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Visual Novel / Chaos;Head

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Whose eyes are those eyes?

"If you were God and your delusions became reality.
What kind of delusions would you imagine?
A sensual world? A despotic society?
Destructive sanctions?

Chaos;Head is a Visual Novel and the first entry in the Science Adventure Series. It stars Takumi Nishijou, an Ordinary High-School Student and raging otaku who lives in the Tokyo ward of Shibuya.

Takumi lives in a steel shipping container on the roof of a building, converted into a small apartment. He spends most of his time at home, either playing the fictional MMORPG Empire Sweeper Online (in which he is Neidhardt, the most famous and powerful player ever) or watching anime. He has over one hundred "waifus" (figurines), his favorite being the character Seira from the fictional anime Blood Tune; he frequently affirms his love of 2-D women and his hatred of 3-D women. He is a borderline hikikomori, having crafted a "minimum attendance shift chart" to ensure that he can attend school as little as possible while still graduating.


When the story begins, he is only known to have even semi-regular interactions with a few people: his bratty younger sister Nanami, his ESO guild partner Grim (whom he speaks to online), the school's resident playboy Misumi, and Seira, whom he has become deluded into thinking exists, to the point that he can hear her talking and interact with her as a kind of muse. Beyond these, he seems to be quite afraid of interacting with people, exhibiting classic signs of social phobia (such as extreme discomfort with making eye contact).

This routine life is shattered when, upon coming home one day, he hears the sound of something being pounded into concrete. Looking over, he sees a pink-haired 'demon girl', pinning a body to an alley wall with cross-shaped stakes. The girl turns, smiles, and inexplicably calls him by name, at which point he runs. This scene is the third in a series of bizarre, gruesome murders called the "New Generation" murders. Takumi initially wants nothing to do with this, but a mysterious user known as 'Shogun' begins stalking Takumi, and seems intent on dragging him into the whole mess. Takumi then realizes that this mysterious man is working with the demon girl. Meanwhile, the Noah OrganiZation Of Medical Instruments, or the NOZOMI Group, puppeteers the New Gen incidents for their hidden, sinister purposes. When the bodies continue to pile up, a whole bunch of weird super-powered girls show up and get closer to Takumi, a conspiracy between NOZOMI and several powerful organizations surfaces, and, in the center of it all, Shogun and the Demon Girl make their move, Takumi finds himself forced out of his solitary lifestyle, and into a mystery encapsulating all of Shibuya.


The game has a unique "delusion trigger" system where the player can, at certain points, opt to view one of Takumi's daydreams/delusions. The player is given a choice between a good delusion (happy, humorous, or H in nature) or a bad delusion (paranoid, violent or tragic in nature). For example, when Nanami visits and berates Takumi for not ever calling home, she takes a swig of soda without asking; the good delusion brings up the concept of an Indirect Kiss, prompting Takumi to compare it to a hentai game scene (at which point it almost does turn into one), and the bad delusion involves Nanami taking a swig of coke, then gagging and coughing up blood and dying. Takumi wonders why that happened, then remembers that he poisoned the coke beforehand. Typically these delusions have no direct influence on the story itself (Takumi simply snaps out of it and the scene continues from where it left off), but seeing certain ones triggers flags that can influence which ending you see. Many of these delusions involve blatant reference to anime (or eroge) tropes, as well as surprisingly clever foreshadowing.

The game was made into an anime by Madhouse for the fall 2008 season, with an Xbox 360 updated rerelease titled Chaos;Head NoAH released in February 2009.

A fan translation patch for the game exists, but was taken down from the main site due to an agreement with Nitroplus, which unfortunately led to Development Hell as there's no localized version of the game yet, in fact no news after the "agreement" between the original fan translators and Nitroplus were given.

That being said, a current fan translation by Committee of Zero, a group dedicated to translating Science Adventure content that never came to the west, is currently working on translating the Chaos;Head NoAH version of the game as it is the canon entry that future titles rely on story wise.

In February 2022, the official twitter account for the Science Adventure series posted a tweet hinting towards an official English release, and shortly after dropped a trailer announcing the first ever official Western release of the game to be released in October.

The game is the predecessor to Steins;Gate and Robotics;Notes.

A Sequel, Chaos;Child, was released for the Xbox One in 2014, with different cast of characters in the same setting of Shibuya set several years after the events of Chaos;Head. The anime adaptation started airing in January 2017. An official English version was released on Steam in January 2019.

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Chaos;Head contains examples of:

