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Neuro and Yako
VA: Takehito KoyasuA powerful demon from hell with a taste for mysteries. He acts as Yako's assistant and uses her to find food for him; he's the one who solves all the cases, but gives the credit to Yako. Being a demon, he's as one expects - cruel, sadistic, mysterious, and an embodiment of the Troll trope. His care for humans, during the start of the series, extends only enough to think of them as food - his character arc, as subtle as it is, is realizing humans can do so much more and earns respect from demons for being strong.
- Animal Motif: He uses small creatures, usually bugs (amoebas, woodlouse, worm, etc.) to describe Yako. When his respect for her goes up, he changes what he calls her.
- Bad Boss: One of his trademarks, but Sicks has him beat in outright cruelty.
- Berserk Button: Neuro prefers mysteries behind how people go to great length to kill others for the pettiest of reasons. However, of you kill pointlessly like Sicks, he will make sure you suffer.
- Big Eater: Despite the fact he keeps calling Yako a pig, he is no better than her when it comes to food. It's just that his food is harder to find than hers.
- Bishounen: His human form.
- Blatant Lies: He is Yako's "assistant" and is "tortured often by her" and is often "forced to do things he doesn't like". Add in the fact no one notices him picking on her and a lot of people do fall for it.
- Blue and Orange Morality: Don't try to use human's reasons with him. He's a demon from hell, after all.
- Body Horror: One of his abilities is causing illusions to be this.
- Cast from Hit Points: He slowly becomes weaker as the story progresses, losing all of his energy from use of his strongest weapons.
- Character Development: As time goes on, he becomes more and more invested in humans, showing interest that extends past them being his source of food. He also grows to respect Yako, Godai, and the police department.
- Crutch Character: A unique case in a Shounen series, instead of getting more absurdly powerful as time goes on, it's inverted as the use of his powers makes him gradually weaker so he relies on others instead.
- Decoy Protagonist: In the end, Nōgami Neuro is about Yako's development into a detective.
- Dissonant Serenity: He's almost always composed, even if he's losing.
- The Dreaded: To other demons. He also counts to the Police Department in the earlier chapters of the manga - they blame him and Yako for lowering the status and trust for the police department, as well as taking away some of their high profile cases and easily solving month or year-old events within minutes.
- Evil Sounds Deep: Played with. As Yako's "assistant", Neuro has a much lighter voice. While being the investigator, he has a deep voice.
- Good Is Not Nice: Played with. Despite his love for violence, he's generally content with just trolling people (for all the abuse he gives Yako, he never actually hurts her and it's only Played for Laughs), and go so far as to say that he's a pacifist and would prefer to avoid fights whenever possible. However, he's very much capable of dealing serious damage to his enemies if he wants to. A prominent example is DR, who angered Neuro after killing thousands of innocent humans, so Neuro retaliated by gleefully torturing him to the point of a Villainous Breakdown, cutting off both his hands and forcing him to beg for forgiveness, before he finally got tired of playing with him and left him for dead at the river. And he was enjoying himself the entire time.
- Hair Decorations: They're actually batteries that store demonic energy for later use, but the function just the same. He even gives one to Akane, which she wears at the very end of her ponytail. By breaking or devouring them, he can use the sealed energy, but he prefers to use an invention or two and tying his hair back than do so.
- Humanity Is Infectious: A trope that's played with through the series. Neuro looks down on humans, often insulting them and he treats his assistants like servants, with the exception of Akane. However, as the series progresses, he becomes nicer and slowly more interested in humans; however, this can be inferred for simply liking how Yako and Godai grow.
- Humanoid Abomination: His demon form: A parrot/tucan-headed creature with horns. However, the form is rare to show up because Neuro simply doesn't need to use it, and the only time we see it frequently is when he's devouring the mysteries.
- Meaningful Name: "Neuro-" is a prefix, relating to nerves, while "Nōgami" is a Japanese word meaning "Brain Eater". Most of his tools affect the nerves or senses and he's incredibly smart.
- Multicolored Hair: Brown and blonde.
- Not So Different: Throughout the series, Neuro comments on multiple things that happen in the human world that also happen in the underworld. Problem is, the trope is heavily subverted:
- For instance, the sun is a giant demon that sleeps in a volcano-looking structure and, if demons want there to be sunlight, they have to go lynch the sun and force it out of bed. Furthermore, "solar-powered cars" are monsters that forcibly piggyback the sun, making its day even worse.
- A standard soap opera for a demon is that everyone dies within the first five minutes and the rest of the show is spent filming the corpses. For two hours.
- Hot springs are made out of magma.
- This one is inferred: To cheer on a soccer team, one must dress up like you're performing a curse ritual, get some pikes with voodoo dolls pierced on them, paint a skull like a soccer ball, and use both a katana and a trumpet to cheer.
- A "desk" is a giant dinosaur-like creature with a head for a desk. It will rampage if anything is put on its head.
- A "good person" in the demon world is someone who makes wounds impossible to recover from.
- Neuro does have a listed birthday: according to his bio, it's the 344th day of the 16th month.
- Capybaras are, in the demon world, unicorn beasts that are twice the size of a standard city.
- The color "pink" is known as "human flesh".
- One Head Taller: He's 6'1~7'3, according to his Bio; the only one close to either of these measurements is Tsukushi, who stands at roughly six feet.
- Pet the Dog: At the very start of the manga, Neuro is somewhat polite towards Yako while solving the murder of her father. Yeah, he's still Neuro, but he shows a bit of care towards Yako and even asks if she's happy once the murder is solved. Interestingly enough, he shows similar moments to this as the manga goes on, expressing care in his own ways when Yako is in severe danger.
- Power at a Price: In order to use his powers, he needs energy from the Demon World, which he can only replenish through solving mysteries or absorbing miasma.
- Power Degeneration: Unusually for a Shōnen series, he gets weaker as the series goes on.
- Swiss Army Weapon: Has a full pocket of this. Not to mention he also has access to royal/demon emperor's weapon.
- Troll: The biggest troll. Famous incidents are: putting super steroids in Yako's gift chocolate on Valentine's Day, setting up traps for kicks, using Yako as a weapon, releasing demonic fish within hot springs, stealing Yako's wallet and going home by himself while leaving her several long miles away from home, and getting Yako and Godai to deactivate a bomb by themselves despite being fully capable of doing it himself.
- Wall Crawl: He's capable of simply floating and flying, but his entrance and introduction to Yako had him standing on her ceiling. He can also stand on walls and crawl up and around any kind of surface.
VA: Kana UedaThe "investigator" for Neuro's company, she's an ordinary (at first) high-school girl whose father was killed in the first chapter. She acts as Neuro's cover but as time passes, eventually develops her our skills. The straight-man to Neuro, Yako shows heart and goes along with Neuro and his detective agency (whether she likes it or not) to assist in solving crimes. Where Neuro is cold, Yako is kind, and though she becomes a little cynical and callous because of everything she's one of the nicest characters in the series.
- Big Good: The nicest, sweetest character around that's involved with the plot and isn't dead.
- Big Eater: She has a huge appetite like most Shōnen heroes. She ate an entire buffet in 30 minutes and she can devour a giant fish in seconds. When X/Sai kidnapped and used the Electronic Drug on her, she oddly lost this quality for a time.
- Character Development: At the beginning of her time with Neuro, she feels more like a doll, since Neuro is using her as a cover to solve cases. As time goes on, she begins to become stronger and starts begins talking to associates with the victim and sometimes the criminal to help calm them down, and she even ends up befriending Aya Asia. At the end of the manga, we see Yako taking up a job as a negotiator.
- The Charmer: Eventually becomes such a silver tongued woman that she could talk a bunch of armed terrorists into cheerfully surrendering themselves while asking to meet her again.
