Badass Bookworm: Even though the students are in Class E, the school is still established as a very good school in the country and most of the students are pretty good at studying, just not good enough. In the recent Final Exam arc, they managed to beat Class A in number of top spots for individual subjects secured.
Child Soldiers: Partially subverted in two ways. Their teachers are trying to ensure they can have a normal life in addition to their training, and they're training to be assassins rather than traditional soldiers.
Downplayed Trope: Generally speaking, the students of class E tend towards having more subtle characterization, with few traits that stand out strongly. This doesn't mean that their characters are simplistic. Like real people, they merely exhibit various tropes in a way that is weaker than normal in fiction.
Fantastically Indifferent: After you've been drafted to assassinate a mach 20-moving, super-teaching eldritch smiley, your surprise may become somewhat miscalibrated. For example, when seeing someone casually walk straight through a wall, you may think "Use the damn door!" instead of "How did he do that!?"
Named After Somebody Famous/Shout-Out Theme Naming: The names of most of the characters come from the tale of the Forty-seven Ronin, with the students of class 3-E being the ronin themselves. However, many of the characters have altered names, either in how they are read or what kanji are used to write them. This may be a further reference to the oldest fictional versions of the story, which were written in a time when plays depicting current events were censored. To avoid that, the plays based on the story used different names and a different time period.
No Pronunciation Guide: Many characters had the kanji for their names released without the correct reading specified for a long while. As of the fifth volume all readings are confirmed, but some websites still list them by the translator's early guesses.
Took a Level in Badass: As a result of the assassination training they have to undergo, all the students have taken some levels in badass
Class 3-E - Teachers
"Let's have an assassination that will make people smile and puff out their chests with pride. Each and every one of you can do that. You are talented assassins with hidden strength. That is advice from your sensei, as a target."
The homeroom teacher for class 3-E of Kunugigaoka Junior High School, and the main antihero of Assassination Classroom. He is responsible for carving out a large chunk of the moon to make it a permanent crescent moon, and plans to destroy the earth after teaching class 3-E for a year.
Bunny-Ears Lawyer: Moon-killing, manga-drawing, supersonic, perverted, but really good teacher, anybody?
Chivalrous Pervert: He doesn't hide the fact that he loves women with big boobs, but he also defends Irina from a group of perverts who were harassing her and is an all around good person—aside from that destroying the world issue.
Clark Kenting: When he wants to go out in public, he sticks a fake nose on his face and puts on a wig. Amazingly, it works.
Drama-Preserving Handicap: He isn't allowed to injure any of the students or staff, according to the agreement he made to be allowed to teach class 3-E. Never mind the human students, even Itona wouldn't stand a chance against him if he were willing and able to retaliate.
Even Evil Has Standards: Koro-sensei is not pleased when one of his students' collaborative attempt at killing him almost injures one of their own.
Excuse Me While I Multitask: When people try to kill Koro-Sensei he's usually doing other things, such as meticulously trimming his attackers' eyebrows or giving a fighter jet a polish in mid-air
Self-Duplication: He can move so fast he can make selectively tangible afterimages. Chapter 12 shows him making one for every student in the class to personally focus on their weak subjects. He even leaves one outside to rest from all that work.
Explaining Your Powers To The Enemy: Subverted. When he bothers to say anything at all, he only tells the basics, and often leaves out key details, like the fact that his mucus protects him from his weakness to water.
Extreme Omnivore: Aside from his habit of flying around the world to eat any food he wants, he has been seen eating pens, knives, sodium hydroxide, aqua regia...
Flash Step: Koro-Sensei has a top speed of Mach 20. During one assassination attempt, he easily dodged the attacker while meticulously trimming his attacker's eyebrows. When attacked by state of the art fighter jets, he gave them a mid-air waxing. When attacked by knife armed students, he disarmed all of them, then replaced the knives with tulips without their noticing.
A Form You Are Comfortable With: Debatable, but the first chapter makes it clear that his current appearance is not his true form. Surprisingly, sans tentacles, his shadowy true form seems human-like.
