Literature / The Zashiki Warashi of Intellectual Village

20 Minutes into the Future, to compete with cheap products from other countries, Japan created Intellectual Villages. Taking old fashioned rural villages and recreating them with cutting edge technology, the nation fostered designer and brand name products made with high tech tools and traditional methods. The program is a complete success, and now a third of the country resembles the rural Japan of the pre-industrial era. As an unintended side effect, the youkai of Japanese folklore have emerged from seclusion, resettling in the Intellectual Villages or wandering through them as their natures dictate.

Shinobu Jinnai is a student in one such village, and has a Zashiki-warashi living in his house. His tendency to attract youkai is getting him involved with the Packages—criminal operations that make use of a youkai's supernatural powers—that are on the rise in his sleepy country town. Uchimaku Hayabusa is Shinobu's police detective uncle living in Tokyo, who winds up investigating crimes involving youkai while dodging the affections of Hishigami Enbi. Hishigami Mai is a supernaturally empowered mercenary for hire, whose biggest client wants her to investigate organized criminal (and international) interest in Packages across several major cities and the Intellectual Villages.

Needless to say, the incidents are all connected, and building up to something bigger than anyone has yet realized.

Another light novel series by Kazuma Kamachi, author of A Certain Magical Index. It is complete at nine volumes, though Kamachi has released a series of small bonus stories on his official website.

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Tropes found in this series:

• Abhorrent Admirer: Enbi to Hayabusa. She's actually quite attractive, and if her sister is any indication, she'll grow up to be an exceptionally lovely woman. Unfortunately she has No Social Skills and is also in middle school while he's a detective.
• Achievements in Ignorance:
  • As a child Shinobu would happily invite any youkai he met to be his friend and play with him. Majina noted that in doing so he was essentially "defusing" dangerous youkai such as a God of Poverty, an act Hyakki Yakou struggles to achieve even once.
  • Majina claims it's a sign of just how prosperous the Jinnai Brewery is that they were able to suppress the Ver. 39's calamitous power.
• A Child Shall Lead Them: Hafuri, the leader of Hyakki Yakou, is ten years old.
• A Dog Named "Dog": All youkai default to being called their species name. Even the title character, though she does have a proper name (it's Yukari).
• All Just a Dream / Alternate Timeline:
  • Volume 5 Side-A. The rest of the book is about preventing it from coming true.
  • In Volume 9 Shinobu is forced to experience the death of his alternate self in multiple timelines where things diverged.
• Alliance of Alternates: In the climax of Volume 9, Shinobu is separated from Bloodstained Yukari by countless barriers, each of which forces him to experience his death in alternate timelines. The agony of moving through even a small fraction nearly breaks him but it also summons the spirits of all those alternate Shinobus who share the burden so he can succeed where they failed.
• And Now for Someone Completely Different: Volume 4, which has the deuteragonists narrates instead of the usual three.
• Awesomeness by Analysis: How the situations get resolved. The characters try to figure out how a Package operates, what youkai are involved and how to break the curse (or amend the curse to work in their favor) before it gets them killed.
• Bad Future: Volume 5 Side-A, ten years later: the world is in the middle of a combined energy crisis and food shortage, the only proposed solutions are mining the Moon or Mars, both of which are impossible with their current technology. Oh, and Shinobu's a Mad Scientist who actually manages to kill Mai.
• Bad Liar: A tanuki shapeshifts to look human so he can get some kitsune udon. Despite this everyone can tell he's a tanuki and points it out, despite his stammering protests that he's definitely not a tanuki and even made sure his tail was hidden.
• Bedmate Reveal:
  • A particularly funny one since the revealer isn't sleeping (just distracted). After reading his Singer Song Liar story, Shinobu realizes that he's being used as a pillow by Hafuri and Hishigami Mai.
  • In Volume 8 Shinobu wakes up and is terrified to learn the Aoandon had snuck into his futon, though she snarks it's completely normal since he's her father. Then he notices there's somebody on his other side... the Aburatori.