  • 11th-Hour Superpower: When Takumi recovers from Norose's attempt to destroy his whole entity, he has to come to terms with being a delusional existence. This means that he can treat himself as one, which in turn makes him indestructible.
  • 90% of Your Brain: Norose's reasoning for how the abilities of Gigalomaniacs work.
  • 100% Completion: The achievements track how much of the story you've seen, how many CGs you've unlocked, whether you've seen every delusion, and whether you've made the choice to make Hazuki wear glasses at the beginning of the game.
  • Accidental Pervert: In the NoAH version of the game, Sena accidentally ends up on top of Takumi after he saves her from a building cave in, which results in him getting a hard on due to his natural instincts and because her sweat landed on him, completely not of his own volition.
  • Achievement System: There are a number of achievements in the story, ranging from completing chapters and reaching endings to finding every CG, to doing funny things like getting Hazuki to wear glasses at the start of the game.
  • Action Girl: All of the Gigalomaniac girls, whom are able to summon DI-swords and use them to battle against Nozomi.
  • Adaptation Distillation: It takes around 25 to 30 hours to finish the game (or at least the common route which is the canon events of the story). The anime adaptation, on the other hand, is little short of six hours long. It hardly takes a genius to figure out how much of the story was left out in the adaptation.
  • Affectionate Nickname: Rimi always calls Takumi "Taku." This is to differentiate between him and the real "Takumi", aka Shogun.
  • All Just a Dream: Some of the positive delusions try to provide a Happy Ending by making it so that all the horrifying events were this. Takumi even lampshades the cliche in the first positive delusion of Chapter 7.
    "I couldn’t possibly have anticipated the it-was-all-a-dream twist. But miraculously, there was nothing unpleasant about it. I had a surprisingly easy time accepting it when I heard it had been a dream. And when I thought about it harder, things like DI-swords and making delusions real were simply impossible."
  • All There in the Manual: In the script files for the original game and its NoAH version, there are comments by Naotaka Hayashi himself (the sole scenario writer for Chaos;Head, Steins;Gate and Robotics;Notes) that actually confirm some interesting lore details that were only left up to interpretation in the game proper. This includes tidbits such as the device on Ayase's head during her flashback being one used to scan and obtain CODE samples, and Shogun being the 4th person who was at the Delusion Synchro that occurred at the staking.
  • Aluminum Christmas Trees: The Committee of 300 are actually based off of a real life conspiracy theory.
  • Alternate Character Reading: A minor example is how kanji characters for Takumi's last name, Nishijou, are normally read as Saijou, but in his case it is Nishijou. This is intentional, as his full name, Nishijou Takumi, can translate to "Lightning-fast Neidhardt blossoming the snake." Neidhardt is obvious, blossoming refers to how his DI-sword and personality (as revealed in the NoAH version of the game) is named/represents a Water Lily Stem as he opens up to people (blossoming) and moves forward after resolving himself (the stem). The Snake alludes to the serpent he creates with his delusions to smite and destroy Noah II at the end of the game. Said Snake also represents Takumi repeating the original sin from the story of Adam and Eve, as Adam rejected paradise for the sake of the woman he loved because of the temptations of a Snake, so does Taku in destroying Noah II with the power of a Snake that represents his deepest desires, all for the sake of Rimi.
  • Alternate Timeline: One of the few theories for where the NoAH exclusive character routes take place, considering this version of the game was written concurrently with Steins;Gate.
  • Amplifier Artifact: DI-swords serve as these, acting as a conduit needed for Gigalomaniacs to properly real boot their delusions. Takumi is the only person who has been shown to be able to real-boot without one, which is heavily implied to be because he's channeling the power of the already awakened Gigalomaniac, Shogun.
  • And I Must Scream: During Takumi's final fight with Norose, he's impaled on a stake for 3 days straight and has no way of escape until he dies. All he can do is wait as it slowly eats into him and the pain drives him into insanity, even waking him up the few times he blacks out from the torment.
  • Angsty Surviving Twin: Yua. Her twin sister Mia died in the "Group Dive," the first New Gen incident. Yua then launches her own investigation into Mia's death. She suspects Takumi is involved in the New Gen murders and pretends to befriend him under the ruse of being a girl otaku. When Takumi finds out her true intentions, Yua doesn't take it well.
  • Annoying Younger Sibling: Nanami, who constantly nags and teases Takumi about his Otaku habits and messy home.
  • Another Dimension: Played with. There are times that Takumi believes he's been somehow shifted into a new reality when his memories don't match up with other people, but it's really just Shogun and Rimi using their delusions to rewrite the memories of the people around them to fit a new narrative.
    • The way DI-swords work is they act as a conduit (Sena calls them a pipe) for the Dirac Sea, which is another dimension where antimatter is stored, and through that, antiparticles can be directed into the dead spots of another person, forcing them to see what the Gigalomaniac wants them to see, which can in turn create new things in their reality.
  • Anti-Escapism Aesop: Takumi often tries to avoid interacting with anyone and tries to isolate himself constantly, yet at the same time continues to crave human connection despite what he says and does. He feels like no one ever understands him and that the "3-D world" is crappy and not worth living in, and that immersing himself only in 2-D will make him happy. The horrendous terror and strife he's put through throughout the story continuously reinforce this belief in him. However, the story makes it very clear that trying to avoid his problems will not make them go away, and, ultimately, after finding someone that makes his life worth living, Rimi, he finally steps up and faces his cruel reality head on, taking the fight the Nozomi themselves in order to survive. This culminates in Takumi destroying Noah II with the support of the people he's met in his life wishing for his safe return, even though Noah II is essentially the ultimate form of escapism and would birth a world with no more pain and suffering, which is what he originally wished for.
  • The Anti-Nihilist: Played straight, with all the bitterness and angst included. Takumi eventually becomes this trope by the end, despite being the polar opposite initially as someone who wanted nothing more but to be constantly happy and not face any struggle or strife in his peaceful life. After the living hell of a nightmare he's put through and facing his own despair event horizon upon realizing his life is a lie and that he technically isn't real, he understands all too well how horrible the world really is. But he also comes to realize that with the support of other people who are struggling and traumatized the same way he is, and with someone to live for, he can survive in this world and make something of his life, and be happy despite the sorrow. His life, despite being a delusional one, is still worth living, and he is his own person that can take control of said life, and instill the worth in it.
  • Arc Words:
    • "Whose eyes are those eyes?" ("Sono me, dare no me?") It actually reaches memetic stays in-universe, becoming associated with the New Gen murders.
    • "Don't look at me" is basically Takumi's catchphrase, and represents how he wants to be isolated and considers himself ugly and pathetic.
  • Artistic License – Geography: While nearly every single location in the story is an actual place you can go to in Shibuya, there is one notable exception. The Kurenai Hall building where Takumi's container house resides on doesn't exist in the real world. This is because Shogun real booted the entire building and Takumi's house into existence just to help fabricate the story of Takumi's fake life living out on his own in Shibuya.
  • Artistic License – Physics: Since the whole plot is built on the idea of people who can rewrite the fabric of reality with their minds alone , this kinda goes without saying. While the Dirac Sea containing antimatter and the like is true, people being able to send antiparticles into other people's minds, let alone the conduit for said ability conveniently being a Sword of all things, is completely fictional.
  • Artificial Human: ”Takumi” is a delusion given human form and artificial memories.
  • Band of Brothers: Takumi and his guild partner Grim have this relationship in the MMO they play, always trying to support each other and jokingly teasing each other. Subverted as Grim turns out to be the one behind most of the New Gen killings, and manipulating Takumi. And a woman.
  • Beethoven Was an Alien Spy: Albert Einstein was a Gigalomaniac.
  • Believing Their Own Lies: Sort of played straight. Takumi was implanted with some memories from the life of his other self (his original), and forced to believe he was the original who just decided to live alone in Shibuya, when his creator was actually stuck in a hospital bed for most of the game.
  • BFS: The DI-swords. Humorously deconstructed when Takumi buys a fake one- and laments how utterly stupid he looks having to drag the thing around in full view of everyone.
  • Big Bad: The mysterious old man in a wheelchair, known only as 'Shogun', is the one stalking and haunting Takumi Nishijou, and is using the Demon Girl to perpetrate the New Gen murders gripping Shibuya, all for some hidden purpose. Shogun is eventually revealed as the real Takumi, and his malevolence is all in Takumi's head. Both he and Rimi are innocent, and trying to train Takumi to fight the real villain- Norose Genichi, president of the NOZOMI group who created the super-powered Gigalomaniacs through Mind Rape and used them to power Noah II. He masterminded the murders with the goal of psychologically tormenting Takumi into awakening as a gigalomaniac, then extracting his CODE sample to perfect Noah II and use it to essentially control the world through Mass Hypnosis.
  • Big Damn Heroes: Takumi of all people ends up doing this for most of the cast in the final chapter. First he saves Ayase, Yua, Momose and Nanami from being crushed after a street cave in. Then he saves Sena and Kozue from a delusion attack by Suwa that would've mindbroken them and subsequently defeats Suwa after. And lastly, he manages to save Rimi from the clutches of Norose and destroys Noah II.
  • Bittersweet Ending: The True Ending (called Ending AA in the original game, called Blue Sky in NoAH) is slightly more sweet that bitter. Although the real Takumi is dead, and Sena's father saved Sena at the cost of his own life, delusion Takumi finally realizes and confesses his love for Rimi and so does she, all of the other gigalomaniac girls managed to survive, and the world was saved. That being said, the committee is still out there...
    • Some of the NoAH routes end up being this.
  • Bland-Name Product:
    • Deluoode is the most well known example. There is also We-Key Pedophilianote  for [[Wikipedia.
    • ZigZagged with Coca-cola, as Takumi and everyone else in the game only refer to it as "Cola", but the red bottles on Takumi's desk make it pretty clear it's Coke.