Gadgeteer Genius: Has extensive skill and knowledge with machines and electronics. He was able to majorly upgrade Ritsu's capabilities for a relatively cheap sum of money and also built a custom motorcycle with a frame made of wood.
Gone Horribly Wrong: A super-powerful artificial creature, created to be the world's savior, now on course to destroy it in less than a year.
Guile Hero: For all his power, he almost always solves problems with trickery rather than brute force alone, often to the effect of bettering his opponents.
Healing Factor: Koro-Sensei, amongst other abilities, has the power of regeneration. Even if he gets hit with the Applied Phlebotinum weapons, unless his body is almost completely destroyed, he'll recover in seconds.
Helping Would Be Kill Stealing: Though he may guide and coordinate them, he lets his students handle problems on their own whenever they're capable of it, which they usually are.
Informed Attribute: He is an evil monster who intends to destroy the world, and only hasn't done so yet because it would be boring... Or so the narrative tells us. He actually acts in a way that has been compared to Buddha on this site, helping everyone around him improve themselves. The dissonance is so extreme it's hard to imagine that it's not Foreshadowing some kind of reveal.
Kryptonite Factor: A rubbery material that is not described beyond being "special" and able to disrupt his cells on contact. It can be fashioned into knives, BB pellets, or clothes, and is apparently available in abundance.
Major Injury Underreaction: He casually blows or slices off his own tentacles, sometimes several at once. Supposedly this causes emotional disturbance that slows him down for a while afterwards, but that's still way less of a response than such injuries warrant. Of course, he can regrow his tentacles after a few seconds.
Messianic Archetype: For a creature who intends to destroy the world, Koro-sensei is an expert in making people change their ways for the better. Karma, Irina and "Red Eye" are all examples of this charisma and wisdom Koro-sensei possesses, along with his interactions with all of Class-E.
Mundane Utility: He uses his super speed for teaching and for traveling to different countries between his breaks to buy foods.
Nigh-Invulnerability: Is able to withstand fire from multiple high-caliber machine guns at once. Apparently, the only things that can seriously harm him are the special anti-sensei material, and other beings similar to him, like Itona.
Weaksauce Weakness: Weak to water. Specifically, his body is sponge-like. Even a day with high humidity causes him to swell up comically. If he actually found himself immersed in water it would certainly get much worse, and slow him down significantly. The mucus his skin releases can protect him from it, but it can be depleted.
Also, the Anti-Koro Sensei weapons are basically his Kryptonite, which is notable as it's completely harmless to normal humans.
"As part of the same group entrusted with the mission of saving the Earth, I think of you all as fellow professionals. As professionals, I believe the barest minimum you should receive as compensation is the guarantee of a normal middle school life."
An agent sent from Japan's Ministry of Defense to supervise Koro-Sensei. In Kunugigaoka Junior High School, he was admitted as an assistant teacher for Phys. Ed. in class 3-E.
The Ace: He's certainly beyond merely competent in a lot of fields... Not his fault he's against a super-sonic, unkillable octopus.
Bad Ass Normal: He's in an entirely different league from any other human character.
Knife Nut: Although not restricted to knives (or nuttiness), he's good with them and training others to use them. Very good.
Nice Guy: Comes across as this. However sternly and stoically he acts, he does ultimately care a lot for others and will go all out for them... and it's very obvious to all concerned.
Not So Stoic: He tries so hard to maintain a professional demeanor, but considering the insanity of the situation he finds himself in, he can hardly go five minutes without getting visibly angry.
Only Sane Man: In comparison to other teachers or even his own (shady) bosses? Oh, yes.
Papa Wolf: He's very protecting of the Class-E students, and will not stand for anyone physically hurting them.
Stern Teacher: Very much. But, the pupils actually like him for it, even if they acknowledge it at the same time.
An assassin who was sent to class 3-E to kill Koro-Sensei. She teaches English and infiltration assassination.
Action Fashionista: Very fashion-conscious, loves her Sex and the City and teaches English to it, takes every opportunity to dress-up she can... packs weaponry and killer-intent as an assassin. That's most of the boxes ticked, then.
Bunny-Ears Lawyer: Fashion-obsessed apparent airhead. Who can teach multiple languages and interpersonal interaction surprisingly well as a result of her training as an assassin.
