Seven years ago, Yuuto Amakawa's parents died, leaving him living alone without a single relative. Ever since then, his childhood friend, Rinko Kuzaki, has woken him up, cooked for him and generally taken care of him. The only thing he has from any relative is a mysterious charm, a red omamori, an amulet, given to him by his grandparents as a good luck charm.On the day of his 16th birthday, this charm's power to protect Yuuto from the Ayakshi wilts and loses the power to protect Yuuto, and into Yuuto's life walks Himari. A cat spirit and samurai girl, she swears to protect Yuuto, who is revealed to be the sole descendant of a family of demon hunters. Unfortunately, Yuuto is allergic to cats. More unfortunately, there are many demons after Yuuto's life. Fortunately, many of those demons are Cute Monster Girls who end up falling in love with him.Written and illustrated by Hentai artist Milan Matra, Omamori Himari is a Harem Series with lots and LOTS of Fanservice. It was serialized in Monthly Dragon Age from July 2006 to September 2013, spanning seventy-five chapters and already managing to hit every major Fanservice trope by around chapter 28.A Light Novel adaptation was published in July 2008, and sold four volumes until January 2010. An anime adaption aired in January 2010, animated by Studio Zexcs. And good news for English-speaking fans: the manga has been licensed by Yen Press for an official translation and has hit the shelves as of November 2010, with an Explicit Content rating. A four-panel comic adaptaton, called Omamori Himari: Himari's Panties, was serialized in Dragon Age from November 2009 to November 2010. Another side comic adaptation, called Omamori Himari: Book of the Gaiden, was released on September 9, 2011.The anime can be viewed legally at Crunchyroll here.Now has a character page that Needs More Love.
A-Cup Angst: Rinko is very uneasy about the size of her breasts - especially since three of the other girls after Yuuto are C-cup or above. One of them is even a T-cup.
As the series goes on, his willpower seems to be decreasing in this regard... it's getting to the point that the main thing keeping any given girl from seducing him is the other girls, who are very, very good at interrupting.
Kagetsuki: "He is one dedicated Goody-Two-Shoes. That is not to say I don't appreciate your egging him on." Shizuku: "Shut up...you know. He's just too passive."
Actual Pacifist: Yuuto is very close to this, at least partially. He really doesn't want to hurt anyone, and only does so if it is a matter of life and death... But still, he does let Himari fight for him, making her (and, at least in a way, himself as well, being her master) a Technical Pacifist.
Affably Evil: Shuten-douji. He had a (rather one-sided) casual conversation in his fight.
All There in the Manual: Volume 0, which is a collection of one-shot stories illustrated by different authors as well as including a recap of the story so far and character biosnote Volume 0 was released after Volume 5, so it only includes the story up to that volume..
Art Evolution: From the first chapter to somewhere around chapter 20, Yuuto looks, to say at the least, pretty weak. From there on, the art seems to get better and better, and it especially becomes more noticable in the later chapters like in chapters 50 and above.
Artificial Riverbank: In anime, the site of the first encounter with Shizuku. In the manga, it's a river in a small forest (or very big park?).
Beach Episode: Even with some plot progress. Shizuku's first attack, to be precise.
Berserk Button: Himari has a Heroic BSOD when Yuuto is severely injured while she is trying to guard him. She has feelings for him and has an oath to protect him with her life; push both of those buttons and you will get hurt.
For Kuesu, do not call her out on her family's heritage, and especially don't harm her beloved Yuu-chan, or else she will bring <Death> upon you. Shizuku and Shuten learned this the hard way.
In the anime's final two episodes, it doesn't even take a actual threat — just to IMPLY one is enough.
Bodyguard Crush: And it doesn't conflict with Himari's "sense of professionalism" at all... Although, for some odd reason, while she has no qualms about pushing Yuuto down to try to seduce him whenever possible in the most obvious ways, she barely manages to talk when she asks for a kiss later.