• Brick Joke: Early in Volume 9 Majina laments that his greatest fear is that after he dies Shinobu's allure will lead to him bedding both Majina's wife and daughter. Later on Shinobu witnesses several alternate timelines, including one where he did just that... and got punched by Majina's ghost after it escaped hell.
• Casual Danger Dialogue: Most of everything Mai says. Shinobu's not bad either, but he's got a ways to go.
• Chekhov's Gun: The keychain with ocean water from Shinobu's story in volume 2.
• The City vs. the Country: Youkai hate cities, and are attracted to the rural atmosphere of the Intellectual Villages.
• Class Representative: Surprisingly, Shinobu.
• Close-Enough Timeline: Happens twice, first in Volume 4 then in Volume 7.
• Complete Immortality: All Youkai have an immortal body, since they don't have a concept of lifespan. They are also immune to conventional weapons and physical damage that follows the laws of physics, to natural poisons and to things like radiation.
• Cute Monster Girl: Being a youkai series, there's lots.
• Days of Future Past: Less of an example than most, as the aesthetics is only limited to the Intellectual Villages.
• Deity of Human Origin: Volume 2's antagonist is looking to make and control one.
• Delayed Narrator Introduction: Works as The Reveal at the end of Volume 3, to hide the fact that the Aoandon is still alive and at large.
• Doomed Hometown: All Japan at the end of volume 5 Side A.
• Downer Ending: Subverted twice. In Volume 3, it is even Lampashaded by the author:
  Afterword of Volume 3: "If this was primarily a horror series, it might have ended here."
  • Then in Volume 5, it is revealed that the events leading to a Bad Future never took place.
• The Dreaded: The Aburatori, even by other Youkai. The Aoandon has a similar reputation to the point that the CIA is willing to destroy Japan rather than let it live.
• Driven to Suicide: In Volume 9 it's mentioned that many politicians and investors, realizing the world is likely days away from a violent collapse, have been secretly hiring assassins to kill them painlessly.
• Eaten Alive: The fate of the time-travelling Shinobu after crippling the Aoandon.
• Enter Eponymous: The chapters of volume 1, introducing each three protagonists with chapters titled "Regarding (name)".
• Expy: Inverted. Word of God says in the afterword of the first volume that the concept of Intellectual Villages were created using the exact opposite process of Academy City from A Certain Magical Index, as the Villages are essentially a very rural but just as technologically advanced counterpart to Academy City.
• Fanservice: The cover art and most of the monochrome pictures.
• Fission Mailed: The ending of Voulume 5 Side-A. In Side-B, Shinobu finishes reading the story only to find out it was a prediction of the future brought on by a Package. The author calls it the "worst ending" in the volume's afterword.
• Foreshadowing:
  • Volume 4 features a past incident involving a young Shinobu, with some background events carrying on such as his uncle apparently foiling a criminal scheme. It's also stated the events taking place here have been altered from the original timeline. Volume 7 reveals the actual incident was caused by the criminals abducting Shinobu, leading to the Aburatori's near-rampage.
  • Throughout volume 5, references are made to a "blue light" that the CIA and America are combating. It's a reverse English translation of Aoandon, which means "Blue Lamp". And at the end of the novel, the Aoandon is free to start her plan.
• Future Me Scares Me: In the Bad Future of volume 5, Shinobu is a Mad Scientist who is using the Succubus to seduce and control many women, and kills Mai with a demon powered robot. All in the name of love. According to the author, Shinobu was not born to be a hero, so he can easily head down such a path.
• Godzilla Threshold: Anything that makes Mai pull out the Deadly Dragon Princess has crossed it. Making her use a gun means she's 80% of the way there. This is because Mai herself is stronger than the Deadly Dragon Princess; being forced to rely on it or a gun means she's so outmatched that neither the shikigami or a gun will matter.
• Gondor Calls for Aid: In Volume 9 Shinobu sends out a call to every youkai he has ever met to come and help him save Yukari, forming his own Hyakki Yakou.
• Gone Horribly Right: Hyakki Yakou attempted to convert Yukari into a tool through which they could manipulate destiny. While their efforts indeed made her capable of this, they also inadvertently connected her to a force of entropy and endings which uses her power to bring about terrible calamities.
