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The Koiwai Family
Our viewpoint character, a five-year-old with a very energetic outlook on the world.
- Adorably Precocious Child: Ziggzagged. There are times when she acts exactly like you would think a five year-old would act, then there are times she does or says things that you would expect from someone older. Though the things she says are sometimes played with as well since there are times it's obvious she's just repeating what she heard with no idea as to the meaning.
- Bad Liar: Not that she's noticeably worse than any other five-year-old. Props, though, for trying to use A Wizard Did It.
- Brutal Honesty: Due to her very young age, she sometimes makes very blunt and harsh comments, but with no intention to harm anyone.
- Cheerful Child: One of Yotsuba's main traits is that she can find excitement in anything. As it says in every chapter, "Today is always the most enjoyable day."
- Cloud Cuckoolander: Her dad thinks she's a little weird. When describing her to Fuuka, he says:Koiwai: "If you see a girl that makes you think 'It's a weirdo', it's probably her."
- Comically Missing the Point: She does this a few times. For example, because she doesn't understand why Jumbo asks her to invite Asagi along for things, she tends to fail and invite others instead.
- Constantly Curious: She is full of questions, especially when it comes to something new to her.
- Curtains Match the Window: In addition to her green hair, Yotsuba also has green eyes.
- The Cutie: Oh God, yes! Found to be both adorable and loveable by nearly everyone who meets her, and due to her young age she's naive (with a few Adorably Precocious Child moments) and always discovering new things.
- Daddy's Girl: Yotsuba adores Koiwai and spending time with him. When Fuuka asks her who she likes, she simply answers with "Daddy!", and when Fuuka tries to compare heartbreak to a mere scenario of Koiwai not liking her back, Yotsuba becomes incredibly teary and has to be reassured that he still loves her. Koiwai of course treasures Yotsuba more than anything else and liked her enough to adopt her in the first place.
- Drop-In Character: Constantly drops by the Ayases and treats their home like hers, even house-watching it once and welcoming in Torako like it's her house. Her and Mr. Ayase meeting for the first time lampshades it:Mr Ayase: "You be good friends with my girls."Yotsuba: "I am."Mr Ayase: "You can even come over every day."Yotsuba: "I do."
- Expressive Hair: Her pigtails rise and fall with her (rapidly changing) moods.
- Flower Motifs: Ever since the first manga volume, sunflowers have been used with Yotsuba to symbolize her "sunny disposition". Four-leaf clovers, to a lesser extent, since her hair is styled that way.
- Genki Girl: In spades. And the trump suit. This gets Lampshaded by Asagi: "Her default rate of movement really is running." In the Beach Episode Koiwai hangs a lampshade on her ability to keep going full-tilt right up until she uses up her last reserves of energy after she literally keels over fast asleep in the midst of building a sand castle.
- Girlish Pigtails: She has four pigtails, which along with her green hair is meant to resemble a Four-Leaf Clover (which in turn refers to her name).
- Happily Adopted: She doesn't care one bit about her parentage. Koiwai is "Daddy" and that's that.
- Hate at First Sight: Yanda tries to enter the house while her dad is away. Yotsuba has been taught not to let any strangers in when she's alone. Which leads to her slamming the door on his face. The fact that Yanda enjoys making her angry on purpose doesn't help improve her opinion of him.
- Improbable Hairstyle: Obeying the Rule of Cute, Yotsuba's hair is always in those four little pigtails, even when sleeping, swimming, taking a bath, etc.
- Instant Expert: In chapter 92, Yotsuba does ridiculously well in her first yoga session.
- Intergenerational Friendship: Other than the the little girl in later chapters named Mii-chan, Yotsuba doesn't have many friends her own age, with Ena and Miura being the closest in age at ten. Justified because she just moved to town and isn't in school yet.
- Malaproper: She mostly knows the words, but how to say them is still a little beyond her.
- Meaningful Name:
- Yotsuba means "four leaves" as in "Four-Leaf Clover". Thus her hair.
- "Yotsuba" and "Koiwai" are also both brands of dairy products in Japan, and a whole chapter is centered around drinking milk.
- Missing Mom: She was an abandoned child prior to being adopted and even now only has Koiwai as her father. It doesn't bother her though - she's more than content with Daddy and doesn't understand the concept of having both a mum and a dad.