This is lampshaded by Himari, being a cat, not being familiar with human intimacy. Though, after a Accidental Kiss, she quickly wants to experience more.
Boring but Practical: Kuesu's magic attacks take some time to charge up and are highly directional. That's why she also relies on a plain old handgun.
Breaking the Fourth Wall: When Yuuto knocks Himari out of the path of danger and ends up groping her in chapter 47, his reaction...
"Ah... there was a scene like this in chapter 1."
Brutal Honesty: Shizuku has this tendency. She shamelessly lampshades her appeal to lolicons, and in one instance, after Yuuto fainted in a bathtub, and woke up fully clothed:
Rinko and Himari: "I didn't see anything!" Shizuku: "They had a good look at everything."
Himari: "Why did you have to hug him naked?" Shizuku: "It made me...... feel so good...... Don't make me say such embarrassing stuff."
Cat Girl: Himari. Played for laughs in that Yuuto happens to be allergic to cats.
And there's the scene where Himari swallows a medicine pill that would heal her, but initially would "shut down" her human side and make her go completely primal. Yuuto was worried at first that she would turn violent or be in pain, but as he hilariously found out, Himari's mind was merely turned into that of a playful cat, and with Yuuto right in front of her, she had her fun.
And in Book of the Gaiden, Hime. Too bad it didn't end well for her in the end.
Clingy Jealous Girl: Pick a girl, any girl, in the de facto harem. Lizlet is the only exception (she's still clingy when she sees Yuuto, just not jealous of others).
Rinko gets incredibly jealous and mad at Yuuto when Himari first shows up, and challenges her to some sports. And loses quite badly. She also gets mad at him whenever the other girls try to seduce him.
Himari herself experiences this when Kuesu first appears, and kisses him twice. Despite trying to ignore it, it bothers her so much that Himari demands that Yuuto give her a kiss as well. She will also occasionally leave her cat ears/tail out to "punish" him, such as in chapter 14 after three of the girls smother him while "training" him.
It happens again later — once to Himari, when Tama first shows up, and then again to Ranka Mikari. Both times, though, it's just a slash to the top, enough to show the bra underneath but not enough to actually remove the top.
Cool Gate: Kuesu later creates one from her hotel room to the closet in Yuuto's room.
The Corruption: Himari absorbing Tama's evil youki in chapter 63 has caused her to slowly undergo this. She eventually gave into it as of chapter 69 when she and Tama's Co-Dragons attack Yuuto's school.
Couch Gag: Who will Rinko find in bed with Yuuto at the end of the opening this time?
Yuuto was one of these as a child according to Rinko. Of course he got better.
Crouching Moron, Hidden Badass: Lizlet — a ditzymaid waitress who is strong enough to toss a human really high... with ONE hand, and then jumping up to join him! And probably even more impressive: She's a tsukumogami, and her apparent body is just a manifestation of the ghost of an old British tea cup. "Hurting" it ruins her clothes (at best), as you need to destroy her real body to hurt her — the tea cup. Still, she seems far less badass than most of the others around, even in her better moments.
Cute Monster Girl: Pick a girl, any girl, except for Rinko and possibly Kuesu — who is a witch instead.
Cute Mute: Tama. Subverted; she's devouring fellow youkai and demon hunters to increase her own power. And she doesn't really care if they're dead or not before she starts eating. And what's more, by the time she's done feeding, she turns out to be a Kitsune, and has already acquired Nine Tails, making her an Eldritch Abomination!
Class Rep: "...But my sixth sense is tingling..... it's telling me there's danger near. If something happens here, I'll be the first to die... (Like a Christmas murder...)" Kuesu: "Ohoho! The candle that burns twice as bright, burns half as long."
Defeat Means Friendship: Played straight and flipped around (Friendship means Defeat): Yuuto's wide-open heart and absolute belief that fighting is not the way to solve problems is enough to stop fights and win over another girl to the harem.
Don't You Dare Pity Me!: Being a warrior who respects honor, Himari occasionally takes offense to Yuuto's kindness when something bad happens to her.