• "Groundhog Day" Loop: In Volume 3, one is created in Zenmetsu Village using small snake Youkai called Toubyou. Their ability being to steal whatever is necessary beyond distances and coordinates, Mai speculates it also allows them to grab objects from the past or future, making them capable of forcing all people inside an area known as the "jar" (where everything is actually made of Toubyou: grass, ground, trees, asphalt, buildings, fog, mountains, the sky, etc) to go through an endless loop as they created the 100 riddles for the creation of the Aoandon. If 100 riddles were not created within a given period of time, the landscape would turn back into an endless swarm of Toubyou, crush the survivors and loop them back to the moment they entered the Package with their memories intact. If all participants were killed before the timer ran out, the loop would also restart, but their memories would be wiped, forcing them to start from zero. The protagonists spent countless loops inside, and once freed they simply appeared in reality as if no time had actually passed from the moment they had been abducted.
• Hitman with a Heart: She'll never admit it, and spends entire pages monologing how it's not true, but her actions prove that Mai is not as heartless as her words or her reputation say. She never considers killing an American diplomat and his Gentle Giant bodyguard, and even offers the former a possible solution to avoid a Curse he picked up while averting a food crisis in Africa.
• Hopeless Suitor: Enbi to Hayabusa. It's not just the age gap, she's completely hopeless when it comes to human interaction that doesn't involve a murder investigation.
• Human Sacrifice: "Mikuchi-sama" in Volume 8 originated when villagers threw the bodies of those who died during a famine into a pit in the nearby mountain to prevent disease. This transformed into a legend that the mountain was a deity which would release a plague on them if it was not given regular sacrifices. The villagers started using it to execute criminals but soon extended it to the injured, the sick, and even political rivals. The sacrifices never stopped, either, as up until ten years ago the "Shinto" priests on the mountain were actually kidnapping travelers and preparing them as sacrifices.
• Humans Are Bastards:
  • Most of the stories have human villains, with the Package youkai merely being a tool they utilize.
  • As youkai are born from human myths and emotions, they often serve as living examples of this trope. For example, the Aburatori was created to explain the disappearance of children murdered by their parents.
  • Shinobu realizes that the Aoandon is simply a reflection of its human "parents" who created its one hundred stories. Because they were so violent, hateful, and despicable, she was born knowing only the negative sides of humanity and so believed it best to destroy it.
• Hyper-Competent Sidekick: Enbi to the detective.
• Idiosyncratic Episode Naming: The chapters of the light novels usually follow the pattern of "Short Japanese Text + POV character", though each volume do it differently. There are exceptions to the rule, mostly the volumes focused exclusively on Shinobu like Volume 5 and Volume 7 (though the chapters themselves can contain Switching P.O.V. and Multiple Narrative Modes, even if Shinobu's Point of View is the dominant).
• Implicit Prison: Youkai are tied to Japan and can't live in other countries without recreating the environment of Japan there.
• Insistent Terminology: At least in the fan translation, large criminal organization is used for yakuza.
• In the Blood: The Hishigami family tends towards creation and chaos. That is, male descendents are good at making connections and female descendants are good at breaking them.
• Japanese Delinquents: Shinobu, though it's only in appearance. His uncle Hayabusa was the same in his youth.
• Just Before the End: In Volume 9 the world economy is in a seemingly unrecoverable death spiral, the people of Japan are losing touch with reality due to a massive influx of money, and the other nations are about to wipe the island nation from the face of the Earth. The fallout from this seems almost certain to result in the complete extinction of humanity.
• Killer Rabbit: No matter how small and adorable a youkai may be, at the end of the day they're still a quasi-immortal spirit which often has extremely deadly abilities not obvious at first glance. As an example, the sunekosui Ohatsu may be an adorable dog, but by accessing her origin as "fear of what's in the dark", she can turn into a lethal living shadow.
• Magic Must Defeat Magic: Youkai are immune to any kind of damage involving the laws of physics. Natural poisons and radiation do not affect them and even the weakest youkai could survive a downpour of nuclear missiles. As such, other magical and supernatural abilities are needed to defeat youkai, and Hishigami Mai needed ot have her body thoroughly remodeled via extensive surgeries to develop superhuman abilities and the power to bypass a youkai's invulnerability.