- Mistaken Nationality: Based on her appearance, strangers constantly assume Yotsuba to be a foreigner, and indeed she was born in another, unknown country. As a result, some students at Fuuka's school try to speak to her in English because all gaijin are American.
- Nice Girl: She's sweet to everyone she meets. Except Yanda.
- Parental Abandonment: We know nothing about her origins except that Koiwai found her somewhere overseas, which Yotsuba claims was "an island 'to the left'". When asked about her mother, Jumbo bluntly says with a straight face that Yotsuba was abandoned as a child. She isn't bothered when he says it, but the Ayase girls freak out over it.
- Plucky Girl: Delivering milk is Serious Business.
- Sitcom Arch-Nemesis: Hers is Yanda who finds enjoyment in purposely annoying her.
- Sunny Sunflower Disposition: She's such a Genki Girl, she appears with a bouquet of sunflowers in the cover of the 1st volume. A later chapter even sees her fascinated by sunflowers in Jumbo's shop, and wanting to buy some.
- Super Drowning Skills: Surprisingly averted, Yotsuba can swim quite well. Koiwai, Jumbo and Fuuka on the other hand...
- Third-Person Person: Childishly, in the original Japanese (mimicked in the Yen Press translations); she combines this with an innocent imitation of her father's masculine language — the effect is hysterically funny but is, alas, Lost in Translation.
- Trademark Favorite Food: As expected for a five-year-old, Yotsuba really likes ice cream. She also has a fascination for cup ramen. Curry is another favorite — one of the songs on the Image Album is called "Eating Curry (Very Delicious)".
- Why Did It Have to Be Snakes?: Yotsuba is terrified of anything that has huge eyes, or anything that looks like a huge eye. Ironic considering her own are pretty big.
- You Gotta Have Blue Hair: Green hair in her case, which makes her an oddity among the cast's otherwise realistic character designs.
Yousuke Koiwai / "Dad", "Daddy"
Yotsuba's adoptive father, who works from home as a translator. He's devoted to her, but isn't exactly the most driven parent who ever lived.
- Bishōnen: A downplayed example. He has long, shaggy hair which, when combined with his skinny build and the Only Six Faces nature of the artstyle, makes him look quite feminine, particularly when alongside Jumbo. He is also noted by Fuuka's classmates to be fairly good looking.
- Brutal Honesty: As a part of his deadpan persona, he can be rather blunt and tactless when talking to others. For instance, when Fuuka and Shimau came over to invite Yotsuba for a yoga session, his immediate response was to ask them how much weight they've put on.
- Catchphrase: Important announcement!
- Children Raise You: Koiwai calls himself "irresponsible," but he all but admits that raising Yotsuba has forced him to get his act together, at least a little.
- Cuteness Proximity: Put a guinea pig in his vicinity and he just melts. It's been suggested this may be part of the reason he adopted Yotsuba.
- Deadpan Snarker: Usually when bulling around with Yanda, but sometimes in response to Yotsuba.Koiwai: It says "No admittance."Yotsuba: Even for me?Koiwai: What, are you a VIP?
- Good Parents: So very much. He prioritises Yotsuba at all costs, never condescends to her and never dismisses what she says. He will discipline or tell her off when appropriate and won't spoil her too much but he takes genuine interest in her ideas and is often willing to treat her to something new, whether it be pizza or the zoo.
- Hypocrite: Despite his anger over Yotsuba lying to him, he himself frequently lies to her, though they are small white lies or pranks.
- Nice Guy: He's laid back and pleasant with everyone he meets, making him be on generally good terms with the entire cast.
- One of the Kids: He frequently behaves in a childishly over-the-top manner when interacting with Yotsuba, but otherwise he's a normal (if slightly irresponsible) adult.
- Reasonable Authority Figure: He's quite willing to tolerate, if not participate in, Yotsuba's sillier antics. On those occasions when she does actively misbehave, the hammer comes down hard — sometimes overlapping with Scare 'Em Straight.
- Sempai/Kohai: He is Yanda's senpai - whether from work or school is unknown.
- The Slacker: He doesn't even wear pants in the summer, if he has the choice.
- Super Drowning Skills: He, along with Jumbo and Fuuka, cannot swim, and will immediately drown when pushed into deep water.
