixation: With a chocolate bar.
- Power at a Price: Shiro upgrades him into a being that's twice as fast and strong as Koro-sensei, but shortened his remaining life span to just three months.
- A Pupil of Mine Until He Turned to Evil: It has been revealed that he was an apprentice to Koro-sensei, the original God Of Death. After so much neglect from the teacher he admired so much, he betrayed Koro-sensei by abandoning him at the lab they were infiltrating to be experimented on. No coming back from that.
- Revenge Before Reason: He wants to get back at Koro-sensei and Class 3-E because they wouldn't let him kill them on his previous attempt. He is even willing to undergo a Deadly Upgrade that shortens his remaining life-span to just three months to do so. Then it is revealed that Shiro is the one who wanted revenge. Reaper wanted what he always wanted, Koro-sensei's acknowledgement.
- Serial-Killer Killer: Death doesn't play favorites, but comes to all humans without preference. The first couple times the audience sees him, he goes after other assassins.
- Shrouded in Myth: No one knows who he is, or even what he looks like, and yet he's the undisputed number one in assassination according to Lovro.
- Sinister Scythe: Red Eye describes his weapon as an "invisible scythe". It is a metaphor for a gun hidden in his index finger.
- Slasher Smile: Fitting for someone named "Reaper", he he as smile fit for someone who likes scything.
- Sweet Tooth: He eats a chocolate bar when he apparently observe Class 3-E (or Lovro and later while nearly killing Lovro.
- Unwitting Instigator of Doom: While betraying his master to the government was certainly his intention, this caused pretty much everything that happened in the series: his master's transformation into a world-destroying tentacle monster known as Koro-sensei.
- Trademark Favorite Food: During some of his appearances, he's eating a chocolate bar.
- "Well Done, Son" Guy: He wanted his master to acknowledge him and treat him as a student instead of a tool.
- World's Best Warrior: Well, best assassin. There is a keen difference between warrior and assassin, but he could most likely kill the warriors too.
- Would Hurt a Child: At first, he is only trying to harm Class 3-E a little bit by taking them hostage, but when they excite him too much, it gets worse. He also tries to drown them to kill Koro-sensei in a cage. In the final arc, he attacks Class 3-E to keep Koro-sensei from dodging and then mortally impaling Kayano (though she survives after Koro-sensei's last-minute medical operation).
- Would Hit a Girl: He takes Irina hostage and, later, he breaks some of Kayano's ribs after knocking out Yoshida, Muramatsu and Kimura (the cracking sound is actually just the armor). Later, he tries to kill Irina while she's still on his side, so he can get rid of Karasuma.
- You Cannot Grasp the True Form: He's depicted as this in-panel; his bottomless killing intent combined with his skill at masking it confuses and disorients their targets, because it's impossible to see his true nature. As a result, once he reveals his true colors, he's depicted as either a monstrous conglomeration of predatory plants and insects or a Living Shadow. That said, a combatant of equal skill could see his true form. Until the final arc, where he can go from zero to Mach 40 in an instant, so it's hard to actually see his true form.