Dude He's Like In A Coma: Near the end of the manga, Yuuto goes into a slumber for days to allow his consciousness to search for Himari, who sealed herself away in order to prevent her evil side from resurfacing. When he finds her and returns to his body, he awakes to find out that over half of his harem had their way with him in his sleep. Specifically, Kuesu, Shizuku, Lizlet, Ageha, and Aya were involved, along with Tamamo no Mae's flunkies from the last battle, Kurozakura. Finally, Rinko, the class president, and Kaya walk in on them, and are highly unamused at what they see.
Emotionless Girl: Shizuku — her facial expression almost never changes... almost.
Enemy Mine: Ageha and Sasa, who attempted to kill Yuuto in chapters 10-12 and episode 4, team up with him after they find out Tama is killing and eating Ayakashi. This takes a lot longer in the manga than in the anime.
Even Evil Has Standards: In Chapter 50, after learning Tama has mind-controlled the Class Representative/Yuu Shimamura and is hatching a plan, Shuten-douji silently expresses distaste for using the human as a hostage.
Evolving Credits: The girl in bed with Yuto when Rinko walks in during the opening changes every episode, usually whichever girl(s) gets the focus that episode. Sometimes the closing credits show slightly different images, or has one main girl singing throughout the song rather than splitting it between the 5 of them.
Expressive Hair: Shizuku's hair grows when she fights Kuesu, and shrinks back after the fight. It's probably related to anger, but it's hard to tell with her being an Emotionless Girl.
It is later shown again in her fight against Ranka Mikari, where she actually does show her thirst for revenge.
Expy: Himari looks like many of Matra Milan's main heroines from his early professional eromanga works — take Kanari from Palladium Garden. Kuesu is ripped straight from a character of the same name in Palladium Garden.
Fantastic Arousal: It's heavily implied that Lizlet's teacup body is actually quite sensitive in this way. Averted by Himari, whose cat tail and ears are no more sensitive than the rest of her body.
Heavily implied? More like outright confirmed when Yuuto drinks from Lizlet's teacup. Her reaction to Yuuto stirring sugar into his tea is like she's receiving some serious foreplay. Her reaction to him putting his lips to the cup is even more explicit.
Fantastic Racism: All fanservice-and-comedy said and done, monster or not, one has every right to hate someone when their family has taken everyone you love away from you. How he or she acts on that hatred, on the other hand...
And even between Japanese Inquisitors, the very act of learning Western Magic will earn you nothing but contempt and mockery amongst supposed allies. Just ask the Jinguuji family.
Faux Paw: Comes standard with catgirls, and Himari is no exception.
First Girl Wins: At least three possible interpretations — Kuesu was the first girl Yuuto kissed (once before his memory was sealed away with his powers, twice after, and only THEN comes a kiss with Himari), Rinko was the first girl Yuuto met when he moved out to live on his own and the first to interact with him in the story, and Himari was the first girl to be shown in the manga. Right now it seems that the series is going in the direction of having Yuuto and Himari be the Official Couple. Not surprising, considering that her name is in the title...
Forgotten Childhood Friend: Well, they aren't villains, but both Himari and Kuesu had been forgotten by Yuuto at the beginning of the story. Much to the consternation of both. To be fair however, the Protective Charm his grandparents gave him to hide his presence from Ayakashi also suppressed his childhood memories.
Gainaxing: Sorry, Rinko and Shizuku, you're the only odd ones out.
Game Within a Manga: In chapter 37, second panel, Yuuto's playing a video game...of Himari fighting Shizuku.
Gas Leak Coverup: Used to explain the damage caused by the fight between Kuesu and Shizuku. When Kuesu learned of the coverup on the news, she commented that this was the first time she'd heard of someone installing gas lines on the TOP of a building.
Gecko Ending: The anime ended at 12 episodes, with the final two bringing to a end two major villans whose plotline is still unresolved in the ongoing manga (at the time). The final two are original to the anime, obviously.