- Supreme Chef: In Yotsuba's eyes anyways, he makes pretty good food. When she mentions some of the food he makes to Jumbo and Yanda they look genuinely jealous (especially Yanda).
- Troll: He has his moments, such as telling Yotsuba that the blue paint she's covered with will never come off and that she's "going to be blue from now on".
- Unnamed Parent: His given name wasn't revealed for the longest time; even Jumbo calls him by his family name. It was finally revealed in Chapter 87.
Koiwai's mother and Yotsuba's grandmother. She lives in the countryside, and Koiwai and Yotsuba lived with her before moving to their current home. Grandma looks and acts stern but she's absolutely worshipped by her granddaughter.
- Cool Old Lady: Grandma comes all the way to the city to watch a concert, all dressed up in trendy clothes, then single-handedly stops Yotsuba from headbutting her. She also has a bit of fun trolling her granddaughter by making her run errands for a souvenir, then pretending that there aren't any. And if that's not cool enough, she reveals that she bought a smartphone, and knows how to use it. And she gloats about that to her son. She's considered awesome by both fans and in-universe characters, and probably the reason why Yotsuba adores her so much despite being quite strict.
- The Ghost: Though never seen until Chapter 86, she's often mentioned by Yotsuba or her dad up until then. They even briefly talk to her on the phone in two chapters, though she's obviously not heard by readers. Her husband, Yotsuba's grandfather, has been mentioned but not seen, being absent when she comes to visit the Koiwais.
- Granny Classic: Of the sterner kind. As the Koiwais lived with her before moving, she helped bring up Yotsuba too and so is a secondary parental figure. She also showers Yotsuba with presents (or is supposed to, according to Yotsuba's logic), has bought her clothes, brings fruit when she visits, and is stern enough to scold her granddaughter when need be but also shows clear adoration for her.
- Kansai Regional Accent: Appears to speak with the Kansai dialect. For example she once says "[...] een chauka?" ("wouldn't it be fine to [...]?") which would be the Kansaiben way of saying the standard "iin janaika?". She confirms it in chapter 88, having been under the impression she'd got rid of it.
- Perpetual Frowner: Yotsuba introduces her to Fuuka as such:Yotsuba: Grandma looks like she's mad, but she's really not. She's always like that!
- Troll: When Yotsuba asks for a souvenir, Grandma first says she doesn't have any, then says she tricked Yotsuba and gives her pears as her souvenir, to Yotsuba's annoyance. Then she gives Yotsuba her real present, which are coloured pencils and a sharpener.
- Unnamed Parent: To Koiwai. She's only known as Grandma or Grandma Koiwai.
The Ayase FamilyThe Koiwais' next-door neighbors, frequently visited by Yotsuba.
The oldest Ayase girl; Yotsuba looks up to her (figuratively and literally). She seems to enjoy it.
- Alliterative Name: Asagi Ayase.
- Cool Big Sis: Yotsuba admires her very much, and likes clinging to her more than she does her sisters.
- Cuteness Proximity: She gets this every so often around Yotsuba.
- Dude Magnet: Not that she notices, but Jumbo and Yanda both fall hard for her.
- The Gadfly: Likes pulling pranks on people, or using Yotsuba to pull pranks on people.
- Hidden Depths: She is actually really good at fixing Teddy Bears, even ones with an electrical voice box that had been soaked in water.
- Like Father, Like Son: Gender-inverted. Her father lampshades this when Mrs Ayase complains about Asagi's personality becoming worse, saying Asagi acts like how she was when younger. Though both will strenuously deny this.
- One of the Kids: She is able to follow along with Yotsuba's train of thought better than anyone else.
- Romantic Two-Girl Friendship: Asagi and Torako do pretty much everything together, including going on long trips. Yotsuba's description of the two's relationship sounds like they are girlfriend and boyfriend.
- Sweet Tooth: She gets it from her mother. They sometimes clash over it.
- Tomboy and Girly Girl: Girly Girl to Torako's Tomboy. Asagi's an easygoing girl in very feminine clothing while Torako is an aloof girl with Boyish Short Hair and much less feminine clothing and traits. It's gone as far as Jumbo thinking Torako's a guy by judging her from Yotsuba's pictures and description.
- Troll: Yotsuba spends a whole day excitedly waiting for Asagi to bring her a gift, but upon returning from her trip Asagi pretends to have no idea what she's talking about. It's not until Yotsuba is dejectedly walking away that she pulls out a bag of fireworks.