Butt Monkey: Part of her comedy value. She's quickly learned there are a select few people her usually reliable skills aren't that useful against. Doesn't stop her trying (and failing), though. Henna tattoos of total embarrassment may be involved on occasion...
Child Soldiers: Made her first kill when she was 12, which is even younger than her current students are.
Cunning Linguist: Speaks ten languages, which she learned by taking lovers in the countries where she carried out her hits.
Dark and Troubled Past: Implied as she told her students that they were lucky to be born in a peaceful country.
The Ditz: If she wasn't an assassin, you'd wonder about her ability to survive.
Hair-Trigger Temper: When she's frustrated, you know: she doesn't exactly hide it (unless from an actual target: then she does bottle it). Added to a set of Berserk Buttons of questioning either her sex-appeal, her competence or her dedication to killing a certain octopus... and stop calling me Bitch-sensei.
Hidden Depths: She’s well aware that a woman’s beauty will not last for long and one should do everything she can to make herself shine as a woman.
Honey Pot: What she did before coming to this school.
"I bet I could kill him. I mean, this teacher doesn't even see me as a hitman."
The most often seen student, and the main perspective character. Fell into class 3-E at the end of the previous year due to poor grades. Timid, cautious and relatively weak, he prefers to observe and collect data on Koro-sensei's weaknesses rather than participate in assassination attempts. Despite that, or perhaps because of it, he is considered to be one of the best assassins-in-training in the class.5th best marksmanship, boys' side. Ranked 6th in the school for English.
The Ace: Even before he trounced Takaoka he was the only normal human to threaten Koro-sensei to the point where he had to use his molting ability. He is also readily acknowledged as being the go-to guy for information and analysis.
Anime Hair: He seems to have odd pigtails in the back of his head, but since we've never seen it down—even when he's swimming—it just may be its natural shape.
Ambiguous Disorder: There is something off about him. He isn't intimidated by having to wield a potentially deadly weapon or having to threaten someone's life, even though it's specifically pointed out that he should be. Yet he isn't generally callous or manipulative in the way a sociopath would be. He just has no compunction against killing for some reason, like you'd expect of a veteran hitman. Except he isn't one, yet.
He is supposed to be intimidated by the thought of using a real knife, but not only does he show no hesitation, he is clear-minded enough to attack using the dull side of the blade.
Animal Motifs: An enormous snake. Symbolizes his viciousness and his ability to hide in plain sight, like a snake in the grass.
Attractive Bent-Gender: He only needs to put on a skirt and some hair decs to pass off as a really convincing girl, and even catches a guy's attention like this.
Audience Surrogate: For younger audiences in Japan, a character who struggles in school and suffers from lack of confidence would be extremely familiar to a lot of people. By this interpretation, that would make his ability to summon up will when needed and his various talents Wish Fulfillment.
Awesomeness by Analysis: Downplayed. His abilities are hardly superhuman, but he still possesses the best sensibility and instinct in the class when it comes to planning an assassination.
Beware the Nice Ones: Sure, he's a nice guy who gets along with everyone in the Ragtag Bunch of Misfits that is class 3-E, and is even a vegetarian to boot. But on the other hand his stealth and sheer blood lust make elite veteran soldiers shit bricks.
You know that propensity to note down people's weaknesses? Well, seems he isn't above using what he learns to character assassinate you for a just cause (or just a distraction), either. Psychological warfare when needed? Check.
Book Dumb: Relatively speaking. He did fall into class E due to poor grades, after all. But when it comes to applying the knowledge he has, he's more like a Teen Genius.
Bread, Eggs, Milk, Squick: The three things he wants most are to get to know everyone in his class, to live without leaving things unfinished, and to kill his teacher.
Dissonant Serenity: Walking up to Koro-sensei with a grenade around his neck and knowing full well he could get seriously injured or even die with nary a change in his usual expression? Check. Taking down an elite veteran soldier by casually walking up to him in a way he himself describes as as if I were walking to school and slashing at his neck? Check.
This is considered to be his greatest talent: the ability to completely hide his (considerable) killing intent, making him the most assassin-like of all the students.