    • There are also Taboo! (Yahoo!), Slavecard (Mastercard), Grouchosoft Mindorz X Perfect (Microsoft Windows XP Premium), three different McDonald's spoofs (McDeinald's, McDynald's and WacTiKald's), Asos (Asus).
    • The forum website that Takumi frequents, @channel is modeled after the Japanese forum website 2ch, or 2-Channel. There is also MewTube (YouTube), and both of these would later resurface (and play major roles) in Steins;Gate.
  • Bookends: The story starts and ends with Takumi lying in the Scramble Crossing of an earthquake ruined Shibuya with Rimi about to murder him.
  • Break the Cutie: Every single heroine and Takumi has gone through this at some point or another, as being mentally traumatized is one of the basic requirements to obtain a DI-sword and become a Gigalomaniac.
  • Broken Bird: Literally every single one of the main 6 girls either is already this at the start of the plot, or becomes this by the very end.
  • Broken Pedestal: Sena towards her father. Her route in NoAH shows that she used to think the world of him even if he wasn't home very often, but the fact his experiments resulted in the deaths of both her baby sister and mother (albeit she doesn't know that was unintentionally), and now she wants revenge on him to avenge her dead family.
  • Call-Back: At the start of the game, Nanami comes in to Takumi's Container House to check up on him, saying "Survival Confirmed!" when she sees he's alive and well. If you choose the positive delusion where she shows up to his house again in Chapter 9, she'll repeat the same words and happy go lucky pose she did at the start of the game, note for note. This is because since she's a delusion, she's swayed by Takumi's positive delusion which reminisces about her doing that for him at the beginning of the story.
  • Call-Forward: In the opening narration of the game, Takumi notes how he wished that everything that had led up to this moment was just another delusion of his, but laments that it's reality. This is because the opening of the game is actually the final scene of the game, where Takumi has been hounded by Nozomi and Shogun and terrified again and again into awakening as a Gigalomaniac, and then was forced to fight for his life several times and be mindraped/tortured horribly before he could destroy Noah II and end his nightmare.
  • Calling Your Attacks: Subverted; in the only instance of the story where this would be applicable, which is in Route B, the character in question can't think of a name to use.
  • The Cameo: While no other Science Adventure characters from later entries appear in this game as this was the first entry of the series, Rimi herself does appear in the Nitroplus Fighting Game PhantomBreaker along with Kurisu.
    • There is a crossover short story called Chaos;Gate where Sena runs into Okabe during the one week gap after Takumi's incident at O-Front.
    • Characters from Chaos;Head do re-appear or are referenced from time to time in later entries, though saying which ones and why would be spoiling later entries.
  • Can't Live With Them, Can't Live Without Them: Takumi's attitude towards "3-D" girls. He claims to despise them and want nothing to do with them, but clearly begins to care for them as the story goes on, and when Nanami and Rimi go missing, he starts breaking down.
  • Can't You Read the Sign?: @chan has a "20 years or older" rule, clearly seen every time Takumi (who is only 17) is reading it.
  • Captain Ersatz: The in-universe fictional character Darth Spider is clearly one of Darth Vader.
  • Cast from Lifespan: Any Gigalomaniac that overuses their powers risks severe damage to themselves. Shogun is very far along in this process, thanks to constant use of his powers along with his genetic disorder, and the creation of Takumi put him in a coma for a year and a half.
  • Catchphrase: Takumi often says "Don't look at me!" whenever he senses God's gaze or when he's in public and people begin to stare at him, due to his lack of self worth and belief that he is ugly and disgusting.
  • Character Blog: Part of the website for Chaos;Head NoAH features blogs by each of the six main girls and one for Takumi.
  • Character-Magnetic Team: Completely subverted, unlike every other SciADV entry. The girls of the cast mostly drift in and out of Takumi's lives because they all have their own agendas and problems to work through, and they don't have much of a reason to stay with him. Likewise, half of the girls don't even ever meet one another as a result, they're not a tightly knit friend group in the slightest or even know one another.
    • The only exceptions to this rule are Rimi and Nanami, who go out of their way to interact with and check up on Takumi often because they care about him.
  • Chekhov's Gun: Gero Froggy seems like an innocuous mascot that is currently a cute hip fad in Shibuya during the story. But in reality, Gero stands for "GE Rate Observer", and the mascots are being used to test how GE Rate affects the groupthink mentality of Shibuya's populace, which is why it mysteriously attracts people to buy it despite not otherwise having a reason to be this popular.
  • Chekhov's Gunman: Several times when Takumi is wandering around Shibuya for one reason or another, you can see a homeless man in a green jacket with disheveled dark blue hair carrying a sign around which talks about how the world is ending. It's revealed later to be Hatano Issei, Sena's father, who once worked with Nozomi and was the one who discovered Ir 2 on Takumi's essay as confirmed in NoAH. Takumi seeks him out in the final chapter in order to find out where Noah II is located so he can destroy it.
  • Chick Magnet: Completely subverted, and the game pokes fun at how with the set up of a blue haired main character who comes into contact with many girls that you would expect this game to be a harem title. But in reality, none of the girls are romantically interested in Takumi in the slightest, and only interact with him for ulterior motives most of the time. The only exception to this rule is Rimi, who ends up falling for him by the end of the story.
  • Chunky Salsa Rule: Subverted. When Takumi learns to heal, he can grow a new head as easily as any other body part.
  • Clap Your Hands If You Believe: When a Gigalomaniac finds their DI-sword, they gain the ability to Real-Boot delusions. This forces others to perceive the delusion through sending antiparticles into the dead spot of their brain, and this shared recognition gives the delusion a physical form.
  • Clones Are People, Too: Shogun considers Takumi to be a real person, just one who was born differently, and he wants Takumi to live on after his imminent death. In ending AA, Rimi finally agrees with Shogun and spares Takumi, despite the latter having become a Death Seeker.
  • Cold-Blooded Torture:
    • A form of Chinese water torture was done to Ayase in her backstory.
    • ''NoAH'' reveals that Rimi was tortured by Norose for years on end with various methods such as waterboarding, starvation, and so on in order to awaken her abilities, to the point where she committed personality suicide many times over in order to cope with the situation.
  • Combat Pragmatist: When push comes to shove, if there's an opportunity to cheat somehow, Takumi will take it.
  • Combination Attack: Gigalomaniacs can work together to Real Boot delusions, resulting in more powerful effects.
  • Conspiracy Thriller: The entirety of the plot is kickstarted by two traitors to the Commitee of 300 funding Norose and the Nozomi corporation to use an equation created by a small child that can allow people to make technology that can bend the fabric of reality, which is fueled by the CODE samples of heavily traumatized teenagers, and they're trying everything they can to awaken one last teen who is one of the most powerful Gigalomaniacs in the world to perfect the device.
  • Continuity Cameo: The name Neidhardt is mentioned in passing in Steins;Gate.
    • The diagrams showing how to control a person's five senses are also used as a blueprint of sorts when Kurisu in Steins;Gate attempts to build a Mental Time Travel machine.
    • Neidhardt's ESO friend Sister Centipede is referenced in Steins;Gate, where she coordinated an attempt by various @channers to locate the IBN5100.
    • Chaos;Head forms the foundation of the overarching Science Adventure storyline, so as such, Robotics;Notes and Chaos;Child have many references and callbacks to this entry in particular as they're more intristically tied to this plotline than Steins;Gate is, too many to list.
  • Cooldown Hug: Rimi delivers one to Takumi when he starts having a breakdown in the middle of a road, having slapped some sense into him just before doing so.
  • Combination Attack: In the ''NoAH'' version, it's revealed that Takumi's snake sword that's made up of antiparticles which he uses to destroy Noah II was formed from all of the 7 Gigalos DI-swords fusing with one another for one giant final strike to end this nightmare.
  • Counter-Attack: In a fight between two Gigalomaniacs, they can turn a delusion against the original user.
    • When Sena and Rimi clash over Takumi's fate, Sena fakes out Rimi by acting like she's going to slash her with her sword, only to return it to a mere delusion so it passes through her as a feint, then real-boots it again to try and kill Takumi. Rimi counters by implanting a delusion of Sena stabbing her father into her mind, and nearly causing her to fall off the roof as a result.
    • When Suwa tries to catch Takumi in a delusion to keep him from defending himself, Takumi turns it around on him, forcing Suwa to kill himself.
    • When Norose uses a delusion that destroys Takumi's sense of himself as a human being, Takumi eventually embraces it, using the delusion to get around No Self-Buffs.
  • Covert Group with Mundane Front: The NOZOMI group seems like a harmless organization of people who manufacture medical instruments, but in reality is masterminding a string of serial killings and have tortured several teenagers into awakening as Gigalomaniacs for their plans.
  • Cruel and Unusual Death: The New Gen murders feature numerous examples of these, such as a guy who was killed by having his blood drained and a guy killed by scooping his brain out with a spoon. However, the 2nd incident easily takes the cake after the circumstances of the murder. Nurse Hazuki, who together with Suwa is the culprit behind all these cases, restrained the unlucky guy on a operating table and proceeded to vivisect him without any sort of anesthesia. And that isn't even the worst part. Remember that an unborn child was inserted into his body-that's Hazuki's baby of whom Suwa is the father. After slicing the victim open, she proceeded to cut her own womb open, rip the fetus out and shove into that guys stomach. And she did this without any anesthesia, all while sprouting an Slasher Smile par excellence and mumbling stuff in some sort of trance.
  • The Cuckoolander Was Right: Ayase generally says very cryptic nonsensical things, such as there being a wicked-hearted king Gladioul who is trying to destroy the world and there being seven black knights needed to stop him. But as the story progresses it becomes apparent that Gladioul is referring to Noah II, and the seven knights are referring to the Gigalomaniacs who were gathered in the city.
  • Cute and Psycho:
    • Kozue is an overall Nice Girl with some disturbing and murderous tendencies, often offering to kill anyone whom she perceives as hurting any of her friends.
    • Hazuki and Suwa, meanwhile, are a Jerkass Serial Killer duo with a veneer of civility.
  • Cute Clumsy Girl: Kozue in a nutshell.
  • Cute Mute: Kozue stays silent in her initial appearances. Then subverted when she starts speaking telepathically to Takumi.