Genius Bruiser: Kuesu packs the most power out of all the haremettes despite being human (just ask Shuten in his last bout with her) and has the most brains due to her mastery of dark magics and as a result of coming in contact with a forbidden Great Big Book of Everything while studying in England.
Genre Savvy: The Class Representative, who thinks that Rinko should throw herself onto Yuuto, because the girl who did that in a harem game she played won!
Good Thing You Can Heal: Subverted: Himari, who does heal faster then a human, is only injured in serious fights. Shizuku, who seems to have "dissolve into water and reappear" as standard reactions to injuries like, um, BEING SLICED IN HALF manages most of her fights (well...3 of 5) without a scratch, and Lizlet, whose body is invincible, just got stabbed twice in one fight. Basically, the better you heal, the less often you get injured...
Harem Nanny: Kisaragi-sensei fits this, at least on her very rare appearances.
Healing Factor: Rather minor compared to other examples, but it's mentioned several times that Himari heals faster than humans. It still takes her usually at least a day to recover (from injures that probably would take weeks for a human).
How Do I Shot Web?: All information on how to use the Light Ferry was passed from father to son in an oral tradition. Unfortunately, since Yuuto's father and grandfather both died before passing the information down, he doesn't know anything about how his powers work and has to figure it out from scratch.
Improbably Female Cast: Ok, it is an Unwanted Harem, but seriously: In 70 chapters so far, 9 males were allowed to speak. One wasn't even named, both Shizuku and Kuesu have someone who works mostly as a messenger to other demons and Demon Slayers respectively, another got an Unsettling Gender-Reveal, another is a one-person version of Those Two Guys, then there is the male villain, and, at last, the protagonist. The most guys talking in one chapter was three, and that happened only once.
Intimate Healing: After Yuuto gets stabbed in the back in a fight, Shizuku proclaims that her water magic can be used for healing and, well, does so while Himari is looking on.
In a later chapter Himari gets covered in snow after battling a grown-up Tama at a ski lodge and tries to get Yuuto to do the "warm up via shared body warmth" routine. To her extreme disappointment, he takes her to the lodge's hot springs instead.
Invisible to Normals: There are spells that ward off humans, and "Public Safety Division 4" cleans up the mess afterwards.
James Bondage: The only reason Himari doesn't need to CONSTANTLY rush out to save Yuuto is that she's usually already with him and can save him right away. Still, it happens.
Katanas Are Just Better: Played straight by Himari. Justified by the fact that her sword is a legendary sword. Not that this keeps it from being completely fried by a certain witch, but it makes the "repairing" of said sword harder..
Keigo: Probably how Himari speaks. Some scanlators reflect this by rendering her speech in Ye Olde Butcherede Englishe. The official English translation is smarter and more subtle about it by having her not use contractions as well as having her speech be more elaborate than that of the other characters.
Kill the Cutie: Hime, a fellow cat ayakashi Himari befriended, at the end of Book of the Gaiden because the Amakawa family's law dictates that any cat ayakashi under them who falls to her primal instincts must be killed on the spot. Thus Himari was forced to kill her when she saw her consuming the flesh of a human girl whose grandmother was once her owner. Also counts as a Tear Jerker moment for Himari.
Lolicon: Shizuku is fully aware of her appeal to lolicons ("Few human men can resist a little girl's form like this.") and even declares at a few points that there is "only room for one loli" in the series.
Lens Flare Censor: In the anime's TV broadcast. Averted in the DVD (and much later, Blu-ray) version.
Limited Wardrobe: Averted with most characters, but played straight with aome. Lizlet and Himari are the most prominent examples.
Masquerade: More as a side note. The "Public Safety Division 4" usually keeps things secret in Japan and works together with the Demon Slayers. Other nations are stated to have similar groups.
Meganekko: She's only a side character showing up from time to time, but the class representative fits perfectly.
Meido: Lizlet, and Himari when she's working at her part-time job.