Dude Looks Like a Lady: There are fans convinced he's still a woman posing as a man. Lampshaded in chapter 43, which also definitively confirms his gender—he wears a male swim suit, and several female students note how up until that point it had been hard to tell.
First Person Peripheral Narrator: While Koro-sensei is the central character, Nagisa provides most of the narration, usually in the form of explaining the thoughts of the whole class.
Heroic Self-Deprecation: He's at least competent at everything he does, but you wouldn't think so by how low his opinion of himself is unless his killing intent is switched on.
Odd Friendship: With Karma. Despite being close and long-time friends who are often seen together, they're quite different. Karma is extroverted, aggressive and crass. He takes his time, enjoys taunting his opponents and attacks them recklessly and brutally. Nagisa is calm and polite. As an assassin, he's far more professional than Karma, hiding his intentions and going straight for precision kills before the target even expects anything.
Silk Hiding Steel: Male version. He is certainly not your traditional badass, but he can make himself appear so innocent that a man intent on beating him into submission was stunned into inaction long enough for him to get in position for what could easily have been a killing blow.
Troubling Unchildlike Behavior: It's present for the entire class, but he's a very notable case. He's just too much of a natural at assassinations, which becomes even more troubling when juxtaposed with his usual behavior.
"Well Done, Son!" Guy: It's not brought up often, but his parents don't look him in the eye ever since he landed in class E, and he would very much like to make, if not them, at least someone proud of him. And he's literally willing to kill to reach that goal.
Completely Missing the Point: When the students push to have Irina Sensei kicked out of 3-E, her reason isn't Irina's initially poor teaching and lack of faith in the class, as it was with the other students. It was her boobs.
Foil: To Nagisa of the Childhood Friends version. She'd probably like to be something a littlemore intense, but... until he bothers to notice, she'll settle for being the friend he can bounce ideas off and occasionally make good points of her own. She provides much of the useful excuse for his First Person Peripheral Narrator status.
Keet: He gets really happy whenever he accomplishes something.
Weak, but Skilled: He lacks the strength needed to throw fast balls, but has excellent flexibility and control that allow him to use technical pitches to great effect.
"I think not enjoying yourself in a classroom where it's okay to kill is such a waste."
A student who joined late due to being suspended from school for trashing his teacher's office. He started off holding a major grudge against all teachers, and as such is one of the students most dedicated to the assassination. Koro-sensei helped him get over that particular issue, but he is still a near-sociopath who loves to beat people into unconsciousness.3rd best marksmanship, boys' side.
The Ace: One of the most physically capable students, ranked third in marksmanship, as well as the best in academic performance. He has the second best track record among the normal human students when it comes to threatening Koro-sensei.
Bad Ass: It was always clear, but during the island assassination arc, he takes on an adult pro assassin, and it's obvious the whole time that he's got the guy's number, both in hand-to-hand and in guile.
Biting the Handkerchief: He isn't crying, and it isn't played for laughs, but biting his test papers is a clear sign of how upset he is by failing to beat Gakushuu in the math portion of the first term finals, and on top of that performing worse than in the mid terms when class E had a handicap.
Brilliant but Lazy: Aside from assassination attempts, he never seems to put much effort into anything, even training. Not that it affects his performance.
Comes to bite him in the ass during the first term finals where he performs badly enough to go from 4th to 13th place in the school rankings. Certainly, he still did great for someone who didn't study at all, but he could have done better and all involved know this.
Broken Pedestal: A teacher he looked up to protected him from the consequences of his Bully Hunting because of his good grades... Until he targeted the wrong person. The pedestal breaking is (very) graphically depicted by the teacher crumbling to dust until only a skeleton remains.
Bully Hunter: It was this hobby of his that landed him in class E when he beat up a top-ranking student in defense of a member of said class.
Cheshire Cat Grin: He's often seen wearing a wide, open-mouthed grin, especially when he's in the middle of ruining someone's day.
Not Afraid to Die: Jumped off a cliff as part of an assassination attempt. He wasn't sure if Koro-sensei would even try to rescue him, and even if he did, if Karma's plan had gone as he intended he would have fallen to his death after killing Koro-sensei. He's developed to become more attached to his life since then.