  • Darkest Hour: The Start of Chapter 10. Shibuya is in ruins with thousands of people dead, half of the girls are incapcitated or being incapacitated (Rimi has been captured, Nanami fatally wounded, Kozue and Sena are being mentally targeted, Yua and Ayase get trapped under rubble with Momose). The only one that has a chance of stopping Noah II at this point is Takumi, who's only just awakened as a Gigalomaniac and doesn't have any leads on where to go or what to do.
  • Deconstructed Trope: Takumi often thinks about how wonderful it would be if you could have the power of leveling up with cheat codes and such in the real world, and when he finds out about DI-swords being able to grant you such a thing in reality, he's ecstatic because it means he can escape the paranoia and torment he's been experiencing. But then he discovers in order to obtain a DI-sword, you need to undergo immense psychological strain and mental damage in order to be able to bend reality to your whims, and at that point you might be so broken as a person that you likely won't even be able to enjoy said power anymore. Not such a nice reality after all.
  • Department of Redundancy Department: Serious-mode Yua has a habit of emphasizing sentences by repeating them several times in a row with slightly different phrasings.
  • Despair Event Horizon: After being constantly tormented for the entire game with NOZOMI constantly leading him to believe they'll kill him, forced to follow Shogun's orders to protect a hostage Nanami whose arm was cut off, and then being told that he's actually a fake human that's a clone of another, Takumi tries to kill himself both by either running into moving cars and nearly strangling himself/slitting his wrist (depending on the delusion choice). He then heads to the Shibuya Scramble Crossing to be lynched by the GE Rate riled up crowd.
  • Determinator: After being subjected to stalking, paranoia and many other terrifying events including his sister being kidnapped and held hostage, Takumi awakens as a Gigalomaniac and braves through many battles against the New Gen killers, one of which manages to literally break him and make him lose his sense of self, all to save Rimi and the other girls from Nozomi's clutches. And he succeeds.
  • Deus Sex Machina: Many of Takumi's positive delusions are about one of the girls randomly coming on to him for whatever reason.
  • Diabolus ex Machina: Route B is one huge ever-expanding example of this, featuring among other things, a Despair Event Horizon (Sena) and Body Horror And I Must Scream (Kozue), all of which culminates in a Let Them Die Happy Mercy Kill Just Before the End for a Shoot the Shaggy Dog ending. And the reason why it all happened was that Kozue got knocked unconscious during the earthquake.
  • Didn't Think This Through: You would think after Takumi discovers that Yua was stalking him to investigate if he's the New Gen Culprit and knew that he frequented @Cafe that he would avoid that place from here on out given his heavy paranoia. But instead he goes there once again, and gets caught by Yua who tries to hold him there until the police arrive so they can arrest him.
  • Disappeared Dad: Sena is searching for her missing father, who ran away after the mysterious deaths of her mother and little sister. She eventually finds him, only for him to sacrifice himself to save her from being murdered.
  • The Ditz: Rimi to a T, she doesn't understand Takumi's otaku tendencies, and doesn't take notice of any of the strange events going on around him such as Shogun appearing to him in an empty Scramble Crossing, or how many of the New Gen murders seem to revolve around him. It's revealed to just be an act, and that Rimi has been privy to everything that's been happening to Taku. She's just been trying to prevent it as well as keep his mind off it to prevent him from being awakened.
  • Don't Look at Me!: Actually a catchphrase of Takumi's. Though there are three notable instances of when he uses this phrase. The first two times are near the end (or beginning), the initial one being directed towards a mysterious gaze while the second one is for Rimi. The third one is addressed at pretty much everyone around him after he was set up as an ESP. He rarely says this aloud, it's usually part of his inner monologue.
  • Downer Ending: Endings A and B. In A, Norose is stopped and his machine destroyed, but Takumi chooses to let Rimi kill him so Shogun can live a little longer. In B, Takumi fails to stop Norose or destroy his machine, while he's still killed but from Rimi’s perspective.
    • Most of the NoAH endings are this, usually ending with Taku and one of the girls either dying or being rendered indisposed while Noah II takes over the world.
  • Dreaming of Things to Come: Steins;Gate and the NoAH version of Chaos;Head were written concurrently, and in NoAH it's revealed that Shogun once had a dream of his future self coming to visit him in a Time Machine who told him some things about his future, which really makes you wonder...
  • Driven to Suicide: Takumi tries to kill himself in Chapter 9 after finding out he's a clone and that his life is a lie, multiple times, but fails everytime.
  • Dystopia: What the Committee of 300 wants to make, by enslaving all of humanity under a New World Order where they rule all of the planet, and where humanity is unaware that they are being enslaved, so they won't riot or rebel against it.
  • Dysfunction Junction: It's pretty much a given that the Gigalomaniacs are pretty broken at least, since their powers come from their psychological issues.
  • Earn Your Bad Ending: Ending B. It can only be done on a second playthrough, and unlike either Ending A or Ending AA, it can only be accomplished by making a specific decision or Delusion Trigger at 11 points in the game, and you're never told which ones are which. This results in a recut of Ending A from Rimi's perspective, which is even more heartbreaking than the normal bad ending.
  • Earn Your Happy Ending: Takumi really puts himself through the wringer in order to achieve this, but in the True Ending, he manages to save every girl, and Rimi spares him, while Shogun passes away, leaving his memories/knowledge with Takumi. The girls all survive, and Takumi finally breaks through his isolating mentality and forges a true connection, learning to embrace reality and to stop living in his fantasies.
  • Elephant in the Room: When Rimi comes into Takumi's life, and after he realizes she's not a threat or someone out to kill him, he is constantly reminded of her bloody appearance at the scene of the third New Gen murder, and how everyone seems to suddenly remember her except for him out of nowhere. However, every time he wants to question her about it, his social anxiety, paranoia and fear all overwhelm him and prevent him from being brave enough to confront her about the truth. He instead tries to believe in the shaky idea that she really wasn't at the scene of the murder and that it was just a delusion, as well as the belief that Rimi really is just a friend that he forgot who wants to help him. It's only when it's too late to go back that he's forced to face the truth.
  • Emotionless Girl: Ayase.
    • In NoAH, her route makes it very clear that she's not emotionless, but that she just has a hard time expressing her feelings in a normal way due to her horrific upbringing and warped view of the world around her where she sees people doing horrific things to one another even when they're not happening in reality.
  • Everyone Can See It: Misumi tends to ship Takumi and Rimi a lot due to how much they are around each other and genuinely enjoy one another's company. Nanami used to do this as well for Shogun and Rimi before her memories were erased, and considering that Takumi and Shogun are the same person, it makes sense.
  • Evil Phone: At one point, Takumi gets a phone call from an out-of-service number, where he hears a creepy children's song followed by ambulance sirens and a near-deafening beep. It's later revealed to be the activation sound of Noah II starting up.
  • Evil Only Has to Win Once: The Committee of 300's Project Nozomi is just one of their many plans for world domination that are meant to result in over 5 billion people murdered and the remaining populace of 1 billion subjugated under their rule. Takumi and co. managed to shut down Project Noah before Noah II was activated, but as later entries show, the battle against the Committee of 300 is far from over.
  • Expanded Universe: While Chaos;Head was originally a standalone title, its NoAH version retcons a few scenes and adds a lot of new lore and reveals, which combined with the original story set up the foundation for the entire Science Adventure series. Every mainline entry following this story heavily references the events of Chaos;Head in many different ways, either thematically or in the actual narratives events and how it heavily relies on the science behind Chaos;Head and its conspiracy to be fully understood. These sequel entries follow the plotline of many different groups of people in Japan's Tokyo Ward who are targeted by the Committee of 300 and forced to battle this deadly conspiracy group in order to escape with their lives and thwart their plans of ruling the world. The series is building up a Marvel Cinematic Universe type of storyline where every cast from each entry will come together in order to put a stop to the Committee of 300 and free their world from their tyranny once and for all.