The Messiah: Yuuto just wants everyone to get along. As long as there's a chance that his enemies can be reasoned with, he'll hold off from fighting. Even when he wins the following battle, he tends to spare his opponents. He also gets drawn into people's problems pretty easily and devotes his efforts to helping them.
Morality Chain: Yuuto is this in various degrees, to various characters.
Himari nearly falls into a blood rage several times — stopping herself since Yuuto wouldn't like it.
Kuesu would love to exterminate all demons on earth, even the innocent ones — but doesn't, since Yuuto would hate her for it.
Shizuku would have killed the (innocent, powerless) descendant of the Demon Slayers that annihilated her clan, but stops for the same reason as Kuesu.
This is what finally causes Yuuto's power to manifest in the concluding episodes of the anime...after the climax, he can no longer use his power consciously. He or someone he cares about must be in mortal danger. In the manga, he's unable to use it unless threatened from the very beginning. He learns to use it by choice instead of instinct in fights, but still needs real danger (to him or others) to do so.
Subverted: Himari is a white cat, and as a girl...it changes to black. Lampshaded by Yuuto in an omake.
Yuuto: "Shouldn't you stay white, since it's easier to draw?"
The same omake explains that the hair color was inspired by another character's (Kuesu).
In the anime, Himari undergoes a further transformation in the final two episodes, when supposedly she gives herself FULLY over to her demon side. Her hair changes to white, her WHOLE BODY sprouts fur and gains marks, and her head/face become decidedly more cat-like. CRAZED cat-like, with red eyes.
My God, What Have I Done?: After Yuuto confronts Kuesu in chapter 21 about his reasons not to marry her due to her unwillingness to coexist with Ayakashi, she attacks him with a knife, causing his Light Ferry ability to activate. She gets thrown out of the hotel room due to its force, and Yuuto suddenly remembers a forgotten memory with her where he wanted to protect her and help her defeat Ayakashi. He begins to regret everything he just told her, as she held onto his promise all this time. Fortunately for him, she manages to teleport herself back into the room, then tries to find some common ground with him so he wouldn't hate her so much, such as not attacking Himari.
Naked First Impression: Shizuku. It's not really a first impression, but it still kind of applies: After having fought her the day before, Yuuto finds her in his bathtub the next day... And while he faints shortly after, she keeps her usual expression
It should be noted that Yuuto is the one naked (taking a bath), while Shizuku wore as much clothes as usual...for her.
Nice Job Breaking It Heroes: Shared with Aiji and Kasuri in chapter 52. The two wanted to see how dark Himari's Superpowered Evil Side has become, for Yuuto's safety. When Kasuri uses her Magic Mirror spell to to reveal Himari's dark side and Aiji amplifies it to make it appear in the real world, it turns out to be so evil that it cannot be contained in Kasuri's mirror and said evil side escapes from the mirror and enters Himari's body. Nice job breaking it, indeed.
Not So Stoic: Shizuku barely shows any emotions other then smug and snarky, but when she finally realizes that her blind desire for revenge was ultimately both pointless and self destructive, she breaks down in Yuuto's arms.
Orphan's Plot Trinket: Well, it already loses importance and power in the first chapter, but Yuuto HAD a charm to protect him from demons for several years, and he's an orphan...
Our Vampires Are Different: Ageha's abilities as a Hinoenma is that she can suck blood (mostly from men) without any negative effects (other than the obvious things that come from losing a lot of blood). So she doesn't have to kill when she doesn't want to.
The Power of Love: Played more or less straight but without the Narm usually involved. Yuuto's absolute conviction that everyone can get along has a genuine effect on most of the characters. His sincere honesty makes them at least stop and think about their actions, if not outright reconsider their motives. Heck, he broke Shizuku out of something like 100 years worth of seeking revenge by refusing to accept her denial of friendship and a hug.
Protective Charm: Yuuto was given one by his grandparents to keep him safe from demons until his 16th birthday. As shown in the beginning episode 1 of the anime, it begins to weaken, and the demons slowly become aware of his presence and attack. Fortunately Himari also arrives to protect him as well. See Title Drop below.