Oral Fixation: Chews things - fingernails, paper, whatever - when he's seriously upset.
Sociopathic Hero: Unlike Nagisa, he isn't just capable of violence, he enjoys it. A lot. People he targets often end up very badly injured. At least he seems to have a sort of a code.
"The Reason You Suck" Speech: On the receiving end of one, from Koro-sensei, after he gets lower scores than previously on the first term exams. Of course, this is to help him learn and grow, but it was still harsh-sounding enough to qualify.
Master Poisoner: In training, so currently more like "Apprentice Poisoner" at the moment. Homemade toxins a speciality! Needs to work on delivery, though.
No Social Skills: She is awkward, timid and incredibly straightforward. Her method of trying to poison Koro-sensei was to walk up to him and ask him to drink her concoctions. Then, when Koro-sensei offered to tutor her on how to create a chemical mixture that would kill him, she took him at face value. Needless to say, it didn't work.
Shrinking Violet: Although she's slowly coming out of her shell, she's still very shy.
2nd best knife work, boys' side.
The Casanova: He doesn't take much time to find a new girlfriend after getting dumped by the previous.
A beautiful and popular student, said to be the idol of class E. Comes from a conservative, wealthy family, who wanted her to be an ideal Japanese woman. Rebelled against her family by constantly visiting arcades and ignoring her studies, which caused her grades to drop to the point that she was moved to class E.5th best marksmanship, girls' side. Ranked 2nd in school for Japanese Literature.
Gamer Chick: Not just regular games. She wins at Bullet Hell arcade games, while never losing her Yamato Nadeshiko demeanor. It's deconstructed, in that she got so good at video games by shirking her studies to rebel against her parents, and that's how she ended up in class E.
Stepford Smiler: After falling to class E, she became depressed because her teenage rebellion led her to fail her family. Thanks to Koro-sensei she got better.
Yamato Nadeshiko: She is noted for her grace, helpfulness and reliability, and is very popular among the male students. As is customary, she also has some steel to her as well. She was the second student to stand up to Takaoka, after he revealed his true nature by beating up Maehara.
3rd best knife work (tied), girls' side.
Crazy-Prepared: Learning from Bitch-sensei, she carrying around different organizations' badges just in cases.
She-Fu: She put her skills as a former member of the gymnastic club to good use.
Class 3-E's male class representative.2nd best marksmanship, best knife work, boys' side. Ranked top in school for Social Studies, and placed 10th for composite score.
Badass in a Nice Suit: As noted above, his combat skills are exceptional. He's also one of only two characters to wear the full school uniform, with both jacket and waistcoat (the other is Takebayashi).
Finger Poke of Doom: When dealing with four particularly assholish students from the main school, Nagisa, Nakamura and Kanzaki all scare them off by holding pens or rulers against their necks. Isogai does the same thing, but with a single finger.
Hair Antennae: Has them, though he doesn't fit the personality type. His character profile says that people want to rip them out, so if you see him in fanart and another character is near him holding scissors or shears, that's why.
Extreme Doormat: Started out like this, anyway. Has since taken a level in backbone.
Taking Advantage of Generosity: A victim of this. She spent so much time helping another student study (because of emotional blackmail) that she fell behind in her weaker school subjects and landed in class E.
The Mole: Briefly worked as one for Shiro so he could avoid drawing attention with his presence. Quit once he found out just how little regard for class E's lives Shiro had.
Real Men Wear Pink: During the first term finals he gets a perfect score (and is tied for the top rank) in home economics.
Rules Lawyer: Well, it was never stipulated which subjects they should get first in, was it?
Smug Snake: Yup: tends to think himself more important than he is. And, that the best way for a peaceful life... is to bring others down to his own level. Oozes Smug. This may well be in the process of changing a bit since he's taken a level in self-realisation.
Air Guitar: Apparently does this. Offscreen. Behind the school building where nobody can see.
4th best knife work (tied), boys' side.
All Men Are Perverts: So far, all of his noteworthy lines have been expressing this as an opinion. He sees a love of large breasts as a bond between all men, including himself, Koro-sensei and Itona. It's a good thing he doesn't sit next to Kaede.