- Evil Mentor: She naturally attracts these. With the exception of Sasazuka, everyone who's given advice to Yako is either a former criminal, a monster in two different ways, or isn't exactly full of justice themselves.
- Extreme Omnivore: As a direct side effect, Yako is also able to eat a number of items that people would normally shy away from. Such examples include eating half a bag of marbles thinking they were hard candy, eating part of a giant river fish raw despite its muddy flavor, and attempting to eat raw oysters while still underwater. She even ponders that she could eat concrete if it were cooked in butter and soy sauce.
- Fusion Dance: With Akane to grow long hair, which is usually used as a disguise or a weapon.
- Giving Someone the Pointer Finger: Neuro has her do this to point the criminal out, possibly as a spell to channel the mystery when it appears.
- Hair Decorations: Her demon-grin hair clips, which come in three colors, implying it's something she bought: red (which she always wears), blue, and white. At one point, when Sai has copied Yako and used the Electronic Drug on her, Neuro uses them to decide who is the real Yako.
- Hair of Gold, Heart of Gold: She shows kindness a majority of the time, even to X.
- The Heart: Although she starts out as just a mask for Neuro, Yako develop skills in reading people early on, and appreciating who they are. Though Neuro's skills are what bring cases to a close, Yako's empathy often brings out key points Neuro would overlook.
- I Will Wait for You: After Neuro goes back to hell.
- Long Lost Sibling: X/Sai, anime only.
- Kid Detective: Only a fake one at first, but she learns over the course of the series. However, Neuro usually solves the case for her.
- Kid with the Leash: In name only, as Neuro hired Yako as the investigator to be "the human everyone trusts", i.e. a spokesperson to make himself inconspicuous.
- Plot-Triggering Death: Her father's death lead Yako into wishing to find his murderer. That was Neuro's cue to step in.
- School Uniforms Are the New Black: Even on the job and not in school that day, she wears her school outfit.
- Sherlock Scan: Initially it's faked by Neuro, but she gets better as the story goes on.
- Supreme Chef: Since her mother is a terrible cook (metal alloy ''chocolate hearts'', creating a nitrogen bomb while baking a cake, so on), Yako knows a share of cooking-related information.
- Took a Level in Badass: From a somewhat-naive school-girl to a world's famous negotiator.
- When she and Akane fuse into a long haired version of herself, they're able to manipulate their hair to do things.
Yako's Detective Agency
VA: Hiroyuki Yoshino (anime), Kishō Taniyama (radio drama)He worked for a small finance house with criminal connections until his boss was killed. Per to Neuro's agreement, he and his fellow employees left, but only he was called back later to chase away cameras. He eventually moves up into the world, taking control of an information company who had approached the Detective Agency for publicity, but he remains under Neuro's thumb.
- Badass Normal: He beats up trained body guard and then there's the True Blood arc.
- Bullying a Dragon: And, sadly, the man often bullying said dragon is a greater beast...
- Butt Monkey: Neuro constantly abuses him if not more so than Yako herself.
- Foil: To Sazasuka; both assist Yako from case to case, but Godai's high blood pressure and Yakuza-attitude got on the nerves of Sasazuka's low blood pressure and calm attitude. This is seen during Yako's case with the murder of a toy company's president, but by the end they pull together and defeat the Villain of the Week together.
- Hot-Blooded: Very emotional and straight-forward.
- The Precious, Precious Car: Neuro completely wrecks Godai's brand new car while chasing after the Third Sphinx. To apologize, Neuro gets him a used pick-up that's falling apart.
- Red Oni, Blue Oni: Red to Sasazuka's Blue.
AkaneHair of a corpse in the wall of the office Neuro took over. We still don't really know whether she is the soul of the corpse controlling the hair, or the hair itself that comes to life. She is the Agency's secretary, a really damn good one at that.
- Fusion Dance: After being given one of Neruo's Hell Batteries, Akane has the ability to come off her corpse in the wall and attach herself with Yako's hair. She noticeably grows longer and her color changes to follow the hair of the person she attaches herself onto. In this state, she can manipulate herself like a weapons. She cannot stay attached to Yako for too long though, as the imbalance in demonic energy between the both of them, and the fact that Akane is "dead" and Yako alive, would eventually cause them to switch personalities.
- Prehensile Hair: For some hair of a corpse, she can do a lot of things. That includes making tea and read French, too.
- 10-Minute Retirement: When Yako decides to leave the agency, Akane refuse to work for Neuro. She begins working again when Yako returns.
Tokyo Police Department
VA: Koji YusaOne of the two police officers assigned to solve the mystery of Yako's father's death. Later become one of Yako's best allies, partly because his partner at the time turned out to be the murderer. Cool, collective but really weird in his own way. He lost his family to X and was one of the first to be hit by him, but later on it's revealed this was Sicks' doing.
- Big Brother Instinct: Subtlety being this toward Yako (Knowing that Yako is competent but still wished her to stay away from the Histerrier and the Head-Cutting Hairdresser) as his sister was the same age as her when she died. As such, he looks after Yako in his own ways, as if to repent for failing to protect his sister.
- The Dreaded: Just hearing his name can make a very powerful criminal shakes like crazy and warn Godai to not to go near him.
- Empowered Badass Normal: He has skills "not taught in the Police Academy", and there's rumors of him having trained through the Black Market and other underworld powers.
- Guardian Entity: Tsukushi, as well as a few other characters and Sasazuka's actions themselves, imply that Sasazuka watches Yako very carefully and often forces her away from the crime scene because she reminds him of his little sister. Made worse by the fact that Yako is currently around the same age as Sasazuka's sister when she died.
- Go Out with a Smile: Directed at Yako after Sicks shoots him dead.
- Jerk with a Heart of Gold: He is merciless toward Jun, but he does care about the guy.
- Nerves of Steel: Shows only slight concern for things that everyone freaks out about. Case in point, seeing X for the first time and coughing up blood while in the hospital (and having done it enough to know why he's coughing up blood).
- No Sense of Humor: He defines the word "calm".
- Plant Person: It's been mentioned that Sasazuka is basically an office plant. When he was poor, he had survived for two weeks on alcohol, sunlight, and salt. His regular sleeping time is 40 minutes, not a whole lot fazes him, and above all, he generates oxygen for the fish bowl sitting on his desk. He can also regulate temperatures and he isn't seen moving in an awful lot of panels.
- Sempai/Kohai: While never calling anyone "Kohai", Jun almost always refers to Sasazuka as "Sempai". Later, when Sasazuka dies, Jun takes up the title of "Sempai" in his partnership with Todoroki.
- Smoking Is Cool: Even in a hospital.
- Spit Take / Eye Take: Had a spit take when Yako appeared crashing Aya Asia's concert, then later had an eye take when he saw the commercial she was in at the beginning of Chapter 39.
- Suicidal Overconfidence: He went into fighting Sicks without knowing about Xi, the reformed Sai, let alone Sicks' true powers
- The Stoic: He catches on very quickly to how bizarre the cases get with Neuro around.
- What You Are in the Dark: Vicious, sadistic, and swallowed by revenge.
VA: Kosuke ToriumiSasazuka's partner and looks up to him greatly. A huge Otaku, Jun's apparently kept on the team only to provide a balance for Sasauka.
- Butt Monkey: His models and smaller desires, like getting autographs or taking pictures, are often destroyed by Sasazuka and later Shizuka. Played with, because some of the time it's legitimately things he shouldn't be doing (like, again, getting autographs).
- Chekhov's Hobby: He's always seen building Gundam-like models or ships/planes in the background. Because of this, it's shown once and can be inferred that Jun is very good at rebuilding evidence, which may be part of the reason why he's kept around and allowed to do his hobby at the task force; the more he learns about model building, the more he's able to reproduce evidence even when it's destroyed.