- The Unfavorite: She and her mother do not exactly get along, played mostly for laughs.
The middle Ayase girl, and the one who seems to have the worst luck. Her travails, of course, go right over Yotsuba's head.
- Berserk Button: Don't call her fat or mention her weight. Just don't. Jumbo (and Koiwai) find out the hard way in the pool chapter.
- Big Ol' Eyebrows: Though Koiwai in chapter 67 thinks this just makes her cuter.
- Butt Monkey: She frequently takes the brunt of Yotsuba's Brutal Honesty and Jumbo and Koiwai's teasings. She also seems to have terrible luck. Some examples:
- She gets stuck in the Koiwais' bathroom window when they first moved in.
- She wakes up late when Yotsuba came to bring milk to her family, and misses the good stuff.
- Her crush gets together with another girl, and Yotsuba's attempt to cheer her up makes things worse. And she also asks Yotsuba to keep it a secret - cue the next day when she wakes up to Yotsuba's newspaper that blatantly has written all over it "Fuuka has heartache" and everyone in her family is reading it.
- Dreadful Musician: Fuuka, drop that ukelele. And stop singing.
- Friend to All Children: Especially prevalent during the Autumn festival.
- Generation Xerox: Takes after Mr. Ayase, notably his romanticism and love of puns (much to Asagi's chagrin).
- Go Nagai Sideburns: Her hair seems to give this sort of visual effect, kinda like Kagura.
- Incredibly Lame Pun: Her sense of humor leaves much to be desired.
- Is That Cute Kid Yours?: When Yotsuba visits her at school, Fuuka's classmates wonder if Yotsuba is her child.
- Joshikousei: She's a high school student and so is often seen in her sailor uniform.
- Ms. Fanservice: Shows off a lot more skin than any other female character, including wearing short skirts, swimsuits and turning up in sexy outfits on colour pages.
- Pungeon Master: Of the incredibly lame variety. Her father enjoys them, but Asagi and Jumbo don't.
- Ship Tease: Usually with Koiwai, Played for Laughs, due to quite a few (non-perverted) Not What It Looks Like situations between the two. One classmate even asks her other classmates once if he's her husband.
The youngest Ayase girl, she's the closest to Yotsuba in age and thus plays with her most often. Likes bugs, amphibians, and teddy bears.
- Adorably Precocious Child: Mature for her age, especially when compared to her sisters and mother.
- Berserk Button: Don't do anything that isn't environmentally friendly, or keep calling any of her bears "Duralumin".
- Cheerful Child: Although not quite at Yotsuba's level, Ena still generally has a sunny disposition.
- Cool Big Sis: The younger variety; Ena seems to go further than Fuuka or Asagi in treating Yotsuba as a little sister.
- Daddy's Girl: Though Mr. Ayase loves all of them very much, Ena seems to be his little girl. He goes as far as saving up his last handmade Father's Day back massage voucher from her to use for her wedding day.
- Encyclopaedic Knowledge: She has a lot of random knowledge about a great many things such as stars. Sometimes justified as it relates to her school work.
- Girls Love Stuffed Animals: She likes playing with her teddy bears with Yotsuba, and screams when Yotsuba uses one of them as a weapon in a fight with (a disguised) Miura and accidentally rips its arm a bit.
- Girly Girl with a Tomboy Streak: Ena dresses in a girly fashion and loves doing tea parties with her teddies. She is also not afraid of frogs, bugs or other icky animals and she doesn't hesitate to take the inner organs of a fish. All of these freak Miura out.
- Granola Girl: She tends to be more environmentally conscious than others as well as having a fondness for recycling, but she doesn't mind eating meat or helping clean fish for a meal.
- Hidden Depths: She really likes experiencing new things, even if it may be unpleasant like cleaning and gutting fish.
- Nature Lover: She really likes the outdoors.
- Tomboy and Girly Girl: She looks like the girly girl to Miura due to her feminine looks (in contrast to Miura's boyish attire), but has some tomboy interests and more boyish personality than Miura does, such as liking frogs and being brave enough to gut fish (while Miura... is terrified of frogs and gutting fish).
The mother of the three girls. She's always seen in the Ayase house and is affectionately called "Mom" by Yotsuba.