Psycho Lesbian: Kaya. HEAVILY implied to be this way in terms of her feeling towards Himari and her actions towards those who get in the way. Pretty much confirmed in volume 0 when she's seen sniffing Himari's underwear.
Psychic Link: Tama seems to be unable — or unwilling — to communicate in any other way. Slowly averted in later chapters.
Though it's never actually explained what it is. It might be anything from Mindlink Mates to actual telepathy. Or Shuten-douji is just the only one who knows her enough or is observant enough to note what she means.
Puberty Superpower: Yuuto's demon-hunting powers were supposed to have awakened when he turned 16. His powers took a little longer to manifest, however.
This may more accurately qualify as Dangerous Sixteenth Birthday, since that was merely when the seal on his powers wore off. And the day of his sixteenth birthday was also when he began to attract ayakashi who were after him.
Really 700 Years Old: Shizuku with an age of at least 100 years. She explains her household skills by noting that before the destruction of her clan, daily chores like cooking and cleaning were more important than fighting... Said destruction was about 100 years ago. Also Lizlet to a lesser extent, since she manifested from a tea cup after 100 years of activity.
Refusal of the Call: It's said that other Demon Slayers sealed their abilities, as did Yuuto's parents (specifically his father since his family's abilities are passed down to the male side), probably. Yuuto himself is thinking about it.
The anime gives her both her normal forms from the manga, a true form that can be viewed as terrifying, and an enhanced form when Yuuto uses his powers on her in the climax. Both of the last forms are in the two episodes that do NOT use manga chapters as the plot lines.
"Shut Up" Kiss: In chapter 66, Yuuto gives one to Kuesu after listening to her condition, too bad that Himari saw them.
Single Gender Race: Himari's ayakashi species (Bakeneko, or "monster cat") only births females.
Single-Target Sexuality: Himari is "only interested in [her] master" and her body "belongs to him alone." And now add several attempts of her to seduce him.
Himari gets this occasionally as well... such as in chapter 36.
Hitsugi Yakouin, at the bottom of the page in chapter 46.
Soul Jar: This is the actual "Badass"-part of Lizlets "Crouching Moron, Hidden Badass". Lizlet is by far not the only rather strong girl in this series, but being sliced and stabbed and just complaining about the ruined clothes? Being the manifestation of a sentient tea cup has its advantages.
Sprouting Ears: Himari can actually do this, but her ears and tail are enough to trigger Yuuto's allergies, so she only does so if needed...or to threaten him ("I shall let out my ears and tail and meow").
Actually, if sufficiently angered, she'll do more than threaten him...
Story Breaker Power: Yuutos inborn ability, Light Ferry, essentially increases the attributes of whatever he wants. There seems to be no limit on what he can increase or how far the increase will go. Its heavily implied that if he had full control of his power he'd be invincible.
Superpowered Evil Side: The "Berserker"-version. Shizuku warns Yuuto that basically any demon, no matter how "civilized", might lose to its instincts, even Himari and herself.
In the anime, Himari does just this in the final two episodes to defeat Tama and Shuten-douji. BERSERK doesn't even begin to spell it out — she becomes destructionpersonified. Yuuto snaps her out of it with a hug and The Power of Love.
Supporting Harem: Out of all the girls, Yuuto cares about Himari the most. Not that it stops the others, especially Rinko and Kuesu, from trying to hook up with him.
In the manga, they're actually pretty much on equal footing. Of course, Himari's still the only one with her name in the title...
Thanks for the Mammary: It's a Running Gag that this happens every time Yuuto falls onto a girl. Unusually for this trope, the girls often don't mind. Himari only objects if he does it during a battle or training session.
Thou Shalt Not Kill: Yuuto doesn't want anyone to get hurt. Most other characters are less friendly.
In the anime, He finally recognizes that he can't save everyone, and uses Light Ferry to power up both Himari's sword AND HIMARI, in order to kill Shuten-douji.