- Eye Take: His main reaction face; if he's part of a joke, it's likely him doing an Eye Take.
- Fanboy: He looks up to Sasazuka and he tries getting Aya's picture and autograph.
- Funny Background Event: The largest part of Jun's character seems to be making Sasazuka comedic, from having the older detective break his things to lighting an autograph bored on fire and attacking Jun while in the middle of a phone conversation. He also doesn't seem to be enjoying his time during the HAL arc, since whenever seen he has a weary expression painting his face.
- Nice Guy: So much so that he ends up telling Yako the information about dangerous suspects despite Sasazuka wanting to leave her out of it. Despite his incompetency, the Police Department keeps him hired because he balances out not only Sasazuka, but some of the other members as well - as Sasazuka himself put it, "you need all kinds of people in the Police Department".
- Otaku: He's often seen building models of robots or vehicles while on duty.
- The Rival: Views Shizuka as this, largely because he believed he was in danger of losing his job as a policeman period.
- Sempai/Kohai: Calls Sasazuka "Sempai" and later names himself "Sempai" when Sasazuka dies.
- Spell My Name with an "S": In-universe example, his name at birth was "Shun", but it was spelled wrong into "Jun" on papers, so he sticks with it.
- Took a Level in Badass: After the death of Sasazuka, Jun abandons his more childish attitude to become a little more serious, intending to pick up where Sasazuka left off.
VA: Hidenobu KiuchiThe chief of police, Usui is a strict boss who desires nothing more than perfection. He was originally Sasazuka's rival, and he seems to hate everyone but Tsukushi.
- Cuteness Proximity: Had a soft spot for cute things (like panda and flowers).
- Friendly Rivalry: He competed with Sasazuka for high grades when they were in collage, but at the same time often gambled with him.
- Not So Above It All: He tries to be serious most of the time but there are moments where he's just as bad as others (like spending the whole day just to listen to the sounds inside seashells)
- Sore Loser: While Usui did, in the end, get higher grades than Sasazuka, he only did so because Sasazuka's family had died and, in response, Sasazuka lost all energy for life. Usui's never forgiven him for abandoning their rivalry, thus why he treats Sasazuka terribly and the detective doesn't mind.
- Took a Level in Badass: As Neuro gets weaker against Sicks, Usui organizes the police against the New Breed. They take down several and are actually essential in stopping it on a systemic level while Neuro takes out individual leaders.
VA: Hiroki YasumotoA quiet man who threatens everyone he comes in contact with without really trying, Tsukushi is there to assist Usui. Also knew Sasazuka and Usui from their collage days, but he wasn't as close to either of them back then as Usui was to Sasazuka.
- Nice Guy: He's actually rather friendly, despite his quiet attitude.
- Trademark Favorite Food: "Ginza Bulgarian Commute Lash" yoghurt. He apparently eats one every day before going to work.
- Weaksauce Weakness: He's allergic to chocolate, which causes him to look "like an angel who's been shot down". It's apparently divine looking.
Shizuka TodorokiA detective who never appeared in the anime, she's recruited and added on to be Sasazuka's partner during the New Bloodline arc. A serious woman who's the complete opposite of Jun in all aspects except looking up to Sasazuka, she follows her job to a T.
- Chekhov's Gunman: She's called onto the scene before her proper introduction to demonstrate that a grown woman, even on the Police Force, couldn't push someone over a high rail and off a tall building.
VA: Nozomu SasakiA 19 year old hacker who works for the Police Department. Very important during the HAL arc, Higuchi assisted in revealing information about, decoding, and curing the Electronic Drug. He acts almost his age, but he's incredibly playful.
- Abusive Parents: Shortly after he was born, his parents became addicted to an MMO which came to dominate their lives, leaving Higuchi to buy his meals at the convenience store and to play the game with them. Their house is a mess from what we see of it. They committed suicide after he forced their MMO to crash, unable to live without it.
- Brainwashed and Crazy: HAL manages to control Higuchi and forces him to become the last Sphinx. He wasn't entirely Brainwashed, however, which Yako found out when he broke into a guilt-filled rant about his past.
- Cool and Unusual Punishment: Because he didn't have a good relationship with his parents, Higuchi doesn't know a single thing about Japanese Politeness. As such, Usui, in order to keep him from making his own Electronic Virus, forced Higuchi to be strapped to a chair and watch twelve hours non-stop of videos on etiquette, which he called the "anti-virus". After making a weaker Electronic Drug to brainwash a supervisor into being laid-back, Higuchi suffers twenty-four hours of said tapes and completely forgets how to make the virus.
- He's also hard-wired to go into Sincerity Mode when surprised, thanks to the tapes.
- The Cracker / Playful Hacker: For three days, the Police Department website was replaced with the "sakuradamon Department Store", with each department and member replaced with a lookalike shop and employee. The Investigation department was made into the Fundoshi Shop, and Sasazuka recalls Ishigaki being turned into the "Fundoshi Wine Steward". The Police Department retaliated by allowing it to continue until they could absolutely catch Higuchi.
- Everything Is Online: He can even hack traffic lights.
- Goggles Do Something Unusual: His glasses, which he usually wears on his forehead, are capable of preventing him from seeing the true effects of the Electronic Drug.
- Grey and Gray Morality: While not evil, he's able to bring up morally questionable things and press ethics.
- It's All My Fault: His parents committed suicide when their favorite MMO, their life, was destroyed after Higuchi hacked it. He blames himself for their deaths, as he only wanted them to pay attention to him.
- Purely Aesthetic Glasses: He's farsighted, but he never uses his glasses.
- Recruiting the Criminal: Continuing the incident involving the police website above, the Police believed that, if Higuchi was arrested and put into jail, he'd be hired by companies to do far worse things. As such, the Police hired him first and allowed Usui to watch over him.
VA: Romi ParkX, pronounced "Sai" for "Kaitou Sai" or alternately "Phantom Thief Sai" or "Monster Robber Sai", is a world-renown thief. Known for killing his victim by shredding them up and creating a glass red box with what remains of their body inside and then stealing one object from their house, X becomes becomes Neuro's greatest enemy. His shape shifting abilities are powerful and grow moreso over the course of the series, but they also cause him to lose his memories frequently. As such, he has no clue as to his origins.
- Affably Evil: He's very laid back and childish, even when killing a gorilla. The only time he loses his cool is when Neuro manages to best him in combat, and when learning Neuro is technically dying.
- Big Bad: Of the anime overall, and the first major one in the manga
- Cain and Abel: The Cain to Yako's Abel, anime only.
- Chekhov's Gun: The death of Sasazuka's family is always regarded as X's fault. To tell the truth, it was Sicks. X just found the wooden boxes the family members were turned into, complained how you couldn't see inside, and got his idea for his M.O.
- Dissonant Serenity: Very laid back and easygoing for a mass murder
- Even Evil Has Loved Ones: X has this for Ai, leading to The Lost Lenore when Sicks has her killed
- I Am a Monster: Regards himself as a monster due to his shape shifting abilities. It's because of this mindset that he desires to see Neuro's insides, as he feels they're kindred spirits.
- Kill and Replace: His modus operandi, if his victim is sufficiently interesting to him. After a sufficient amount of time, anyone X has replaced will suddenly reappear in his typical glass cubes, and he'll be off unto his next victim.
- Knight of Cerebus: Gave the story an overarching plot and a consistent villain.
- Leitmotif: Entitled "Sai".
- Loss of Identity: His main personality trait. Everything X does is to understand who he is, from his habit of creating red boxes to trying to murder Neuro. And, unfortunately, when he finds his answer, he faces the same problem over again but isn't aware of it due to Sicks' manipulation and memory wiping.
- Multiple-Choice Past: His anime and manga back stories are different.