- Abusive Parents: Played for Laughs in her treatment of Asagi - even in a flashback, after a young Asagi found a four-leaf clover for her, she told her daughter she'll only be satisfied if she finds a five-leaf clover, which nearly sent the girl to tears.
- Housewife: She's always seen inside her house, usually preparing food in the kitchen or doing laundry.
- Like Parent, Like Child: She and Asagi are quite alike, but don't tell either that. Mr Ayase lampshades this when Mrs. Ayase complains about Asagi's personality becoming worse, saying Asagi acts like how Mrs. Ayase was when younger.
- Parental Substitute: Acts as a surrogate mother figure towards Yotsuba.
- Sweet Tooth: She seems to be fond of foods like ice cream and cake. She once sends Yotsuba, Ena and Miura to buy cake mainly because she wants some.
- Team Mom: Besides being the Ayase girls' mother, she's also a minor maternal figure to Yotsuba. She often takes care of her and treats her the same way as her own daughters whenever she visits their house such as feeding her. Yotsuba even calls her "Mom", and she automatically thinks of Mrs. Ayase whenever mentions of a mother are made to Yotsuba. She also treats Miura the same way as her daughters whenever she comes over.
- Unnamed Parent: Her given name has not been revealed so far.
- Why Did It Have to Be Snakes?: She looks visibly terrified when Yotsuba releases a bunch of cicadas in the house.
The father of the three girls. He's not seen at home very often due to his busy work schedule.
- Disappeared Dad: He's rarely at home because of his work, and Asagi frequently pretends he's already dead because of it. Played for Laughs, though.
- Eyes Always Shut: His eyes are rarely opened. One occasion where he opens them is his Blue with Shock Papa Wolf reaction to finding out about Fuuka getting her heart broken.
- Generation Xerox: Fuuka takes after him, notably his romanticism and love of puns (much to Asagi's chagrin).
- Papa Wolf: Shows signs of this when Yotsuba hands out her newspapers which blatantly has written on them "Fuuka has heartache". He warily asks Yotsuba who the boy is and he tells Fuuka that he won't let anyone break her heart.
- Salary Man: The reason he's rarely at home.
- Satellite Character: Does not have much characterization aside from being the girls' father. He only appears in a few chapters when the Ayase household is involved, and has very few lines when he does.
- Unnamed Parent: Like his wife, his given name is completely unknown.
Takashi "Jumbo" Takeda
Koiwai's best friend, whose nickname hints at his most notable feature. A decent guy, if a little overenthusiastic around Asagi.
- Achilles' Heel: Miura is able to manipulate him by saying she'll mention how good or bad a person he is to Asagi.
- Alliterative Name: His real name, Takeda Takashi.
- The Big Guy: He is enormous, both in height and in breadth.
- Big Ol' Eyebrows: Just like the rest of him.
- Childhood Friends: Implied with Koiwai. In the stargazing chapter, he mentions that he's taking them to a field that he and Koiwai went on a field trip to when they were children. Also, he's probably the closest friend Koiwai has. Yotsuba seems to think that he's his only friend, as stated in Yanda's introductory chapter.
- Failure Is the Only Option: Any time he tries to get Yotsuba to invite Asagi on an outing. It usually results with another Ayase girl or two going in her stead.
- Friend to All Children: He gets along well with kids, especially Yotsuba who adores him. Helps that he is practically a child in mentality himself.
- Gentle Giant: He's a florist and a Friend to All Children.
- Hopeless Suitor: Has a large crush on Asagi, but she doesn't notice.
- Hot-Blooded: He's overly eager about many things especially if competition or Asagi is involved. Moreso than others, and he shares it with his dad.
- In-Series Nickname: Koiwai, Yotsuba and Yanda have always called him Jumbo and so everyone else refers to him as such after meeting him.
- Jack-of-All-Trades: He is pretty knowledgeable in a lot of areas as seen whenever he and the gang go out to do different activities such as stargazing and fishing.
- One of the Kids: Gets into a rivalry with a ten-year-old girl over going to Hawaii.
- Only Known by Their Nickname: Jumbo, referring to his terrific size, in contrast to his real and rather plain name Takeda Takashi.
- Phrase Catcher: "You're huge!"
- She Is Not My Girlfriend: He corrects his dad after he assumed Fuuka was his new girlfriend.