  • Eyes Always Shut: Detective Ban's right eye is almost always closed, giving him a Columbo-esqe appearance.
  • Fanservice: Some of the positive delusions Takumi has qualify for this.
  • Fan Disservice: Some of the negative delusions Takumi has.
  • Fake Band: Phantasm. Their lead singer is FES, also known as Ayase Kishimoto.
  • Fictional Video Game: Empire Sweeper Online, an MMO that Takumi plays.
  • Finger in the Mail: Happens when Nanami gets kidnapped, although instead of a finger, it's a whole hand that gets sent to Takumi.
  • First Girl Wins: As the first girl to appear in the plot, Rimi is the one who ends up getting together with Takumi romantically in the end.
  • First-Name Basis: Takumi is a very rude teenager, who rarely uses honorifics and refers to most of the girls he meets by their first names despite only having just met them. In Japan, you typically only use the first name of people you are close to, and use honorifics along with their last name if you're just acquaintances.
  • First-Person Perspective: In the visual novel. All of the visual novel is first-person; Takumi sees everything the camera shows, including scenes where he doesn’t appear like the Ban and Suwa scenes or the Genichi scenes, though it takes him some time before he realizes this and accesses the knowledge.
  • Flash Forward: The story starts with this, see Bookends mentioned above for more detail.
  • Formulaic Magic: fun10 × int40 = Ir2, sent to Takumi by Shogun in a message, is the equation Takumi discovered in elementary school and the basis of the Noah Project and is referred to as more revolutionary than e = mc2 . What the equation actually signifies is never explained in depth.
  • Foreshadowing: Man oh man, does this story have so much of this.
    • The story begins with Takumi in a destroyed area at night, where a mysterious pink haired girl stabs him with a sword. By the story's end it's revealed that this is Takumi after a massive earthquake, in the remains of the destroyed Shibuya, and Rimi is here to kill him to save what is left of Shogun's lifespan.
    • The start of Chapter 1 begins with Takumi being sent a cartoonish doodle of a person being stabbed by his friend Grimm, and a mysterious user named Shogun sends him an image of a a person being staked to death, paired with the words, "Whose eyes are those eyes?" which are a phrase Takumi uses in his mind. This later ends up being revealed to be Shogun trying to warn Takumi of the staking murder that the New Gen killers want to lure him to as well as to instill some fear in him to help awaken him, and the doodle was Grimm jokingly hinting at said murder as well, which Takumi remembers later on and uses to piece together that Grimm is Nurse Hazuki, one of the New Gen culprits.
    • From the moment Rimi enters the story, there are many signs that she has a very shady and cryptic place of origin, appearing in the flash forward at the start of the game to kill Taku, appearing at the scene of the third murder, Takumi's classmates all remembering Rimi when he doesn't, her playing dumb that the murders seem to be centering around Taku and ignoring all of the warning signs, but Taku tries to turn a blind eye to this to let Rimi help him. In the end it's revealed she was privy to what was going on the whole time, but was trying to keep Takumi out of danger.
    • Much of what Ayase says sounds like cryptic, denpa babble, talking about a Wicked-Hearted King Gladioul who wants to destroy the world and Seven Black Knights that are needed to defeat him. But in reality, she was talking about a prophecy she'd read in The Gladioul Saga which was referring to Noah II and the seven Gigalomaniacs that are currently in Shibuya.
    • Takumi has a memory from when he was 10 years old of one time where he forced to stay home from a field trip and was incredibly mad over this, venting out his anger in violent drawings. The next time, the kids who went on said field trip were injured and the teacher was killed in an accident. This is because Takumi accidentally real booted the events he drew in his drawings to happen in reality.
    • Takumi also has a memory of a Reality TV show where the hosts were getting a precognitive person to predict what was in some boxes without any knowledge of what was in them before hand, and Takumi accurately predicted 100% of the contents. This was because he real booted the contents to be in those boxes.
    • Gero Froggy is a toy mascot that is currently a cute hip fad in Shibuya. One odd thing about this though is that most people seem to gather on Friday in massive droves to purchase them, almost unnaturally so. It turns out that Gero stands for "GE Rate Observer", and the mascots are being used to test how GE Rate affects the groupthink mentality of Shibuya's populace, which is why it mysteriously attracts people to buy it on the same day the GE rate spikes. Ban also puts two and two together to discover that the NOZOMI group is the one backing the company that makes Gero Froggies, which is more evidence that they're behind this conspiracy.
    • It's mentioned a few times that Gigalomaniacs are extremely rare, less than 1% of the population of the planet, yet seven of them are in Shibuya at the same time and all attend the same High School. NoAH reveals that this is because NOZOMI intentionally built the school and gathered them there to keep watch of them for this purpose, though Rimi and Yua being there were not of their own volition.
    • One of the few limitations of Gigalomaniacs is that they can not heal themselves due to their sense of pain preventing them from denying the reality that they are wounded. Takumi is able to get around this limitation because he's undergone so much pain that his nerve endings start becoming numb and he stops feeling it, which combined with embracing the fact that he's a human created by delusions, lets him to delude himself into thinking he isn't hurt and can heal himself.
    • Nearly every time we see a scene where Takumi isn't present, the people present in the scene usually note that they feel like they're being watched by someone. This is because Shogun is watching them through his delusions, which subconsciously passes onto Takumi and gives him the knowledge of those events once he awakens as a Gigalomaniac and recalls those subconscious instances of spying on others thoughts.
    • Two delusion choices when Takumi goes into the hospital talk about how Takumi never left the hospital, that Yua is crazy and should be locked up in one as well and that Takumi is wearing a light green hospital gown. The real Nishijou Takumi never checked out of the hospital and remained there on life support, using his delusions to try and stop Nozomi. Takumi wearing a light green gown hints that he is also Shogun, because Shogun's text color font when he first makes contact with Takumi is light green. NoAH also reveals that Yua is suffering from D.I.D. and is actually Mia, which explains her bipolar behavior.
    • The first positive delusion choice you can choose in the game shows Takumi walking to an alleyway not of his own volition, and hearing an odd sound coming from around the corner, but he is stopped by a pink haired girl who tells him it's too dangerous to go there and calls him Taku. This is likely something that subconsciously came into his thoughts as a result of sharing a mental link with Shogun and his thoughts, as Shogun knows Rimi wants to stop Taku from seeing the crime scene at the alleyway to prevent being awakened and will go to great lengths to protect him, and also knows that Nozomi will drag him there later that day after committing the murder.
    • Yua seems oddly obssessed with finding the New Gen killer, to the point that her entire demeanor changes when it comes up, and she goes to insane lengths to try to achieve this goal. It makes much more sense once it's revealed her sister was an innocent victim of the murders and she believes the killer is heartless.
    • Sena knows more about Gigalomaniacs and what they can and can't do limitation wise, as well as the drawbacks to their powers than anyone else in the cast does. Takumi himself wonders multiple times where she studied this or found out all of this information. When it's revealed that Sena's father was one of the top researchers for Project Noah, and that she was taken to Ark Heart Medical by NOZOMI workers for 3 months after being awakened as a Gigalomaniac to get her CODE sample taken, it's easy to surmise that she read the minds of the scientists who took her in after awakening and found out all of the information from them.