- In the Manga: He was created as a female clone of Sicks, leader of the New Bloodline. As the Eleventh clone, she was called XI and was released shortly after the death of Sasazuka's family to gain experience. However, because her shape shifting abilities removed her memory, she soon forgot her gender and history and became the boy known as X. Discovering the remains of Sasazuka's family, who Sicks killed himself and stuffed into wooden crates, he mourned on how you couldn't see inside them, which formed his M.O. as he had lost his memory at this point of what he was. From then on, with Ai's encouragement, he set off killing and disguising himself as others to find out who he was inside, leading to present day.
- In the Anime: X was born to Seiichi Katsuragi, Yako's father, and a witch named Seiren. Being able to shape shift due to a superior form of cancer at the price of losing his memory every six months, X set out to find out who he was before he lost all of his memories.
- No Pronunciation Guide: The reason his name is pronounced "sigh" instead of "ecks" and despite his name being consistently spelled "X" is because his name was first called "Monster Robber Xi" by a foreign media: X for the unknown, I for the invisible. When pronounced in English, it becomes "Sai". "Xi" also stands for "11" in Japanese, see the last trope.
- For those confused, by the way, as to why "X" = Unknown, it traces back to language. However, there's about three roots:
- Arabic into Old Spanish: The word "šay'", pronounced "shey", means "something" in Arabic. When Spain scholars were tasked to turn Arabic into Old Spanish, they found they couldn't directly translate "šay'" due to the fact that the hard "sh" sound it needs didn't exist in their language. To get around it, they translated "šay'" into "xei", which became shorted to the letter "X".
- Greek: There are two Greek letters that use X. "Xi", which is pronounced "sai" in English, and the letter Chi which is rendered as "X". The Greek word "xenos" means "unknown", more or less for strangers or foreigners than the actual unknown.
- Latin and math: Latin actually has its roots tied directly to the Arabic into Old Spanish written above. When the Arabic word for "something" became "x", the Latin language took it up and used it in Algebra to denote unknown numbers.
- For those confused, by the way, as to why "X" = Unknown, it traces back to language. However, there's about three roots:
- One-Letter Name: Really it's two letters, as described above, but his name is always rendered as X.
- Starter Villain: The recurring villain in the series when it was Monster of the Week beforehand, he ends up revealing the true colors of the manga before HAL ever gets started and he creates a lot of mysteries in the narrative-perspective.
- Stupid Evil: He plays the role of an idiot villain when he's not in the middle of a crime, with Ai being his straight-man.
- Voluntary Shapeshifter: Initially he was stuck to transforming into humans. However, the longer he lives, the stronger his powers become, allowing him to shapeshift into animals and even mutate his body into having extra limbs and strength to match Neuro.
- White Hair, Black Heart: Played with. He shows compassion to his assistant, Ai, as well as to Yako in the late manga and anime and to Yuka Eshiya. However, he can quickly become homicidal and he kills without mercy.
- You Are Number 6: His name, X, was originally XI, the Roman Numeral for Eleven; he was the Eleventh clone of Sicks.
AiX's partner in crime, Ai is usually in a servant/straight-man relationship with him. We say "usually" because her role changes from day to day, depending on who X is impersonating. It's because of Ai that X is known as a thief, but she's stated that her house is becoming filled with "B-grade goods" like wooden bear statues ever since X gained an interest in Neuro. Before becoming Ai, she was "Plane Crasher Imina" who bombed or poisoned planes. When the New Bloodline arc began, Ai was killed by Sicks and X was captured to become XI.
- Humans Are Average: Ai believed that every human is exactly the same, inside and out. This actually greatly upset X when they first met, but this view changed after X murdered her backstabbing comrades in front of her. After seeing him in action, she swore to X that, if he wanted to see her insides, she also wanted to see who he was.
- Improbable Age: She's 25, despite looking more along the lines of Yako's age range.
- Jack-of-All-Stats: Her specialty is literally "everything and anything".
- Kid with the Leash: Her very straight and orderly attitude functions well for X.
- Meaningful Name: She chose the nickname "I" for "The Invisible"; the servant who's always there beside X, but never seen. "Imina" is a Japanese term for the personal name of someone dead.
- Punny Name: "Ai" is the Japanese word for "love".
- Nerves of Steel: When she first met X, she was only surprised about his shape shifting.
- Straight Man: To X. She's probably the only person alive who could be X's straight man.
- Unholy Matrimony: Technically with X as, depending on the day, Ai can be X's master or lover.
VA: Minami TakayamaA singer whose voice can reach into people's hearts, move and even control them. She was uncovered by Yako and later become one if her greatest allies.
- Card Board Prison: Her prison is quite good and secure to other humans, but to Aya, the only reasons she hasn't get out yet is because she want to stay. If she decides to leave, Aya can just walk straight out of the front door, singing to force everyone to clear the way. Unlike most examples though, the one time she left on her own accord, she came right back in and allowed her sentence to be increased for it.
- Evil Diva: Not really evil, but she will kill you if you make her love you too much.
- Heel–Face Turn: After Yako solves her case on-stage, and reveals Aya's motivations for doing so, Aya willingly turns herself over to the police. She starts to reform in her time in prison, and becomes Yako's ally.
- The anime changes the scene somewhat, however, making Yako's reveal cause the "puzzle" Neuro feasts on the disappear...somehow.
- Love Makes You Evil: The inversion is her main motive. She felt love weakened her; so killed everyone who loved her and that she loved. At one point, she even tell Yako not to make her (Aya) love her too much or she will have to blow Yako's brain out with her voice.
- Only Sane Woman: In the group after her Heel–Face Turn, and is among the sanest enemies Neuro and Yako had faced.
- Took a Level in Badass: Before she was incarcerated, Aya needed to feel a sense of loss to influence others. Once Yako put her soul and mind to rest, her voice becomes nigh on a force of nature, influencing the guards at her jail, officers of the state, and even insects and plants. The only reason she doesn't control the entire building is simply because she doesn't want to.
- In a sense, she also inspired one in Yako, showcasing the start of Yako's abilities to understand people.
Eisuke Harukawa / Electronic Person HAL
VA: Masane TsukayamaHarukawa was a neurologist, who cloned himself to create HAL; a super advance A.I who plotted to take over the world with an Electronic Drug, which brainwashed the masses via hacking televisions and computers to display the drug. While Eisuke was killed when HAL revolted, HAL himself was later taken down when Neuro trashed his defense system and devoured his mystery, and then uninstalled by Yako.
- A.I. is a Crapshoot: Played with. The original HAL turns out to an Anti-Villain who wanted to revive his lover, Setsuna, but the second one was definitely this.
- And I Must Scream: HAL is trapped in one, the more one thinks on it. He's bound to follow Harukawa's goals in recreating Setsuna, even though he knows, even with all the resources in the world at his disposal, the chances of him succeeding is nigh on impossible. He has no option to stop.
- Arc Villain: Of the HAL Arc.
- Arc Words: "Life between zero and one."
- Big Bad: The second one in both the anime and manga.
- Freudian Excuse: Setsuna's death at the hands of her degenerating mind, which is later revealed to have been caused by Sicks, is what drove Harukawa to find a way to bring her back
- Gone Horribly Right: HAL, as defined by Harukawa.
- I Cannot Self-Terminate: Though HAL can allow others to terminate him, Harukawa never thought of allowing HAL the option to do it himself.
- Leitmotif: Hinted at. In the manga, one of the novels had a picture of Harukawa and Setsuna standing in the filed they had outside Harukawa's original lab with the song title Equal by ACIDMAN written below it.
- Mad Scientist: Harukawa.
- Mercy Kill: What brought him to kill Harukawa, knowing their goal was nigh on impossible no matter the resources they acrued.
- Necromantic: Both Harukawa and HAL wanted nothing more than to see Setsuna again, their goal being to recreate her digitally, in her entirety.