• Monster Roommate: The Zashiki Warashi's link to the house they inhabit qualifies Yukari. Later on, more and more (female) youkai come to live in Shinobu's house.
• Nebulous Criminal Conspiracy:
  • Hyakki Yakou is the most powerful secret organization in Japan, but the only things that are known about them except that they "work to overcome the fear of youkai".^note Fear in this case means both negative perceptions of youkai, and their supernatural powers. They're just as interested in experimenting on how to use youkai powers as they are in putting a stop to criminals abusing them. They sometimes function as antagonists because they're willing to go nuclear to prevent particularly dangerous Packages from getting out of control. Additionally, they are the original owners of the Zashiki Warashi Yukari.
  • "Large criminal organizations" are one of the main antagonists of the story. The extent of their size and power varies, with some almost rivalling Hyakki Yakou. One of their main weapons is the creation of "packages" to conduct and coverup their more mundane crimes.
• The Needless: Youkai have no real need for food or water, though they do enjoy it.
• Nice Job Breaking It, Hero: Hafuri and Shinobu nearly caused the end of the world due their decision to save Yukari's Ver. 39 power.
• Nigh-Invulnerability: Thanks to being unaffected by physical attacks and most of the laws of physics, youkai are pretty much immortal and unkillable.
• No Name Given: Most youkai. Several human characters are also nameless like Hyakki Yakou's top 5 members, Shinobu's classmate Love King or Hishigami Mai's supplier. The name of the person who ordered attacks on Mai in volume 4 is also unknown since she refused to give it.
  • The seventh volume gives the name of the Succubus, Henrietta, and the final volume finally gives us the Yuki Onna's name, Hyou.
• Noodle Incident: Shinobu has several, like the time he was nearly drowned by a mermaid who sent him a love letter, a middle school incident that led to a fight with real swords and drove his childhood friend Nagisa to become a yandere, and the reason said friend has stabbed him. Twice.
  • His uncle's first meeting with Hishigami Enbi and the first case they worked together, the Glass House Case, was one until it was later given a complete summary in a side story.
• Nouveau Riche: The entire county of Japan becomes like this in Volume 9 when the global currency crisis results in massive amounts of money being funneled into their economy. Everyone runs around spending ridiculous amounts of money on luxury and pleasure without any thought to what will come tomorrow. The more level-headed Japanese panic when they realize this could very easily distort people's understanding of money and destroy their economy.
• One-Gender Race: Some Youkai species, like the Yuki-Onna, consist entirely of individuals of one gender.
• Person of Mass Destruction:
  • Hishigami Mai. Enbi has the capacity, but is suppressing her nature after falling in love. Actually every woman born to her family, to the point where daughters are killed as a preventative measure. Exactly how two Hishigami women survived and escaped has yet to be said.
  • In the last volume, this is what Yukari is one by becoming the Bloodstained Zashiki Warashi, the state a Zashiki Warashi reaches when she leaves or predicts the downfall of the house she inhabits. Since her powers were augmented by the Hyakki Yakou, she had the power to unwittingly end mankind.
• Only One Me Allowed Right Now: After a bout of time travel end with two Shinobus present, the time traveler instinctively realizes that he cannot exist in the same time as his counterpart. As such he puts up no resistance when the Aoandon devours him.
• Our Demons Are Different: Demons can be summoned by humans by establishing a contract with them and performing a ceremony, which automatically bars the human's soul from ever entering Heaven. The human needs to know the true name of the demon in order to create the contract, so demons only tell their true names to those they trust. Of course, the summoner should be careful and not summon a demon too strong for him or her to control. Also, demons don't actually have physical bodies (save rare exceptions like Succubi who can create one for themselves to interact with humans). Because of that, they needs a vessel to interact with physical matter when summoned to the human world.