  • G.I.R.L.: Inverted. Takumi's online friend, Grimm, who chats with him about lewd topics like whether swimsuits or glasses look better on girls, is actually an adult female nurse who was trying to shock Takumi into New Gen under the guise of friendly teasing.
  • Geek Physiques: Subverted. Takumi despite spending most of his time locked up in his room, playing video games and drinking Coke, is actually very skinny. However, it is played straight in how he is very out of shape when he struggles to run away from people because he runs out of breath easily.
  • Geek: Takumi, to an unhealthy extreme. He much prefers 2D girls to real women, and would rather not mingle with real people. Yua acts like one to get Takumi to trust her, though it's later revealed that her love for anime and manga is genuine.
  • Get a Hold of Yourself, Man!: Rimi slaps Takumi to get him to come to his senses in Chapter 3, when he's freaking out after witnessing an empty Shibuya and Shogun interrogating him, as well as not trusting Rimi who is trying to get him out of the street before he gets run over.
  • Girl with Psycho Weapon: The entire core female cast is a Dysfunction Junction, and they all come to wield DI-swords.
  • Go Mad from the Revelation: Sena's mother was secretly used as a test subject for creating matter from delusions artificially. Since her second child and Sena's little sister mana died shortly after birth, they created a new baby from artificial delusions and gave it to her. Sena's father was against turning her into a guinea pig, but also didn't want her to realize that her child had died, so he reluctantly approved. The experiment continued for several years, until it was decided that enough results were gathered from it and it will be halted. Sena (who didn't know about the experiment) unfortunately happened to be there when they turned the machines off, causing her mother to freak out upon realizing she's been carrying a corpse and proceeded to tear at her face, eat her child's corpse, and stab her own eyes out with a pair of scissors. All while Sena could do nothing but watch.
  • Government Conspiracy: The Committee of 300. They funded NOZOMI's experiments and heavily supported them them, as well as had a fair few companies and organizations working towards their aims.
  • Gratuitous English: "New Gen", the name given to the bizarre and gruesome string of murders.
    • DI-sword, standing for "Delusion Ideal-sword".
    • Gigalomaniacs fall under this as well.
  • Gratuitous German: "Neidhardt Der Blischnelle", translating to "Lightning-Fast Knighthart" which is Takumi's username for ESO.
  • The Greatest Story Never Told: No one remembers Takumi outting Hazuki as the New Gen culprit in later entries because the footage of it was lost following the Shibuya Earthquake. Though it's possible the Committee of 300 helped obfuscate this fact afterwards to prevent ties to the Church of Divine Light being found.
    • It also goes without saying that no one finds out about Takumi's struggles in future entries aside from the other 6 main girls, because he hasn't told anyone else. As of yet anyways...
  • Guide Dang It!: While the NoAH routes are pretty simple to get (you just have to check the delusion trigger choices that appear when a girl first shows up in the story and then answer some obvious questions), good luck getting Route B without a guide. You won't know that you need to pick choices that mention "Whose eyes are those eyes" in order to obtain this route.
  • Handsome Lech: Takumi's best and Only Friend Misumi is always bragging about the many girls he gets with, and shows interest in nearly all the girls Takumi encounters.
  • Harmful to Minors: Sena and her sister were essentially used as guinea pigs in the experiments done by NOZOMI.
  • He Knows Too Much: Suwa, one of the New Gen killers and Ban's partner, kills him in cold blood because Ban uncovered too much of the truth behind the NOZOMI conspiracy.
  • Healing Factor: Subverted. Gigalomaniacs can alter reality, but they can't use their powers to heal. This is why Shogun cannot heal himself and is doomed to die. Eventually, Takumi learns how to bypass this restriction which is instrumental in allowing him to destroy Noah II.
  • Heroic BSoD: Takumi has two during the course of the story. The first is after chapter 6, when he is tricked into believing his sister is dead. The second is after the revelation that he's an Artificial Human.
  • Heroic Sacrifice: Hatano Issei willingly takes a bullet for his daughter, Sena, after Suwa tries to kill the both of them. He succumbs to his wounds after.
  • Hope Spot: Takumi believes that Yua doesn't have any ulterior motive for talking to him and that she genuinely came into his life because she liked him and wants to help him. Sadly, this only ends up being partially true.
    • Takumi later believes that Rimi doesn't have an ulterior motive in helping him and he ignores the warning signs that she's suspicious because he wants to be helped since he's being targeted by the New Gen killers. It doesn't last.
  • Hospital Hottie: Shino. Also a Meganekko, to an extent.
  • Hourglass Plot: Rimi spends most of the game trying to save Takumi from the Nozomi's machinations (the New Gen incidents) and keep him uninvolved in them so he won't become traumatized or killed, and she even saves him from being murdered at the hands of Sena at one point. By the end, Rimi is kidnapped and Takumi ends up being the one who has to return the favor and saves her from Nozomi's clutches.
  • How We Got Here: The story starts with Takumi lying in a ruined Tokyo street. A Girl summons a Sword out of thin air and kisses him just before she stabs him. The context is that he has just defeated Norose and was blasted outside by the force of his machine, which caused an earthquake that destroyed Shibuya. He begs Rimi to kill him so the real Takumi, Shogun, can live a little longer while he dies as a mere clone. Subverted in the AA ending, which reveals what actually happened is her sword wasn't Real Booted, because Rimi decided to save Takumi instead.
  • I Didn't Tell You Because You'd Be Unhappy: There is no good way to tell your friend that you've developed feelings for that their entire existence is a lie, and that they have fabricated memories and no home or true family. This is the reason Rimi doesn't tell Takumi the truth until he returns to what he believes is his home only to find that it doesn't exist.
  • The Illuminati: The Committee of 300 who have control of most of the influential corporations world wide and have incognito spies everywhere. The goal of Nozomi is to create a device that will allow them to defeat the Committee so they no longer have control of the world.
  • Image Song: Each heroine has her own Image Song that plays during the credits of her respective route in the Xbox 360 version.
  • Imaginary Friend: Seira, from Blood Tune, is this to Takumi. She is also not the best one, as she frequently encourages his unhealthy habits and retreating from reality, then insults him whenever he does begin to connect with the outside world.
  • Imagine Spot: Defines Takumi's 'delusions', but it seems as though he doesn't remember them. Some might go into Daydream Surprise territory, except they're obvious to the audience, particularly because you have to trigger them yourself in the game.
  • In-Series Nickname: Given to a few characters of the cast:
    • Takumi: Neidhardt, Takumi-shan, Taku
    • Rimi: The Demon Girl, Sakihata-shan
    • Ayase: FES
    • Hazuki: Grimm
    • Suwa: Darth Spider
    • The real Nishijou Takumi: Shogun
  • Insane Equals Violent: While this isn't seen often in the original game, NoAH has several instances where Kozue completely loses her temper and kills/maims numerous people when her trauma with mirrors is triggered.
  • Internet Jerk: Takumi is a memer who can be pretty mean and arrogant on the internet, when in reality he's a passive, paranoid and quiet teen with social anxiety who rarely can get a word in edgewise in conversations.
  • Interrupted Suicide: Ayase. Takumi's first conscious use of his delusionary abilities in the game is to create a flowerbed which breaks her fall after she attempts suicide by jumping off the roof of the school. And later on, Takumi himself gets interrupted multiple times when he tries to off himself, once by an illusion of his sister, then by Shogun, and then Rimi herself decides not to kill him like he requested.
  • It Sucks to Be the Chosen One: Takumi was chosen (or rather, created) by Shogun for the sole purpose of suffering enough to awaken as a Gigalomaniac, then destroy Noah II which is a near impossible feat. His creator did give him free will so he could live a peaceful life after achieving this goal, so it's not entirely bad at least.
  • It's a Small Net After All: Averted- Takumi encounters random comments, spam e-mail, and useless search results in the process of finding whatever he is looking for at the time.
  • It's All My Fault: Takumi experiences this when he fails to save Nanami at O-Front, blaming himself for what he believes to be her murder. Somewhat lessened later when he finds out she survived, but she still lost her hand in the process and he blames himself for that regardless.
    • Shogun blames himself for the entire crisis the Gigalomaniacs face in the present, because he created Ir2 which was manipulated by offshoot traitors of the Committee of 300 for their personal gain, which led to every Gigalomaniac involved to be tracked down and tortured for this plan.
    • Hatano Issei entirely blames himself for the deaths of his wife and daughter as well as Sena being traumatized for life because he willingly let his wife and daughter be used in a NOZOMI experiment.
  • Leaning on the Fourth Wall: Takumi often remarks on how he feels the "Gaze of God" watching him, and so do most of the other characters in the story whenever we see scenes of them where Takumi isn't present (poking fun at it being the player of the game).
    • Takumi mentions at some points that he thinks he's in a game world due to how ridiculous the events that happen to him and the people he meets are, as well as this insane conspiracy he's trapped in. He even says that he wants the person watching him from the screen beyond to reset his level and make him a stronger, more manly character.
    • Whenever Takumi bonds with Rimi or Yua and they seem to be romantically interested in him, he mentions "IT'S A ROMANCE FLAG!" in his thoughts.
    • In the anime version, after the common eye phrase pops up, he looks directly towards the camera, as though he noticed the viewers watching him for no given explanation. This seemingly confirms that the eyes he's always referring to are the eyes of the viewer.
  • Lethal Chef: Subverted. In one of the NoAH routes, Nanami makes some eggs and sandwiches for Takumi and he says it tastes pretty great.
  • Lighter and Softer: Chaos;Head Love Chu Chu, a true Unwanted Harem romantic comedy version that's actually a sequel to the main series of events of this entry, but is free of the blood, gore, and overall horror that the original is known for. It serves as an epilogue that details what the cast is going to do with their lives after surviving the nightmare that was the original game.
  • Limited Wardrobe: Justified. All of the main girls are Suimei Academy students, and the story takes place in the middle of the school year, so they're required to have their student outfits on most of the time as a result of Japan Cultural norms. Rimi actually has a casual outfit she wears in scenes prior to pretending to be one of Takumi's classmates.
  • Little Sister Heroine: Nanami. The way the game works means that as with the other female main characters, you can trigger certain 'delusion' events about her that occur only in Takumi's head, but that he doesn't control. Several 'delusion' events play up this angle, such as with the indirect kiss scene. Of course, she is technically not his real sister, as he is a clone of the real Takumi, Shogun.
  • Locked Out of the Loop: Nanami has no idea that Takumi is being targeted for New Gen and just casually interacts with him thinking nothing is wrong. Even when she gets kidnapped by Nozomi and tortured she still has no idea what's going on, and only wishes for her brother to remain safe after she's rescued.
  • Loners Will Stay Alone: Takumi is practically the stereotype for this, complete with an obsession for online gaming, and imaginary wives. He is forced out of it, in circumstances he really does not enjoy at all.
  • Loophole Abuse: The finale. Takumi figures out how to bypass the No Self-Buffs limitations on Gigalomaniac powers, and is able to infinitely regenerate, allowing him to destroy Noah II and Norose, and save the world.
  • Lotus-Eater Machine: Noah II is exactly this, as its purpose is to create something of a delusion synchro among all of humanity that erases from sight any and all bad occurrances in the world, so everyone can live in an eternal utopia where nothing ever goes wrong, and achieve permanent peace.
    • At the end of route B, Takumi imagines himself in a harem with the heroines. Takumi didn't escape it.
  • Love Confession: Takumi realizes he has feelings for Rimi at the climax of chapter 9, but doesn't tell her because he knows he will die soon, and he didn't want to hurt her. This is exactly how things end for him in A Ending, though Rimi kisses him as she stabs him to ease his pain.
    • In the True Ending, Blue Sky, following their kiss, Takumi survives because Rimi spares him by not real booting her sword, saying that she loves him and wants to spend her life with him. Takumi reciprocates, finally confessing that he loves her too, and the two cling to each other in the rain. They then use their delusions to clear the cloudy sky, so they can finally see the blue sky they've been fighting for all this time.
  • Love Makes You Crazy: Yua cares so much about her sister that she goes to insane lengths to find the killer and bring them to justice to avenge her. This includes stalking Takumi for information, trying to build trust with him to get more info out of him, and building an entire case against him claiming that he has a split personality that is committing the murders.