SicksThe leader of a group of super humans, Sicks plans to wipe out most of humanity to make way for the New Bloodline.
- All Your Powers Combined: He has all of the Five Fingers' abilities
- Apocalypse Hitler: Intends to wipe out humanity for his own True Bloodline to flourish; basically Fantastic Racism Up to Eleven.
- Bad Boss: Up to Eleven being a Torture Technician, it's very slow and painful when you fail him.
- Big Bad: Of the final arc.
- Bloodbath Villain Origin: Several, killing the other infants at his hospital after birth, killing his own parents when he was five and killed Sasazuka's family which is later blamed on X.
- Blow You Away: Can manipulate people with his own Evil Intent along with Genuine's manipulation of the air
- Blue and Orange Morality: His plan to destroy humans is not based entirely in prejudice, but rather a natural instinct of evolution to wipe out the other species occupying an niche in the environment, similar to how humankind wiped out its simian relations
- Body Horror: Has metal injected inside of his body due to having genetic memory of how to perfectly smith metal to be an effective weapon.
- Bookends: He makes his appearance by leaving on an aircraft he is finally killed by his own aircraft
- Card-Carrying Villain: Up to Eleven, and if not the darkest take on this trope in manga history.
- Catch a Falling Star: Neuro uses an aircraft to catch him - trick is, the aircraft's the killing moment.
- Chaos Is Evil: Intends to disrupt the order of things by killing off all humanity, which the traditionally manipulative Neuro dislikes.
- Code Name: Sicks is an alias, his real name is Jody Tubulik
- Cold-Blooded Torture: Does this to his victims and those who fail him.
- Creepy Child: Killed his father at the age of five.
- Cruel Mercy: Why he spares Yako after killing Saszuka in a truly horrible way, especially right after this, she learns that Fumio Honjou was The Mole responsible for the information leading to Sasazuka's death, he undergoes some severe Sanity Slippage, showing a truly disturbing Nightmare Face then finally committing suicide, after realizing how far gone he was after essentially gave his own daughter, Setsuna to Sicks' experiments, leading to her death and swearing Undying Loyalty to him afterwards. Needless to say, it was very cruel indeed
- Dark is Evil: Black hair, dark clothes and a Gothic style to himself and his weaponry is very macabre in shape.
- Dark Messiah: According to his followers, and looks very much like The Antichrist
- Death by Irony:
- Despite being a master Extra-ore-dinary master, he is cut down by metal, Demon World Evil Metal to be exact
- Plus being killed by his own plane which was manipulated by the demonic energy he was so proud of
- Devil in Plain Sight: Though its justified with his Manipulative Bastard powers, its a wonder why people would put faith in him unless they were as twisted as he is.
- Dishing Out Dirt: Able to cause quakes by striking at weak points along the earth's plates
- Duel to the Death: He and Neuro agreed that only one should survive and must settle who's the superior being Neuro comes out on top
- Elemental Powers: He is able to use all of the Five Fingers' abilities in addition to his Extra-ore-dinary main power
- Enfant Terrible:
- Made his first killings by slitting the throats of the other infants in the waiting room, in order to silence the noise they were making. And this is shortly after he was born.
- Killed his mother at the age of 2 by pushing her off a balcony.
- Evil Cannot Comprehend Good: Can't understand why Neuro is adamant about projecting Yako
- Evil Counterpart: To Neuro, both are sadistic manipulators who who care little for others. However, Neuro only toys with people, striving to bring the best out of them by making them "evolve"; while Sicks is monstrously cruel, bringing out the worst from the people around him.
- Evil Feels Good: Basically he wants to wipe out humanity because they don't appreciate evil as much the True Bloodline does.
- Evil Plan: To wipe out the predecessors (mankind) so the descendants of the more advanced race (True Bloodline) can flourish.
- Eviler Than Thou: Establishes himself as the Big Bad by outwitting X's escape plan and foiling Sasazuka's attempts to arrest him.
- Evilutionary Biologist: Believes that humanity is gradually becoming more and more monstrous and therefore must wipe out each other, as it's unnatural that both monsters and humans should live together.
- Evil Versus Oblivion: The Oblivion to Neuro's harvesting Evil.
- Extra-ore-dinary: Metal's history as the main source of weaponry which were smithed by his homicidal ancestors were inherited into Sick's genetic memory leading to his ability to cover his own body in metal to increase his strength.
- Fantastic Racism: Played Up to Eleven, as he plans to wipe out all normal humans to give way to his bloodline. Subverted, in that, it's not out of superiority (mostly) or hatred, but it's it's the natural course of evolution to wipe out competition
- Faux Affably Evil: While he makes polite chat with Neuro, its very obvious he's a complete sociopath.
- For the Evulz: His motivation for anything is that he likes suffering for the heck of it.
- Generation Xerox: Like his "son" X, he prefers to have his actions be as dramatic as possible
- Glass Of Chianti: At one point, when inviting Neuro to lunch.
- Green Thumb: Can manipulate plants, for example causing a tree to come down from the sky in order to prevent Godai, Yako, and Neuro from escaping.
- Half the Man He Used to Be: Neuro's strongest weapon destroys his entire lower body, leaving him with everything above his chest and one arm
- The Heavy:
- Everything aside from the Monster of the Week stories is his fault
- To clarify, Sasazuka's parents were killed by him; he created Sai and Setsuna's degenerating disease was to due to Sicks' experimental drug, which in turn led to Harukawa's Electronic Drug incident
- Hero Killer: To Sasazuka, in a very monstrous way
- Hoist by His Own Petard:
- He is finally killed by his own plane driven by his own Evil Intent
- Sai, now Xi, which he relied on; ends up weakening him enough to be killed by Neuro.
- Humanoid Abomination: Described by Neuro as looking human, but inside being entirely different, being extremely monstrous
- If You're So Evil, Eat This Kitten: He gave two henchmen he was recruiting a test: the first was made to kill his father using his talent of medicine and some of the aftermath includes the victim's eyeballs popping out and the latter was given a cube, made of all the faces he ripped from everyone precious to him, including his family, friends, and co-workers to see if he's evil enough to enjoy the act.
- In the Blood/Lamarck Was Right: How he justifies being so evil: his ancestors' madness and Killing Intent were inherited through generations.
- Kill All Humans: To make way for the superior race.
- Knight of Cerebus: While both X and HAL both got Neuro more serious in battles, Sicks made the series almost Seinen with his pure evilness, and unlike his predecessors, he is utterly without redeeming qualities.
- Lack of Empathy: He cares for no one, as shown when he nonchalantly kills his own minions for little reason.
- Last of His Kind: Played with, Kasai sees that the New Bloodline only exists due to Sicks' charisma and will truly die with his death.
- Laugh with Me!: Sicks forces a victim of his to laugh so he can perfectly disguise himself as the victim.
- Loves the Sound of Screaming: Has people die slowly to savor their agonizing terror of dying.
- Luke, I Am Your Father: He's X's father. Deconstructed darkly as he refers to the latter as a clone of himself, though that's actually the case.
- Made of Evil: Since his ancestors were as sociopathic as he was, he was, he inherited that malice until it made him human in appearance only.
- Manipulative Bastard: His ability to manipulate people may be a combination of Genuine's manipulation through the air and his own evil aura, making them his loyal subjects.
- The Man Behind the Man: Of the series overall especially since he's responsible for the birth of Sai, Sasazuki's family's murder and the death of Setsuna, which led Harukawa to produce the Electronic Drug
- Man of Wealth and Taste: Other than his love of Gothic style, he prepares a proper dinner setting for Neuro.
- Making a Splash: Able to cause flash floods using weak points of water containers
- Meaningful Name:
- A psychopath with twisted desires named Sicks, even to a point where you can become sick from what he does.