• Our Fairies Are Different: Fairies are another type of monsters in this world. While benevolent fairies like Caladrius (a small bird who heals sick people by absorbing their sickness) exist, other fairies can be dangerous to humans who want to harness their powers, like Rusalka, Nixie or Leannán Sídhe.
• Polluted Wasteland: The chemical factories of Japan are made to leak and/or explode at the end of volume 5 Side-A, changing the archipelago into no go zone where only Youkai could live.
• Post Modern Magick: Packages are essentially curses that you can break or amend to work in your favor.
• Precocious Crush:
  • Middle-schooler Hishigami Enbi for Uchimaku Hayabusa, much to his dismay. She's constantly trying (and failing) to seduce him.
  • Young Shinobu didn't bother hiding how much he adores "Yukari". This threw her off balance as much as she throws him off in the present.
• Reasonable Authority Figure: The leaders of the Tokyo police are unable to act freely due to politics and public opinion, but they're more than ready to offer Hayabusa covert advice and support to see justice done.
• Red Herring: In Volume 4 a young Shinobu is the victim of an organ harvesting Package which used a diet drink as a vector. Later dialogue reveals that history had been modified, obscuring the actual nature of the incident. When the original history is revealed, the drink is shown to have existed but was completely unrelated to the incident.
• Rich in Dollars, Poor in Sense: Shinobu's classmate Kotemitsu Madoka in a nutshell.
• Ridiculously Cute Critter: Animal type Youkai can be this in their true shape, sometimes being mistaken for stuffed animals. Sunekosuri are a perfect example since they look like 30cm tall Shiba Inu. The son of the Sunekosuri who acts as Mai's sidekick is only a 5cm tall puppy.
• Rotating Protagonist: Most volumes follow the general layout of Shinobu (first chapter), then Hayabusa (second chapter), then Mai (third chapter) and then Shinobu again (fourth chapter). The first three chapters introduce seemingly-separate plotlines, which then come together (along with the three protagonists) and are resolved in the fourth chapter. Volume 4 is a notable exception, instead using perspectives of the deuteragonists (Yukari for Shinobu, Enbi for Hayabusa and the Sunekosuri for Mai), though it still follows Shinobu for the fourth chapter.
• Sadistic Choice: Ten years prior to the story, the Zashiki Warashi was told she could save children who had had their organs mystically harvested, or she could save the beneficiaries of those transplants. A young Shinobu was a victim of the harvesting, making the choice that much more painful. She chose to save them all, at the cost of her powers.
• Semantic Superpower:
  • The youkai known as Funa Yuurei is a species of ocean Youkai with the power to sink ships. Modern humanity might have things like tankers and aircraft carriers, but the Funa Yuurei continue to sink them just as easily as they did with wooden ships in the past.
    Hayabusa: Common ways of thinking don’t apply with them. If they can sink ships, they can sink any ship. It doesn’t matter if it’s a luxurious cruise liner or an aircraft carrier.
  • Youkai in general have powers with clearly defined rules that can be exploited to create "packages". For example, a Yuki-Onna will kill anyone who agrees to marry her. Write a contract that states anyone who resides in a room agrees to marry the Yuki-Onna, whether they read the contract or not, and she will appear to kill them.
• Serial Escalation: The first few volumes focused on more personal and small-scale incidents but starting with Volume 5 the destruction of Japan itself was threatened, each time with increasing severity. This culminates in the final volume where the world itself was at risk.
• Set Right What Once Went Wrong: In Volume 7 the Aoandon is on the verge of wiping out the Japanese but the only weapon that could stop her was lost when the Zashiki Warashi broke its power to save Shinobu. To prevent this, Shinobu is sent back in time to resolve the incident and preserve the power to stop the Aoandon.
• Seven Deadly Sins: The Succubus is friends with a demon who is said to almost rank as one of the demons who symbolize the sins. It's later explained the list of Seven Sins was arbitrarily created and only included demons whose sins were easily explained. The Succubus's friend wasn't included because her power is too broad and difficult to quickly describe despite debatably being more terrifying than a Sin.
• Shapeshifting: Several Youkai can assume a human form, namely Kitsune, Tanuki, Mamedanuki, Mujina, Kijimuna and Furutsubaki. The Nekomata is also capable of the human transformation, but needs to have bitten someone to death to do it.