Fantasy Sequence: Has one where she imagines Koro-sensei and Itona living together as children... in medieval times. They were separated from each other while fleeing an invasion. When asked why only one of them appears human, she Hand Waves it as "a mutation".
Autonomously Thinking Fixed Artillery/Ritsu
Arm Cannon: Several, which she can freely customize inside her body.
Full-Name Basis: Everyone calls her by her full moniker, with a -san for good measure, until they just shorten it to Ritsu.
Matter Replicator: She is able to mold a special plastic inside her body into many different forms, even things like replicas of statues and flower bouquets.
Overly-Long Name: Jiritsu Shikou Kotei Houdai, or Autonomously Thinking Fixed Artillery in English.
Walking Spoiler: Meant to preserve the moment of surprise when she first appears, though she appears so early it may be pointless.
Zettai Ryouiki: Grade A, during the times when her human visual representation is rendered as a full body.
Scarf Of Asskicking: A white, furry muffler. Sometimes he wears it into battle, sometimes he doesn't.
Walking Spoiler: He's a major puzzle piece in the mystery part of the storyline.
The tip top of the student body of Kunugigaoka Junior High. Led by the Chairman's son Gakushuu.
The Ace: The Five Virtuosos are the top in their respective subjects. And come with the requisite ego to match.
Student council president of Kunugigaoka junior high school, the top scorer of the Five Virtuosos who have the highest scores in the school, and son of chairman Gakuhou Asano. He is every bit as domineering as his father, but lacks his sense of greater purpose. Before the first term finals, he leads class A, comprised of the school's top students, in a massive group study session to ensure class E cannot upset the school's established system at his father's behest.
The Ace: Ranked either first or second in all his subjects during the Final Exam arc.
Antagonistic Offspring/Eviler than Thou: His relationship with his father is basically this. He wants to keep his father like a pet, while his father intends to make him a corporate slave for the rest of his life. One has to wonder what the mother is like.
Break the Haughty: Hit with this in chapter 54, with his father rubbing salt into the wound.
Even Evil Has Standards: On the wrong side of this trope. Even his fellow Virtuosos, none of them pleasant people, think of him as black-hearted.
Last Name Basis: With his own father, though this isn't too uncommon in formal settings.
"The Reason You Suck" Speech: Receives one from his father in chapter 54 after losing the bet with Class E. Gakushuu's father mocks his plan to turn him into a pet when he couldn't even win against people his own age.
The Sociopath: He's inherited all of the traits his father displays, in particular the charisma and callous manipulative behavior.
One of the Five Virtuosos, ranked second in the school, specializing in social studies. As head of the broadcasting club, he had a few cameos before being formally introduced. He was one of the speakers in the May school assembly, and the announcer in the exhibition baseball match.
Mouth of Sauron: Though it's not any kind of official capacity, most of the time when he appears he's the one implementing Asano's vision of the school by inciting the other students to mock class E, since the chairman himself doesn't often involve himself in the day-to-day lives of his students.
Smarmy Host: Makes constant obviously disparaging comments about class E in his speeches.
Younger Than They Look: In his first appearance, in chapter 11, if you didn't notice he was wearing a student uniform you might think he was a member of the faculty.
One of the Five Virtuosos, ranked third in the school, specializing in Japanese.
One of the Five Virtuosos, ranked fifth in the school (Karma took the forth place ranking), specializing in science. Prior to the first term finals, appeared only in Terasaka's pre-class E flashbacks.
Gonk: With his extremely crooked teeth, bizarre eyes and grotesque expressions, he really sets the bar for ugliness high.
Jerkass: Beyond the normal non-class E unkindness, he is verbally abusive even to members of his own class while he tutors them.
Pride: Has a strange, almost obsessive vanity. When sitting under an awning in the rain he remarks, apropos of nothing, about what a sense of superiority it gives him to be in the only dry area.
Kunugigaoka Junior High School Other
Captain on the baseball club, able to pitch fastballs on the level of pro players.