- Alternatively, it's Six as in the Number of the Beast
- The Mole: Used the person's own skin after he killed him to infiltrate the Police Department.
- Names to Run Away from Really Fast: Especially since he translates his name into the Number of the Beast
- Nightmare Face: Naturally can produce this when he smiles.
- Nightmare Fuel Station Attendant: Everything about his behavior and acts are horrifying.
- No, Mr. Bond, I Expect You to Dine: His first true encounter with Neuro involves this and forcing people to kill each other.
- Not So Stoic: He is peeved when Neuro manages to beat Genuine and then how he intends to make him a chew toy as well
- Number of the Beast: His calling card which fits with his character
- Offing the Offspring: Does this to Sai after he manages to land a critical blow onto him.
- Omnicidal Maniac: He plans to kill every last human being, except for his own kind.
- Playing with Fire: Sicks was the one who burned Kasai's fire symbol into his forehead, but didn't use it in his Duel to the Death with Neuro
- Rasputinian Death: His death was being cut thoroughly enough to be just be everything above the shoulders plus one arm, then filed with demonic power to paralyze him and finally shredded into pieces by his own plane.
- Sadist: Pretty his motivation other than Fantastic Racism is to have people suffer as much as possible before they die.
- Satanic Archetype: Several hints of this motif is seen with his three skulls (the three headed devil in Dante's Inferno), viewed as a goat headed demon at one point and having an Antichrist feel about him.
- Say My Name: NEEEURROOO!!!
- Self-Made Orphan: Killed his parents at five years old!
- Slasher Smile: At several points, which are all disturbing.
- Sliding Scale of Villain Threat: For one thing, he's the first person for Neuro to take seriously.
- Shape Shifter Guilt Trip: Not himself but he has Sai ,or rather Xi at the time, to turn into Sasazuka's assistant to back stab him and have her turn into members of his his family For the Evulz
- Superior Species: Believes himself as well as the New Bloodline to be this
- Super Power Meltdown: Lost control of his Extra-ore-dinary power after Sai managed to destroy his heart.
- The Social Darwinist: Believes those with great evil intent (namely his "race") should live and posers like the rest of humanity should die.
- The Sociopath: From the literally moment he was aware, he's been killing anyone for the smallest reason.
- Tyke Bomb: Was raised from birth to be the pinnacle of evil, his father even gave him a knife after he was born in order to check if he was evil in the first place
- Ultimate Life Form: According to him, he's the perfection of the evil evolution.
- The Unfettered: He has no restrictions on what he can do to achieve his goals.
- Villain Ball: If he shot Yako after killing Sasazuka, then Sai wouldn't had a Heel Realization and have a The Dog Bites Back pivotal moment that causes his defeat.
- Villainous Breakdown: Started when Sai landed a blow onto him, climaxed when he is reduced to a head and an arm screaming Neuro's name as he killed.
- Villain Respect: Sicks acknowledges Neuro as a Worthy Opponent
- Villain with Good Publicity: Sicks masquerades his twisted experimentations under the guise of a philanthropist.
- Walking Spoiler: Everything takes a drastic shift after he makes his appearance.
- What Is Evil?: His arc is opened up with this question: "Can someone be born as 'pure evil'?"
- Wicked Cultured: He can make theories about evolution, has love of Gothic and killing people in the most horrible way possible
- Worthy Opponent: Views Neuro as this. Neuro agrees, if resentful.
- You Are Number 6: Obviously, his name is pronounced similar to the number six. He also uses "6" as a practical signature; from burning buildings into the number to forcing someone to vomit up a large 6 with their own blood.
- You Have Failed Me: Often with Cold-Blooded Torture.
- Your Favorite: Invites Neuro to meet with him, and tries to arrange a meal for him by forcing several people to kill, right there, by threatening their families and so on. He's wrong in that it's not the mystery itself Neuro eats, but the psychic energy of the motivation behind it, the twistedness that would drive someone to commit murder and try to hide it. Sicks's sick little tableau was the equivalent of offering a starving man Syrup of Ipecac. And then, since they hadn't pleased Neuro, he killed all of them, meaning that they would never be able to produce a real mystery. At that point, the reader learns how Neuro acts when he's really, really angry.
- Animal Motif:
- Dragon or at least he thinks so.
- Neuro on the other hand, thinks its closer to a tick
- Asshole Victim: He is killed by Kasai for failing to kill Neuro, but doesn't earn a lot of sympathy with his passing, considering how he unrepentantly slaughtered thousands of people with his flooding
- The Dragon: Averted, he thinks he's this, but Kasai fits the role much closer
- Faux Affably Evil: He seems to be gentlemanly at first, then some ignorant thugs accuse him of stereotypes
- Hero Killer: To genocidal levels, he actually succeeds in killing nearly three thousand people in the flood he caused
- In the Blood/Genetic Memory: His knowledge about creating flash floods comes from hidden knowledge of his ancestors who first built the Great Wall of China
- Kick the Dog: Shooting at some people who were trying to stop the flood for pure sadism
- Kill All Humans: He offers to have hundreds of thousands of humans to be killed in the following flooding act, he actually succeeds on a large scale, but doesn't reach the number he was estimating
- Making a Splash: Not an actual superpower per se, the collective knowledge of thousands of years of flood building knowledge allows him to cause the greatest amount of damage possible
- Small Name, Big Ego: While he is an extremely competent Hero Killer in his own right, he assumes that he is in fact, The Dragon, when The Dark Chick suits him much better as a role
- Villainous Breakdown: When Neuro uses his sadism tool on him, he cracks epically
- Wrong Genre Savvy: While he is a successful Hero Killer on city size scale, he assumes that not only is he stronger than Neuro because he isn't fighting back, but that he is The Dragon as well. Neuro proves these to wrong with his defeat
- Affably Evil: He's by far the most friendly member of the Five Fingers, but he still hates humans with a passion though you wouldn't know it from how he easily lets people steal from him. However, Yako notes he's much more humane than the others
- Bait the Dog:
- He has no problem with others stealing from him, but is ok with burying them alive .
- He doesn't want to see people suffering not to of guilt, but out of narcissism .
- Berserk Button: If he hurt his face, he'll become enraged
- Beware the Nice Ones/Beware the Silly Ones: Despite his Extreme Doormat tendencies and Narcissist tendencies, he proves to be a much tougher opponent than DR did
- Buried Alive: Tierra's speciality. A notable case is when he took 1,000 people and buried them up to their necks then gagged and blindfolded them. Which is made worse when he plans to crush them with falling debris of the building he destroyed.
- Butt Monkey: He gets things stolen constantly, but makes up for it with his surprising competency
- Crouching Moron, Hidden Badass: Despite being an extreme Narcissist and Extreme Doormat, Kasai even notes that he is a very deadly opponent even for Neuro
- Dishing Out Dirt/Extra-ore-dinary: He can manipulate the metals in his body via X's DNA to have missiles ripping out of his body to shoot his opponents. He pr
- Extreme Doormat: He doesn't seem to mind that things are stolen from him, as long as it isn't his face
- Face Death with Dignity: Subverted, he thinks he does this, but Neuro decides to preserve his head to show off his face in agony
- In the Blood/Genetic Memory: His knowledge of causing quakes and burying alive people comes from hundreds of years of conquerers who did this to their victims
- Not So Harmless: Proves to be quite the deadly enemy once his face was hit, as Neuro found out
- Off with His Head!: Inverted. His head is the only thing remaining after he exploded himself.
- One-Winged Angel: He can be a hulking monstrosity when enraged
- Running Gag: Something is always taken from him
- Weaksauce Weakness: Sharing X's DNA and his metal attributes, his weakness is electricity
- Abusive Parents: His mother was forced to test experimental drugs till her death, which his father, the one who did this to her, decides that she was no better than a lab rat.