• Shipper on Deck: Hishigami Mai is apparently very supportive of her sister's seduction of an adult man. She still wonders why they can't just get married already.
• Shout-Out: Volume 7 has an extra illustration depicting Yukari, Hyou, Mai and Enbi wearing the clothes of the main characters of A Certain Scientific Railgun, reciprocating the Shout-Out of chapter 74's cover in the Railgun manga.
• Smarter Than You Look: Despite his bleached hair, Shinobu does well in school and is his class's representative. Appropriately, he's been nicknamed "Intellectual Yakuza". It shouldn't be that surprising that he's an Evil Genius roboticist in the Bad Future of Volume 5.
• Starving Student: Hayabusa receives a care package of high end Intellectual Village vegetables and rice but he has no idea how to cook. He gives them to his college student neighbor, who cheerfully exclaims she no longer needs to rely on soaking instant ramen in water to infinitely double its size.
• Stripperiffic:
  • The Succubus's outfit.
  • To a lesser extent, but even more troublesome, Enbi. She wears swimsuits as casualwear, and switches to a bunny outfit in volume 5.
• Succubi and Incubi: The Succubi and Incubi are the same existence, with Incubi attacking women after getting the seed from men as Succubi. They can manipulate dreams.
• Swallow the Key: Shinobu steals and swallows a key part of Aoandon's body to reduce her power. She responds by first trying to chew through his neck to get it back and, when that doesn't work, goes for his guts.
• Switching P.O.V.: The viewpoint changes very frequently; aside from the Shinobu -> Hayabusa -> Mai -> Shinobu layout mentioned under Rotating Protagonist, it will often switch to a minor character or even to the third person perspective.
• Sympathy for the Devil: At the end of Volume 9 a crying child asks Shinobu to help him save Tselika from an arranged marriage. Even knowing it's likely a trap, Shinobu agrees because this is the first time in thousands of years that somebody has wanted to save Tselika.
• Take a Third Option: Using her power to control destiny, Yukari managed to avoid a Sadistic Choice (see above), at the cost of losing said powers.
• The Call Knows Where You Live: And when you go on vacation. Or are having a mixer. Justified by youkai loving Shinobu (he's a natural Package target), and by Enbi's crush on Hayabusa (she's a mystery freak).
• The Unmasqued World: In this universe, monsters and other supernatural creatures are the norm. Besides youkai running around Japan, there's a Succubus who formed a cult revolved around her and desire in Europe, a German company is researching fairies and medicines, and Australia engages a Witch to look for a method to pacify what they think is an angry Aboriginal god.
• Time Is Dangerous: In Volume 7, the person who uses the Kudan's time travel package automatically return to the present after making one change. While the person is shielded, any object or person they hold will instantly experience the passage of however many years lie between the two times which will kill anything living. Youkai still experience the passage of time, but due to their ageless and needless nature won't die. Shinobu exploits this to let the Aburatori instantly fulfill the requirement of going nine years without killing to becoming a kaeshigami.
• Time Travel: A Plot Device twice:
  • First in Volume 4, in which an Aburatori gained time travelling abilities after taking over a Package that had interpreted his trait of appearing anywhere he wants without anyone seeing him as time travel. He would serve as an antagonist to Yukari ten years in the past as she tries to save a young Shinobu from him, then in the present by desiring to obtain Yukari's ability to manipulate destiny.
  • Once more in Volume 7, this time using a Package around the Kudan. The Kudan can predict what will occur in the near future with 100% accuracy, but as there are no records of what point in time is defined as the present, it is used to redefine the Kudan’s present to a set date and thus allow one person to travel to any point in time. This allows Shinobu to travel to the past to try and solve the original incident of Volume 4 with Yukari and the Aburatori that had forced her to sacrifice her powers.