The Ace: How he sees himself and his team members, who all excel in both military arts (sports) and literary arts (study). He refers to them as chosen ones.
Blunt Yes: To when Karma questions whether he really is a chosen one.
Friendly Rivalry: With Sugino, with a power vs. technique dynamic. He acknowledges it after class E wins the exhibition match.
Heel-Face Turn: The first main school student to openly help class E, even if only in a small way. Then again, the baseball club was always less malicious towards class E than the rest of the school. They mostly limited themselves to a few insensitive comments and being typical arrogant jocks.
I Always Wanted to Say That: He always wanted to introduce a group of people like an over-the-top announcer. He gets his chance with the Five Virtuosos.
Large Ham: He really enjoys being overly dramatic.
A girl from the main school. Has or tries to have at least three different boyfriends over the course of her short appearances, mainly just for the sake of having one.
Bad Liar: Lies often, about anything and everything that may cause her embarrassment. It's always obvious when she does, but Seo at least is perfectly happy to let it slide.
Bitch in Sheep's Clothing: Though she tries to pass herself off as merely playful, her spite for everyone who isn't useful to her is clear.
Triang Relations: With Maehara as A, her as B and Seo as C, a type 4... Until the rest of class E decided to get involved, at which point it became nothing.
Your Cheating Heart: Maintains multiple boyfriends at once as a matter of convenience. When two of them find out about each other, she casually dumps the more disposable one (class E's Maehara) on the spot.
Even Evil Has Standards: While he is not above hiring teachers who use fear to control students, he draws the line with teachers using unnecessary violence as Takaoka finds out when he is fired. However, his objection had more to do with professional standards than moral ones.
His objection wasn't even with Takaoka's use of violence as a teaching method. While he disapproved of it, the reason he stepped in was because Nagisa beat Takaoka in their fight, which meant the class would never be afraid of Takaoka again.
Foil: He and Koro-sensei contrast each other greatly. Where Koro-sensei is a monster intent on destroying the world, Asano wants to improve the world through education. Yet strangely, Koro-sensei is goofy, but kind, while Asano is strict and incredibly cruel.
Follow in My Footsteps: His Son is basically like him. They have a ... disturbing relationship, with one intent on keeping the other as a corporate slave and the other treating his father like a pet.
Manipulative Bastard: Anything he can do to ensure that his system works will be done, from personally teaching the content of an upcoming midterm to all students except Class 3-E to hiring a Sadist Teacher to make sure Class 3-E's grades drop dramatically.
And when said Sadist Teacher failed to live up to expectations ie. beaten by Nagisa, he swiftly ejects them.
Not that ironically: the guy was considered rather abrasive and quite a nasty piece of work both in contemporary sources and since. That he got judicially murdered wasn't that much of a surprise, considering the stuff he pulled. The honor doesn't lie in the 47 defending the memory of a just man, but keeping their word and allegiance beyond his death.
No Sense of Personal Space: Goes forehead-to-forehead with the coach of the baseball club (pretending to check for a fever) when threatening to fire him because class E is winning the exhibition game against them.
The Sociopath: He has not even the slightest shred of remorse or empathy for the students whose lives he actively tries to ruin. He also has the superficial charm and manipulation ability aspects of the disorder down pat.
Well-Intentioned Extremist: His system intends to ensures that 95% of the students become highly successful in their studies... by treating the other 5% like absolute garbage. Considering his sociopathy, YMMV as to whether this is actually well intentioned, or if it is simple a bid for glory.
The Extremist Was Right: While his methods are severe, and despicable, he has, in fact, turned his school into one of the most prestigious in the country, and the vast majority of his students are practically guaranteed to move on to bigger and better things. It is also worth noting that, while he does not discourage the mistreatment of Class E by other students and teachers, he also does not officially encourage it, either. The entire faculty and student body perform these actions of their own free will, and there is no official reward for doing them, nor is there any official punishment for not doing it, or for helping members of Class E. Call him evil, a sociopath, a sadist, he is all these things, and probably worse, but he created a system that works, and works well, so even if it means that 5% of his student body will be completely miserable, the other 95% will thrive. His only real offense against his students is working to ensure that any who fall into Class E never get out.