- Ambiguously Brown: He's established to be of Indian descent on his mother's side
- Anti-Villain: By far the most sympathetic of the Five Fingers, Type II easily
- Body Horror: He has a parasitic plant implanted inside of him which reduces the impact of bullets, as well as being able twist the veins and skin around his eye to form a spike on his face. Veins pop up on his face and he starts fuming when the plant is active.
- As what he does to his victims, when he releases the capsules he keeps as banglets around his arms, they expel enzymes or bacteria that travel through the bloodstream, corroding and festering the body by changing its chemistry. The skin of the victims who touch the chemicals appear to bubble up and burst, causing an instant but painful death.
- Driven to Suicide: To protect Sicks' secrets
- Evil Former Friend: To Godai
- Eye Scream:
- Does this to his father, and later turns his eye into a spike to stab Godai
- Caused his father's eyes to pop out with the use of drugs
- Freudian Excuse: His father was an apathetic scientist who took his wife's death as something minor, resulting in his desire to kill all the small minded humans
- Green Thumb: An extremely disturbing use of it, he can mix plant chemicals to cause graphic diseases to infect his victims to cause Body Horror-ish effects. He also made a tree into a huge projectile to hit the heroes' vehicles.
- In the Blood/Genetic Memory: His knowledge of plants comes from thousands of years of medicine men who cultivated this art for lethal purposes
- Kick the Son of a Bitch: Kills his father, the same man who drugged his own wife to death, and treated as a minor experiment
- But Not Too Foreign: Half Indian on his mother's side and half Japanese on his father's
- Plant Person: Due to having a parasitic plant inside of him, he's able to manipulate plants as well as his body to make his eye into a spear
- Undying Loyalty: To Sicks enough to kill himself to protect his secrets
- We Used to Be Friends: With Godai
Genuine/ Jennifer Ewing
- Blow You Away: In similar vein to DR, she doesn't actually have wind powers, she claims to become and control the "air" that moves the crowd.
- Butt Monkey: Becomes an even worse one than Tierra as Neuro decides to be even more of a Troll to her than he was
- Brainwashed and Crazy: Neuro decides to brainwash her in order to figure out Sicks' secrets
- Break the Haughty/Humiliation Conga: Her Mooks are defeated, she is rendered unable to fight back and finally she isn't even allowed to reminiscence after her failed Taking You with Me tactic
- Curb-Stomp Battle: Neuro utterly dominates her and her Mooks easily then proceeds to make her his chew toy
- Driven to Suicide: Like Vijiraya in order to protect Sicks' secrets
- Face Death with Dignity: Despite being brainwashed by Neuro, she regains her senses and has her Mook destroy her in order to protect Sicks' secrets
- Flunky Boss: She has Giant Mookss to fight for her.
- Hoist by His Own Petard: Neuro notes that she should've fought herself for two reasons, 1) being on the defensive weakens him greatly and 2) one of her thrown away Mooks helps Yako destroy the bomb implanted in the base
- In the Blood/Genetic Memory: She has inherited the evil intent of Dominatrix witches
- Lady of War: Kasai describes her as being this, as a queen who controls the masses to follow her.
- Non-Action Guy: She has Giant Mooks to fight for her
- Psycho Supporter: To Sicks later Neuro after he brainwashes her
- The Smurfette Principle: The only girl in the Five Fingers
- Smug Snake: Neuro accuses her of being this, hiding from the shadows and being a Flunky Boss rather than fight him herself.
- Undying Loyalty: To Sicks enough to be driven to suicide even after being brainwashed
- Villainous Valor: Even after being brainwashed by Neuro, she decides to kill herself in order to protect Sicks' location
- Witch Species: Genuine's ancestors were real witches and managed to avoid suspicion by winning wars for the community. They eventually gained the peoples' favor and easily dominated over them.
- You Gotta Have Blue Hair: Sports pink hair.
- Awesome by Analysis: While the other Five Fingers have extensive knowledge on elements to help with their powers, his knowledge on fire alone makes him able to create technology to utilize it to its full potential without having to alter his body in anyway to do so, especially not with X's DNA
- Ax-Crazy: Despite being normal for the most part, he revels in the destruction his fires cause
- Badass Normal: Sicks' right hand man and all of his pyrokinetics comes from extensive knowledge on fire rather than supernatural powers and is thus one of the two members of the Five Fingers to have never used X's DNA or any alterations to enhance their power
- Dragon with an Agenda: If only to exploit his evil desires through be allied with Sicks.
- Chekhov's Gunman: He was first mentioned in the HAL arc to be an uncle of a pyromaniac criminal, making his debut in the following arc to prove how Eviler Than Thou he was to his nephew
- Empowered Badass Normal: Subverted, he's the only member of the Five Fingers not to enhance himself and relies only on his pyrokinetics, due to his pride as a human
- Evil Uncle: To a reformed pyromaniac, Homura
- Good Smoking, Evil Smoking: And gives a great quote for this that counts as a He Who Fights Monsters speech which describes Sasazuka's true personality"Y'know, people talk about smoking as it it's a bad thing. As if lonely people or really despicable people are the only ones who light up. But the people who smoke... have another side to 'em. Their true desires are hidden in the smoke they exhale. Strangers don't get this "other side". They only figure it out once they're neck-deep in the good stuff. The people who try to run from their monsters... become driven by those monsters instead."
- In the Blood/Genetic Memory: He has inherited all of the evil intent of those who created fire.
- Irony: While he never manages to kill Sicks he manages to outlive him
- Nice Hat: It covers his burn mark on his forehead
- Only Sane Man: To the True Bloodline's more unstable members, but he' mostly this to Genuine and Tierra; but especially Tierra
- Playing with Fire/Kill It with Fire: He uses a complex series of tubes on his body to create flames and eject them towards his targets, making him essentially a normal man with an extensive knowledge on fire when compared to his allies
- The Starscream: Has made an attempt to kill Sicks at one point and is not as fanatically loyal as the other agents
Takeda KeitarouA member of the police at the start of the series and a dective on the murder of Yako's father along with Sasazuka. Unbeknownst to everyone though, he was the real murderer, and obfuscated the evidence of his involvement. Neuro's involvement, however, put an end to the charade and Sasazuka arrested him.
- Beauty Mark: Has a rather large one on his forehead; his tongue appears to have a similar mark.
- For the Evulz: The reason he killed Yako's father? To see the despair on her face afterwards.
- Knife Nut: With how many knives were left in Yako's father, it's hard to see him as anything but.
- Nice Job Fixing It, Villain!:
- Had he kept Yako and Neuro from investigating the crime scene, Neuro wouldn't have had such an easy time solving the case. It's rather notable because Sasazuka was against Yako investigating the scene, meaning there would be precident to restrict her access.
- That said, it's debatable at how much an impact this would have made, given said crime was solved at Neuro's most powerful state and Neuro hardly follows normal restrictions anyways.
- No Kill Like Overkill: He stabbed Yako's father with so many knives the body better ressembled a pin cushion. Crosses into Cruel and Unusual Death, since it took the victim around fifteen hours to expire from his wounds.
- Old Shame: His involvement in his crime makes the police more lenient towards Yako's investigations into their crime scenes.
- Start of Darkness: Inspires an inversion in Yako. Though he killed her father to see the anguished look on her face, Neuro's involvement turned his crime into the reason Yako persists with Neuro as a detective, and ultimately leads to her bettering herself.
- The Cameo: His involvement in the anime was in the background of one scene, a few mentions, and as a disguise for Sai.
- The Dreaded:
- After Neuro uses some of his trademarked Mind Rape on Takeda, he sees Yako as this.
- Sai disguised as him was enough to make Yako faint on sight.
Washio MasakatsuOriginally an employee of a heavy handed finance company, Washio rose up the ranks by murdering his boss and becoming acting-president. After overconfidently allowing Neuro to make a wager on solving the crime, his office is taken and becomes the main building for the detective agency.