  • Madness Mantra: Takumi is prone to doing this a lot. His favorite phrase to chant when he's terrified out of his mind is "I don't wanna die. I don't wanna die. I don't wanna die...".
    • Takumi's worst case of this is in Chapter 9, once he discovers his existence is a lie and that he is just a clone of someone else.
      Takumi: Kill me... Kill me... Kill me... Kill me... Kill me... Kill me... Kill me... Kill me... Kill me... Kill me... Kill me... Kill me... Kill me... Kill me... Kill me... Kill me... Kill me... Kill me... Kill me... Kill me... Kill me... Kill me...
  • The Man Behind the Man: While NOZOMI are the main threat of this game, the group where they came from, the Committee of 300 is not present in this story, and if anything, Takumi stopping NOZOMI's ambitions helps the Committee more than anything else.
  • Manic Pixie Dream Girl: Takumi hopes that Yua will become this to him, helping him get out of his shell.
  • Meaningful Name:
    • The kanji for the name "Takumi" has the same character used for the word "Snake" in it. Takumi's sword becomes a snake when he summons antiparticles in his sword to destroy Noah II. This is also a christian allusion, as Takumi is rejecting eternal paradise in Noah II like how the snake in the story of Adam and Eve led the titular duo astray into committing the original sin that caused them to reject paradise.
    • The name 'NOZOMI' is Japanese for 'Wish', which refers to them being able to grant the wishes of everyone in the world via Noah II's delusions to give everyone a happy life and prevent any further war.
  • Mega-Corp: Noah OrganiZation Of Medical Instruments, or NOZOMI, owns several other companies, notably the one that sells the Gero-froggy/Hoppy the frog figures, and is the main enemy faction that leads a conspiracy surrounding the New Gen murders.
  • Messianic Archetype: Takumi is praised as a messiah after he uses his Gigalo powers to out Hazuki as the New Gen culprit (which in the eyes of the publc, appeared to be a "miracle" as he literally broadcasted her memories onto the electronic screens in the Shibuya Scramble Crossing), and people begin worshipping him. Though this is shortlived as he soon calls them out on their hypocrisy for making him a pariah not long prior to this. Takumi does end up being the one to save the world and humanity from Noah II though, and nearly dies to achieve this goal in the process. For bonus points, his creator was a Godlike near omnipotent being who created him to suffer and save the world, and who he is also one in the same as in body and mind, much like Jesus and God in the holy trinity. Takumi was also born of a "virgin" and through unconventional means, much like Jesus as well.
    • Lastly, Takumi suffered for 3 days straight in a delusion (through Norose's impalement torture), and also dies at the end of said delusion, but after that delusion, he essentially becomes an invincible god through his power and saves the world, and then reaches "heaven" (reaching the blue sky with Rimi). This mirrors how Jesus was crucified for 3 days straight and died, then ascending into heaven and reuniting with the holy trinity, becoming God once more.
  • Memetic Mutation: Applied in-universe. After the discovery of the fourth New Gen murder, which had "Whose eyes are those eyes?" written in blood, it becomes publically known to the entire populace of Shibuya. It soon spreads to message boards, forums, t-shirts, and even as a Verbal Tic in everyday conversation. This is Played for Drama, as the player is firmly reminded how disgusting it is that these people are effectively making a spectacle of a real tragedy with real victims.
    • It's later revealed that the reason Shibuya's population are making essentially a show of the New Gen killings is because of the GE Rate's spikes caused by Noah II influencing their Biorhythms to heights that cause their emotions to be thrown out of wack.
  • A Million Is a Statistic: Takumi invokes this when he says he doesn't give a damn about saving the world from NOZOMI, and only cares about destroying Noah II to rescue Rimi.
  • Mind Rape: Most of the delusions that Noah II causes are psychological attacks, so this is to be expected.
  • Mind Screw:
    • With Takumi leading the narrative, not only does he not have any idea what's going on, the audience doesn't know much more than he does.
    • This happens from a gameplay perspective as well. Choosing a delusion trigger will show a flash of images, followed by the screen going slightly blurry, as a sign of Takumi having a delusion. As the game progresses, these indications won't always show up when a delusion is in progress; the player will know only after the game cuts them off in the usual manner. To make things even more confusing, delusion triggers sometimes trigger real events to happen to Takumi.
  • Minimalism: Despite having a decent sized OST, the game doesn't make much use of it for the sake of atmosphere, you'll mostly hear Takumi's PC fan more often than not as he spends most of his time in his room, frightened and hoping nothing bad happens to him or comes for him, giving the game a very eerie, scary atmosphere.
  • Multiple Endings: Three ones in the main game (Ending A is the Common Route Ending, Ending B is a bad ending, Ending AA is the True Ending). There are 6 added routes and endings in the ''NoAH'' version of the game, each one tied to one of the main girls of the cast, and all must be completed along with the Common Route and Route B in order to obtain the True Ending in that version.
  • Nerds Are Sexy: Despite wearing glasses, having very good grades and being a big anime and manga fan, Takumi thinks that Yua is pretty beautiful. That being said, Takumi himself is also a nerd, so this is probably more appealing to him than anything.
  • Nerds Are Virgins: As expected given his personality, Takumi is a virgin. But given that he gets together with Rimi at the end of the game, that might not be forever...
  • N.G.O. Superpower: The Committee of 300 in a nutshell, which is pretty easy to see when NOZOMI, an offshoot group of them, managed to concoct a world changing conspiracy under the noses of the mass public, and had the funds and science neccessary to achieve this without batting an eye.
  • Nothing Is Scarier: In Chapter 3, Takumi finds himself in a Shibuya where there is no one around but him, and he runs around half of the city trying to find any sign of life, but nothing remains. Despite his aversion to interacting with people and wanting to be alone most of the time, even he caves into this fear of being the only one left in the world. This was the result of Shogun showing Takumi a delusion to frighten him and also talk with him.
  • No Self-Buffs: Gigalomaniacs can't heal injuries with their powers. This is because their powers don't allow them to ignore the pain their body is telling them they're experiencing. This is subverted when Takumi creatively figures out to circumvent this by using a delusion to null his sense of pain, as well as remaking his body to be one similar to an Amoeba that can take any shape so he can easily regenerate.
  • Official Couple: Rimi is the main heroine, and the story revolves around her relationship with Takumi, both romantically and otherwise.
  • Oh, Crap!: Takumi when he inadvertently tells Yua where he lives after she's been stalking him for most of the early game.
    • Also Takumi in Chapter 4 when he realizes the police were tailing him all over the city and he makes a run for it to try and lose them.
  • The Omniscient Council of Vagueness: Norose and the two traitors from the Committee of 300 talk about the GE rate and Noah II tests in a Nozomi Building office and how they need to awaken more Gigalomaniacs for their plans.
  • Once More, with Clarity!: The entirety of the first scene in the game makes complete sense once you see it again at the final scene of the story, Takumi is rendered immobile due to his battle with Norose, Rimi stabs him to save Shogun's life, and Shibuya is in ruins because of the earthquake caused by Noah II.
  • Otaku: Takumi in a nutshell. Specifically of the Anime sort, though he really likes his MMORPG. He's a frequent @channeler who gets all the memes, can recognize many seiyuu just by hearing their voices, and keeps up with all of the recent animes airing at the current point in time.
  • Police Are Useless: Subverted. Ban actually manages to uncover most of the Conspiracy with help from Momose and Yua. However, this is rendered null when Suwa kills him for learning too much.
    • Also justified, as even if the police genuinely tried to protect Takumi, Nozomi's porters would mind control them and stop them from being able to help him.
  • Poor Communication Kills: Takumi never confronts Rimi over her shady appearance at the murder scene and in his life, and he keeps trying to run and ignore the signs that he's being targeted for New Gen, refusing to face it. By the time he finally accepts the call, his sister has been kidnapped and tortured, Rimi has also been kidnapped, and the entire city is destroyed by a Noah II powered earthquake.
  • Powered by a Forsaken Child: What makes Noah II properly function are the CODE samples taken from Gigalomaniacs. But in order to create Gigalomaniacs to take said CODE samples from, you have to subject them to severe psychological trauma to the point that they mentally break in order to alter their brain patterns. All of the Gigalomaniac CODE samples used to power Noah II are from teenage girls.
    • By extension, in order for a Gigalo to obtain a DI-sword that will allow them to bend reality requires them to undergo severe psychological trauma.
  • The Power of Friendship/The Power of Love: Takumi sees his fellow six Gigalomaniacs praying for his success and safe return while undergoing a delusion attack, which helps motivate him to turn it around.
  • Product Placement:
    • Takumi only drinks Coke.
    • Actual Doujinshi store chains like Mandarake are mentioned in game, along with bootleg brands of Google and Youtube.
  • Pyrrhic Victory: A Ending, where Takumi destroys Noah II, but the town is destroyed and he dies in the process as well.
  • Psychic Link:
    • Kozue uses this to communicate telepathically. It's stated that somehow it is entirely different because it runs off the power of delusions.
    • Takumi and Shogun have one as well and subconsciously share memories and thoughts from time to time, mainly because they technically are the same person (the former being a delusion clone of the latter).
  • Psychological Thriller: This story's genre in a nutshell, which makes sense as one of the main goals of the villains is to shock Takumi into awakening as a Gigalomaniac so they can obtain his CODE sample and perfect Noah II.
  • Rapid Aging:
    • Overusing the power of delusions apparently causes one to age faster. This is only relevant to Shogun though, as he real-booted a literal world shattering equation into existence at the age of 10, which ended up causing him to age faster. As a result, he's practically at death's doorstep at the age of 17 once the story begins.
    • According to the sequel, Chaos;Child, it's heavily implied that this is the same illness that afflicts the Hekiho Academy students, and that the rapid aging is a symptom of the disease being cancer, which is destroying the telomeres of the people afflicted, and telomeres affect the aging cycle.
  • Redemption Equals Death: Hatano Issei sacrifices himself to save Sena from death at the hands of Suwa, redeeming himself for getting his wife and baby daughter caught up in a Nozomi experiment that cost them their lives.
    • Shogun kickstarted the entire plot when he inadvertently created an equation that can warp the reality of the world, which Nozomi then got a hold of and used to create Noah II. As a result, he constantly uses his delusions to put a stop to Nozomi's plans despite how it deteriorates his body in order to atone for this, ultimate succumbing to his wounds at the end of the story after the world has been saved.
  • Rescue Romance: Takumi braves through many battles against the New Gen killers and Norose himself, as well as a crap ton of psychological trauma and mental breaks in order to save Rimi. After saving her, Rimi spares him and confesses that she loves him, to which he responds in kind, and the two begin to date afterwards, trying to rebuild their lives following their traumatic pasts.
  • Revenge Before Reason: Sena flat out admits in her character route that she knows that stopping Noah II and NOZOMI is a very important thing she should do, but prioritizes killing her father before she moves to do that because it matters more to her. This results in the town being destroyed by the quake and Takumi having to pick up her slack and destroy Noah II himself instead.