Which quickly becomes a Title Drop since Himari's role in the story is to protect Yuuto from ayakashi that seek to kill him after his protective charm (called an omamori in Japan) stopped working. In other words, she is Yuuto's new protective charm, or Omamori Himari.
Token Mini-Moe: Shizuku and Tama (introduced in chapter 28 of the manga). Lampshadedand enforced by Shizuku whenever another little girl appears:
When Himari is transformed: "There's only room for one loli in this house." (accompanied by strangling her) After Tama appeared: "I'm the only loli allowed in this area."
As of chapters 41 and 42, Tama no longer applies all the time, being able to temporarily assume a curvy adult form. She reverts in chapter 43, and Shizuku repeats her objection.
Training from Hell: Yuuto tries this once with Shizuku, but without success — since she can't bring herself to actually hurt him, the training doesn't work. Then, Lizlet, Rinko and later even Himari show up, and it turns into Training FromMarshmallowHell...
The training he now recives from Himari seems much less severe, though.
Transfer Student Uniforms: Himari keeps her "old" school uniform (or at least a different one) to warn demons who plan to attack Yuuto that she is there to defend him.
Traumatic Superpower Awakening: Yuuto's Light Ferry ability seems to work on this principle, at least early on before he can summon and control it at will. Shizuku even points this out to him in chapter 14 and episode 5 during their mock battle, where it didn't activate due to her unwillingness to really attack him and put him in real harm's way. Unlike when Ageha attacked and sent Himari into an Unstoppable Rage, and later with Kuesu attempting to stab him after he rejects her marriage proposal.
Rinko is a bit of this, being mostly nice (Type B) to Yuuto... Except when something gets in her way. Not enough for a Yandere, though.
Also Ageha, the Hinoemnma, as a Type A. What makes her different from a Yandere is that her "Males are food" attitude is NORMAL for her, and her sympathy (as far as there is any, as she's VERY tsuntsun) only goes so far as to not trying to kill Yuuto. Oh, and wanting to rape him.
Unusually Uninteresting Sight: People who aren't fooled by the Masquerade and don't get hit with Laser-Guided Amnesia from mindwiping spells will... not seem to particularly question why Shizuku appeared out of a lake or why Yuuto, Himari, and Rinko are talking about witches (demon slayers) all of a sudden.
Or the Big Damned Sword being carried by the extremely buxom, old-fashioned-kimono-wearing Himari.
Subverted by the Genre Savvy Class President, who's noticed the strangeness of Himari's enrollment and the phenomenon that keeps occurring.
Van Helsing Hate Crimes: The Demon Slayers want the ayakashi dead. Sometimes, there are minor exceptions and a demon gets spared, which led Himari's ancestors to serve the Amakawa family, but mostly...
Wham Episode: Chapters 11 and 12 of the manga and episode 4 of the anime, when Yuuto and Himari run into Ageha, the first Ayakashi that doesn't want to reason with him unlike others he's run into so far. He also gets seriously injured, causing Himari to go into an Unstoppable Rage.
Kuesu (to some degree) for Yuuto, although that's more arrogance and a ploy to forcefully awaken Yuuto's power and reawaken his memories, she becomes Tsundere after that. In chapter 21 and episode 8 of the anime, however, she clearly has that look in her face that many other females who fall into this trope have when she attacks him..
Also, both Himari and Shizuku can be violently crazy (yan-), but that's (mostly) unrelated to their feelings for Yuuto (-dere), so while the name fits, they aren't actual examples.
Ye Olde Butcherede Englishe: At least in the fan translations, to emulate the archaic Japanese spoken by Himari in the original. It gets pretty bad. Later subverted in recent fan translations.
Youkai: Part of the basic premise of the entire manga is that these exist, and are trying to kill Yuuto. Except for the ones who fall for him, of course. Which seems to be most of them so far... of the female ones at least. Even Tama, when she took on her adult form, made a pass at him.