- Animal Motifs: Has many to a bird, calling the office his "nest". His nose and mouth enlargen after the reveal, better ressembling a beak.
- Bitch in Sheep's Clothing
- Jerkass: Murdering his boss aside, Washio once went up against a friend in a class committee election in school. When Washio fell behind, he cripled his friend for a year and won by default.
- Off with His Head!: Through a complicated rig of high-tensile rubber and taunt wire, activated from a distance so as to mark him as innocent.
- The Cameo: Appears a few times more in the manga; once as one of HAL's brain-drug zombies, again in jail, and in a flashback that reveals how Vijiraya met Godai.
- The Cartel: Though it isn't stated what activities he got into aside from general shadiness, Neuro and Yako found packets of "potato starch" in the office after he left. The same packets were later found being supplied by the Hayasaka brothers, and were definitely not starch...
- Why Don't You Just Shoot Him?: One of few villains to attempt to subvert this on Neuro before the verdict was given. He had the unfortunate luck of attempting this when Neuro was at his prime.
The Hayasaka brothers
A pair of brothers who work in the blackmarket. The older is Hisanori and the younger is Yukinori
- Berserk Button: Hurt Yukinori and you will get a rocket from Hisanori. Just ask Kasai.
- Big Brother Worship: Yukinori to his brother, but it's post-Heel–Face Turn that the feelings returned.
- Cuteness Proximity: Hisanori to kittens!
- Even Evil Has Loved Ones: They do love each other.
- Friendly Enemy: Mostly to Yako, not so much with Neuro or Godai.
- Heel–Face Turn: Post Curb-Stomp Battle from Neuro.
- Perpetual Smiler: Hisanori, his Cheshire Cat Grin is actually a Stepford Smile that hides his true intent.
- Pet the Dog: Hisanori to Yukinori and kittens.
- The Cartel: They supply drugs, guns, military hardware, and all kinds of other unsavory things.
HAL IIA corrupted back-up of HAL who managed to revive himself from the computers of the military carrier HAL had stationed himself on. Without Harukawa's goals in mind, he assumed HAL wanted the military weapons to destroy the world. However, before he could get one step towards his plan, Sai finds and downloaded and deleted him, obtaining information on Neuro and the Electronic Drug.
- Small Role, Big Impact: Appears in only one chapter, yet provides data and resources that shapes both Sai and Sicks' plans in dealing with Neuro.
- Villain Decay: His motives, and even the Electronic Drug he carries, are both far weaker than the original HAL's. Justified by being a corrupted back-up, rather than a true revival of HAL.
Kagohara KanaeYako's best friend.
- Only Sane Woman: Aside from her habit to look for a boyfriend who could live up to her (extremely high) standard, she's pretty normal.
Katsuragi HarukaYako's mother.
- Good Parents: Despite not always be there for Yako (being the breadwinner in the family), she's always supportive to her daughter.
- Lethal Chef: Hard to tell if it's played for laughs. Her cooking skills are so horrible that even Yako's iron stomach couldn't take it. She shops at hardware stores for beaters and other kitchen appliances, and at one point she ended up creating radioactive bricks for food, which was later used to line a garden (though they were still radioactive).
Katsuragi SeiichiYako's father, he dies in the beginning of the story.
- The Coroner Doth Protest Too Much:
- Yako's father was killed via his head being cut off with a chainsaw, and his blood was used to paint the walls. Since there was no way to enter the room, it was ruled a suicide by the police.
- Only in the anime. In the manga, his body was pincushioned with knives. And in the manga the police don't think it's suicide, obviously.
- Deceased Parents Are the Best: Yako is very torn about his death, enough to stop her Big Eater habit for a short while.
- Good Parents/Abusive Parents: Zig-zaged between these two tropes since Yako obviously loved him very much (to the point she didn't feel hungry when he died, something she only does when she's in extreme depression), but on occasions, we have flashbacks about his not-so-good-parenting behaviors (like looked down on Yako for not book-smart enough or abandoned his young daughter at the port alone with only some money for tickets just because she's better at fishing than him).
- Posthumous Character: Died in the first chapter.
- Tsundere: Has shade of this but most of the time, she is in Tsun-tsun mode due to all the crazy people around her.
- Bunny-Ears Lawyer: Despite being a huge Stalker with a Crush, he actually is a good furniture seller and craftsman.
- Stalker with a Crush: Seemingly to be this to Yuka (and all women in general).
Mochizuki TateoThe owner of an Underworld Private Research Agency, an Information Company that Neuro now controls through Godai, whom he has designed as vice-president.
- Easily Forgiven: Played with. The only reason he's kept from punishment is so Neuro can have a face for his Information Company.
- Fatbastard: Especially with his Domestic Abuse
- Happily Married: Believe it or not, though it does have its problems
- Jerkass: Towards Godai unintentionally and definitely to his wife
- Man Child: Plays with video games, which he has extreme lack of playing sense.
- May–December Romance: He met his wife when she was still in Highschool.
- Ugly Guy, Hot Wife: His wife is a knock out, while he's a Gonk
- Too Dumb to Live: His main trait. The guy had the deadly habit of finding and growing talents in people but he never thought about actually control them. It usually ends with people turn against him (like the Hayasaka brothers) or gradually take over his business with him being the Puppet King (like Godai). A bit unusual for this trope, he actually benefited from this (after almost lose his life) and now enjoying playing video games all day while making Godai do all the works for him.
- Bunny-Ears Lawyer: A briliant mathematician who loved to build everything with cardoards. Yes, that including multiple-stories house, bride, guns and armors.
- Cloud Cuckoo Lander: He lives a cardboard house that's shaped like a multi-story building as well as guns, furniture and armor.
- Driven to Suicide: An extremely disturbing example involving severe Mood Whiplash.
- Guinea Pig Family: Unintentionally gave Sicks, once he realizes the implications of what such a man can do to his daughter he undergoes severe Sanity Slippage in order to serve him.
- The Mole: He is actually one for Sicks, having given information on Sasazuka leading to the latter's death. Just serving under this man is something he regrets deeply.
- My God, What Have I Done??: Realizes he's sold out his daughter to the incarnation of the devil, something that ultimately causes him to be Driven to Suicide.
- Cloudcuckoolander's Minder: To her father.
- Cynicism Catalyst: Her death was this to Eisuke and her father.
- Ill Girl: Not in the way you'd expect her brain slowly degenerated over time, leading her to be severely unstable and eventually die.
- Meaningful Name: Her name is equivalent to the Japanese pronunciation of the numeral 1/100000000000000000, and was the final password that guarded HAL.
- Mood Whiplash: Her degenerating brain led to her going into random acts of extreme rage at anytime.
- Together in Death: with HAL.
- Walking Spoiler: Being the Freudian Excuse behind HAL's actions and the origins of her unstable mind can be traced to the true Big Bad of the story.
- Creepy Child: Play for laugh at times.
- Horrible Judge of Character: Believe her grandad really loved kids. Maybe she was right, maybe not.
- Man Child: He acts immaturely, but is very competent in his field.
- Butt Monkey: Even at the brink of death, Neuro is able to easily handle her. She is one of the weaker demons n the netherworld
- Body Horror: Her face led to Makai which her kind use as a mean to be able to survive on Earth. If one forcefully tore it wider, it can be big enough for one person to go through. Neuro did that and she ended up complaining that she couldn't find a husband now.
- Even Evil Has Standards: She has no problem attack a helpless, bed-bounded person, but she will not stand to watch a demon at higher caliber like Neuro died on Earth as it is an insult to her.
- Last Episode, New Character: She appears in the second to last chapter, but it still counts.
- Okama: She's this, if the Guyliner didn't clue you.