  • Samus Is a Girl: Grimm, Takumi's best friend on the internet, is actually Female Nurse Hazuki Shino, one of the New Gen killers.
  • Science Fantasy: While on the surface it seems like this entry leans on the realm of Fantasy what with people who can literally warp and bend reality to their will, and are wielding "magical" swords, there's actually a lot of science behind them. The DI-swords are just conduits that allow certain people to channel antiparticles from the Dirac Sea into their primary dimension order to real-boot their delusions, including real-booting the swords themselves. People that can do this have different brainwaves from others, and there are some limitations on what they can do, such as being unable to heal themselves due to the pain they feel in their bodies. Overuse of their powers also causes many antiparticles to stock up in their DI-swords, which can erode the bodies/minds of the users and cripple them or even kill them.
  • Serial Killings, Specific Target: Played with, as the ultimate target of the New Gen murders, the victims of which number in the double digits, is not someone the culprits aim to kill specifically- rather, they seek to use the killings to psychologically torture Takumi Nishijou into awakening his Gigalomaniac powers, and then extract his CODE sample (brainwave pattern), to power Noah II and Take Over the World.
  • Serious Business: Do NOT mess with Sena's popsicle.
  • Shared Mass Hallucination: One of the central ideas, but it runs on the idea in reverse: if you can get more than one person to see the same thing (real or not), it becomes real. Whether it's explained as magic or science depends on the character given the explanation, although the story focuses more on the scientific one.
  • Shipper on Deck: Misumi ships Takumi and Rimi here and there after seeing how much time they spend together.
  • Shout-Out:
    • There is a lot of talk about a sci-fi movie series called Spark Wars, in which the villain is a person in black mask called Darth Spider.
    • Many of the figurines on Takumi’s shelves are from real world, such as various Type Moon characters like Arceuid, Saber, and Rider.
    • Takumi makes a few Jojos Bizarre Adventure references, like often quoting "But I refuse!". In Sena's route, when he's going up a large flight of stairs that seem to never end, he says he's reminded of Polnareff.
    • Takumi and Rimi make a Gundam reference in one of the chapter 4 delusions, where they both say and complete the phrase, "You don't want to acknowledge it. That your youth led to your mistakes."
  • Show Within a Show: Blood Tune. All the audience really knows about it is lead character Seira, who Takumi is deluded enough to see talking to him.
  • Shrinking Violet: Takumi and Kozue, both of whom find it very difficult to talk in reality and stay quiet most of the time. Kozue talks to her close friends using telepathy thanks to her Gigalo powers.
  • Slasher Smile: Characters sport them frequently in Takumi's bad delusions. Norose starts sporting these frequently as well after he's revealed to be the Big Bad.
  • Split Personality: Takumi starts to think he had one that was responsible for the New Gen killings. Yua in particular thinks that Shogun is this. He was completely wrong- he is actually a clone of Shogun, and the killings were done by someone else.
  • Spoiler Opening: The gradual reveal of the different Gigalomaniacs throughout the story isn't quite as exciting after you see all of them except for Takumi and Norose themselves, holding their DI-Swords in the opening.
  • The Stinger:
    • Chapter 1 ends with Yua revealing that Takumi was orchestrating a conversation to himself under both the names of Neidhardt and Shogun, implying he has a split personality.
    • Chapter 2 ends with the phrase that only Takumi knows and has said in his phrase appearing at the 4th murder, implying that the incidents are targeting him specifically.
    • Chapter 7 ends with Nanami reappearing at the school after her kidnapping, but Takumi sees she has a wrapping around her wrist, implying her hand might have been cut off after all.
    • Chapter 8 ends with Takumi going back to his home, only to find that he has none at all, and for Rimi to confirm that he has no home. We then see Shogun returning to his hospital room, only to find that the name of the room belongs to Nishijou Takumi.
  • Stupid Evil: If Norose would just accept that Nishijou Takumi isn't worth awakening as a Gigalomaniac even if it means perfecting Noah II, they would've won and ruled the world before the story even began.
  • Title Drop: Averted, though it's clear that the title refers to Takumi's chaotic state of mind, filled with paranoia and delusions that get increasingly worse as the game progresses.
  • Superpower Disability: A Gigalomaniac can become this if they abuse their powers so extensively that too many antiparticles stock up in their DI-sword and begin to erode away their body and mind, essentially crippling them and potentially killing them. This is what happens to Shogun, who is forced to ride around in a wheelchair due to how heavily his body was damaged by his extensive use of delusions and the real booting of Ir 2.
  • Sword of Plot Advancement: After Ayase/FES gives Takumi a cryptic offhand comment about DI-swords, he starts searching for it, if only to gain some security in his current situation, wherein someone may or may not want him dead.
    • In a more literal sense, all of NOZOMI and Shogun want Takumi to awaken as a Gigalomaniac and in turn get his sword for different reasons, so he literally needs the sword in order to progress to the endgame of both their plans, which he eventually obtains.
  • Taking the Bullet: Sena's father, Hatano to protect Sena from getting shot by Suwa.
  • Technobabble: Most of Takumi's encounters with Sena result in her explaining something about Gigalomaniacs in this manner. Takumi doesn’t understand it at first, and labels her a Conspiracy Theorist spouting off tinfoil-hat theories.
  • Techno Babble: Anytime Sena explains information about the Gigalomaniacs and why they work the way they do.
  • Theme Twin Naming: Yua and Mia.
  • This Is Reality: Referenced rather frequently, but most often by Takumi himself whenever he snaps out of his delusions.
  • This Is Unforgivable!: Rimi towards Norose, who tortured her for a year and kidnapped and tortured Nanami.
    • Sena towards Hatano Issei, her father, literally seething with rage anytime she thinks of him and obsessing over the day she can kill him to avenge her dead family.
  • Third-Person Person: Kozue, referring to herself as Kozu-pii.
  • Theme Song Power Up: Once Takumi sees the prayers of the girls who wish for his safety, and finally accepts that he is loved and his existence is one worth living, the original game opening called Find The Blue plays. Following this, Takumi manages to break out of Norose's delusion attack and real boots a delusion that he's dulled his sense of pain and can regenerate himself, allowing him to finally turn the tables and defeat Norose, saving the world.
  • Tomato in the Mirror: Takumi is actually a delusion of...himself. The other him being what the protagonist Taku knows as "Shogun".
  • Tone Shift: Darth Spider. When he shows up, an already dark story takes a turn for the deadlier.
  • Took a Level in Badass: Takumi does this at the end of the game. After being tormented and antagonized for the entire game, Takumi finally has had enough, finds something worth fighting for (Rimi), grits his teeth and launches an assault against NOZOMI themselves, outting Hazuki as the culprit, killing Suwa by reversing a delusion on him, and finally after a long an arduous battle of minds, defeats Norose and destroys Noah II. Not bad at all for an easily frightened Otaku.
  • Trademark Favorite Food:
    • Sena loves Crunchy-Kun popsicles.
    • There's also Momose and her pronounced fondness for Japanese sweets.
  • Tsundere:
    • Sena. She even has a Shout-Out to Shana.
    • Nanami crosses this with Annoying Younger Sibling and Little Sister Heroine. She often mocks her brother for being a sloppy recluse, but shows herself to truly love him when she gets captured- she calls his name and wants to see him again.
    • In one of his positive delusions, Takumi gets a call on his phone from an (unnamed and otherwise nonexistent) incredibly generic Tsundere love interest, whose every second sentence is "It's not that I like you or anything".
    • I Love Tsundere Music Player (Extras) - "I'll let you listen! But only because it's you."
  • Trauma Conga Line: Basically all of the cast experiences this at one point or another due to their statuses as awakened Gigalomaniacs. It's practically unavoidable.
  • Troll: Takumi loves to be this on the internet. One time he even kills an entire party of players that was dragging him down and steals their items.
  • Troubling Unchildlike Behavior: Kozue often talks casually about killing people who bother her and anyoen she cares about, and is very sadistic towards the ones who try to hurt her, as shown in NoAH.
  • True Companions: Rimi and Takumi becomes this to one another, eventually going to the ends of the earth and back for each other by the story's end.
  • Twin Switch: The game and drops a lot of hints that the girl we know as Yua was actually her twin, Mia. The incident that gives her her DI-sword has her conclude that it doesn't matter which one she is.
    • Her character route in the NoAH confirms that they indeed switched places right before the incident. Because Mia suddenly didn't feel like attending an otaku meeting she was actually looking forward to (she's quite moody, to be exact), she convinced Yua of switching clothes so she can attend the meeting in Mia's stead.
  • UltimateGamer386: The protagonist himself.
  • Unreliable Narrator:
    • The start of the story is entirely from the perspective of the delusional main character, and he's not sure what's going on.
    • Everyone is an Unreliable Narrator in this show. Both the pseudo-scientific and pseudo-religious explanations are likely the results of each character's own delusions: Sena, as the main source of technobabble is the occupation of her father, which ties in directly to her incredibly traumatizing childhood; Ayase, who is the main source of the pseudo-spiritual explanation, is shown reading a book in the hospital entitled "The Gladioul Saga," which chronicles the tale of the battle against the Wicked-Hearted King Gladioul and the Seven Black Knights, the latter is her name for the DI-sword wielders.
  • Unwanted Harem:
    • Averted. While the main cast set up consists of Takumi and the six lead girls, and official art usually depicts Takumi with them in a way reminiscent of a harem, none of them are actually after him romantically. Rimi does eventually fall in love with him though and vice versa, as show n in the true ending.
    • When Takumi is mind broken by Suwa in the B Ending of the game, he plunges himself into a delusion of having a romantic comedy-like relationship with the girls at school.
  • Utopia: What Norose wants to create using Noah II. He wants to create essentially a delusion synchro that overtakes the senses of all humanity which will erases any bad events in the world from their sight and fulfill all of their hopes and desires without fail. This will also prevent the Committee of 300 from ever being able to rule the world, achieving everlasting peace. Unfortunately, Takumi destroys Noah II so this reality will never come to pass.
  • Updated Re-release: Chaos;Head NoAH, for the XBox 360. Changes to the game include adding routes for each of the girls and changing it to widescreen. They also changed the route system; you now have to finish each route to unlock the True Ending, which can then be directly selected from the Main Menu.
  • Virgin Power
  • Visual Novel: Described by the development team as "a Delusional Science ADV".
  • Vomit Discretion Shot: Takumi throws up after being pushed to his mental limit of being stalked and driven to paranoia by Shogun and NOZOMI. The details of him being described aren't mentioned though he does say that he throws up.
  • Wham Episode:
    • The entirety of Chapter 6. It begins with an earthquake that kills and injures hundreds of people and made most of the people in the city pass out, Ayase tries to kill herself and Takumi manages to save her with his delusions (unconsciously), Sena interrogates Takumi after this, Nanami is kidnapped and Takumi is forced to go to O-Front and nearly dies trying to obtain his DI-sword in the process.
    • The entirety of Chapter 9. Takumi sees a delusion of his sister, wrestles with the truth that he's a delusionary existence which makes him try to kill himself, Rimi tries to fight Norose and is kidnapped, Yua is nearly killed by a porter but obtains her DI-sword, Shogun tells Takumi the truth about why he was created, Takumi obtains his DI-sword and outs Hazuki as the New Gen culprit who proceeds to kill herself, and the city is subsequently destroyed by a massive earthquake caused by Noah II.
  • Wham Line:
    • Chapter 1:
    Yua: Shogun is none other than, you yourself.
    • Chapter 9:
    Rimi: In the entire world, you have nowhere to go home to, Taku.
    • Also Chapter 9:
    Shogun: The Third Melt?! Earlier than planned!
  • What You Are in the Dark: No one would know that Takumi had a chance to rescue Nanami, but instead he gave into the pressure and ran away if he never told anyone, and the guilt of doing this begins to slowly eat away at him. He redeems himself when Rimi is put into a similar position of danger, and he doesn't falter again.
  • Wrong Genre Savvy: Sometimes Takumi thinks of himself as a character in an RPG.
  • Yank The Gods Chain: Hatano experiences this when his baby daughter, Mana, dies for unknown reasons while he is taking care of her. This also happens in the middle of the experiment on his wife. He grieves, but ultimately fights to keep his wife in the experiment to prevent her from having to grieve for Mana and acknowledge her death. This lasts for 2 years until the plug on the experiment is pulled. His wife commits suicide and his last remaining daughter is dragged off to a psychiatric ward by NOZOMI, losing him his entire family in one fell swoop.
  • Younger Than They Look: Shogun is a high school student. Takumi is a year and a half old.

This is the delusion I wished for.