• Timey-Wimey Ball: The events surrounding the Aburatori incident in Shinobu's youth are something of a mess and only fully explained in Volume 7. Originally the Aburatori saved a kidnapped Shinobu but almost gave into his urges, traumatizing Shinobu. He asked Yukari to rewrite history to make him a villain to spare Shinobu, creating a timeline where he was indeed a villain who nearly killed Shinobu until Yukari rewrote reality in that timeline. Ten years later, Shinobu was sent back to the original timeline and prevented the original rewrite by taking the Aburatori to the future.
• Tricked Out Time: Majina learns of his impending assassination due to a time-traveling character. Forewarned, he fakes his death and remains in hiding until he catches up with history and can re-emerge without causing a paradox.
• Tsundere: Jinnai Shinobu to all youkai, but particularly to Yukari.
• 20 Minutes into the Future: The tech level is slightly more advanced than ours, Intellectual Villages have been a thing for at least 30 years, and Japan has recovered from his low brithrate (the population is now of 150 millions) and its GDP is second in the world. An offhand comment from Yukari about how the end of the Edo period was about 150 years ago would place the series around 2018 at the very least.
• Unusual Chapter Numbers: Volume 3 only has one chapter, titled "Chapter ?: Welcome to Zenmetsu Village". The nature of the volume makes you realize exactly why it is such.
• Unwitting Instigator of Doom: Shinobu successfully becoming a couple with Yukari triggers the near destruction of the world as the Ver. 39 tries to "balance out" his good fortune.
• Used to Be a Sweet Kid:
  • Young Shinobu adored youkai as much as they adore him. All youkai. His attempt to save the Aburatori almost got him killed and Yukari rewrote reality to protect his innocence.
  • Nagisa was an adorable and timid child until she witnessed her parents working in their family farm's meat processing plant. This set her on the path to becoming one of the world's three great yandere.
• Urban Fantasy: The story takes place in a slightly futuristic Japan in a world where Youkai and other supernatural beings are known to exist and integrated into society to varying degrees.
• Villain's Dying Grace: Majina's existence created an imbalance in the world as he should be dead. While dying, he chooses to release that energy to restore Shinobu and the other victims of the volume to life.
• The Watson: Police detective Uchimaku Hayabusa is entirely competent in his field. Unfortunately, he's involved in youkai-related mysteries, so his chapters have him acting as this for the more supernaturally involved Enbi.
• Weirdness Magnet: Each male member of the Jinnai family, in different ways:
  • Shinobu attracts all kinds of Youkai. The ones that are capable of affection adore him.
  • Hayabusa is antagonized by Youkai (they see him as a Metal Slime of sorts)
  • Shinobu's father utterly terrifies them.
• What Do You Mean, It's Not for Kids?: Tends closer to the seinen genre rather than the shonen, what with Mai's rampages and the occasional supernatural massacre.
• Winds of Destiny, Change!: Hyakki Yakou Prototype Ver. 39 Zashiki Warashi. Better known as Yukari, or "that glamorous Zashiki Warashi". Apparently all Zashiki Warashi have this power in a limited form, but hers was artificially enhanced before she lost it Taking a Third Option in the past.
• Yandere: The Yuki Onna, as well as Shinobu's childhood friend Nagisa, who Shinobu claims is one of the world's top three yandere.
• Youkai: Besides the eponymous Zashiki-warashi, there are Yuki Onna, Nuroduke, Sunekosuri, Nekomata...
• You ALL Share My Story: In every novel, the disparate storylines eventually converge in the climax, where the protagonists join forces.
• You Are Number 6: Youkai registered with the Japanese government, the numbers they're assigned are the closest thing some of them have to a name. The Zashiki Warashi is #36110054Ra2 or alternately Hyakki Yakou Prototype Ver. 39 Zashiki Warashi, and the Yuki Onna is #58902385Ra4.
• You Can't Fight Fate: Majina survived an assassination attempt due to warning from a time traveler, but his continued existence created an imbalance as he should be dead. When he dies, the released energy is enough to mostly undo the disaster he had just engineered.
• You Can't Go Home Again: Shinobu and his family flee a contaminated Japan in the Singer Song Liar story, leaving Yukari behind.
• Your Mind Makes It Real: The goal behind Singer Song Liar/the Amanojaku Package, using the Amanojaku's representation of lies to make them a reality.

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