- Sitcom Arch-Nemesis: Seems to be actually trying to be this with Miura, by competing with whatever she's doing (such as going to Hawaii).
- Unrequited Love: He has fallen for Asagi pretty hard, but he can barely talk to her, let alone ask her out.
- What the Hell, Hero?: Koiwai calls him out on using Yotsuba to try and ask Asagi out, though this fails every time.
Ena's friend, who's not all that nice to Yotsuba (though she doesn't actively try to be mean; she just doesn't have everyone else's patience). Hates slimy things, in contrast to Ena.
- Bifauxnen: She has short hair and wears boyish clothes. Not long after Jumbo first meets her, he has to ask if she's a girl or a boy.
- Brutal Honesty: She tends not to keep her opinions to herself, and once pointed out that Yotsuba's drawing is terrible, almost driving her to tears.
- Cool Toy: She keeps amazing Yotsuba with various things, such as Heelies, a unicycle and a push scooter.
- Jerk with a Heart of Gold: Miura has a tendency to play mean pranks on Yotsuba (e.g. appearing before the latter in an eyeball mask after discovering that Yotsuba is afraid of eyeballs), but despite this, she is good friends with Yotsuba and Ena.
- Lovable Coward: She is easily frightened, and cannot stand bugs, snakes, frogs or anything slimy. Nevertheless she is Yotsuba and Ena's good friend.
- Miko: Dresses for the part during the Autumn Festival.
- She Cleans Up Nicely: Pulls this off as one of the matsuri maidens during the autumn festival and thus has a more feminine touch to herself than usual. The gang comment that it suits her and makes her look cute.
- Shorttank: She prefers sports clothing to tanktops, though.
- Sitcom Arch-Nemesis: Jumbo tries to be this with her by teasing or competing with her, though she only sometimes takes the bait.
- Strong Family Resemblance: Miura looks a lot like her mother, and upon meeting both of them many characters have commented on it even though Miura disagrees. Yotsuba even calls her mother "Big Miura" when she first meets her.
- Tomboy and Girly Girl: She looks like the tomboy due to her short hair and boyish clothes, but Ena is actually more tomboyish than her personality-wise such as liking frogs and willing to gut a fish (in contrast to Miura being absolutely frightened by either things).
- Tomboy with a Girly Streak: She's a mischievous tomboy, but has some girly girl interests, is surprisingly squeamish and has a distaste for anything slimy and gross.
Asagi's friend, she has a somewhat more aloof personality. Yotsuba seems to confuse her even more than the rest of the cast.
- Aloof Dark-Haired Girl: Dark hair and a composed and stoic demeanour - part of the reason Yotsuba thinks she's cool.
- Beauty Mark: Has one on her neck.
- Bifauxnen: She's rather androgynous due to her short hair.
- Boyish Short Hair: She has short hair and lacks any girlish traits.
- Cool Big Sis: Yotsuba thinks she's cool at first sight. Later in the series Torako actually teaches Yotsuba how to tie bow knots.
- Defrosting Ice Queen: She initially acts cold towards Yotsuba, since she's not used to kids, but is beginning to open up to her antics.
- Every Girl Is Cuter with Hair Decs: Yotsuba ties one in Torako's hair after Tora taught her how; Asagi and fans all agree that she looks really cute with it.
- In-Series Nickname: Since her name looks like "Tiger Child" when written out, Yotsuba calls her Tora/Tiger.
- No Social Skills: Nothing all that serious, but she often proclaims not to be good with kids. Not that this keeps Yotsuba from liking her.
- Perpetual Frowner: The only expression outside of shock she shows.
- Romantic Two-Girl Friendship: With Asagi; when Yotsuba explains their relationship to Jumbo it sounds like they are boyfriend and girlfriend.
- Smoking Is Cool: Torako tells Yotsuba at their first meeting that she smokes because it makes her look cool. Yotsuba seems to agree.
- The Stoic: Perpetual Frowner is her default expression, though she'll show emotion when the situation calls for it (like Yotsuba setting off sparklers on her car).
- Tomboy and Girly Girl: Tomboy to Asagi's Girly Girl. Torako is an aloof girl with a Boyish Short Hair and much less feminine clothing and traits while Asagi's an easygoing girl in very feminine clothing. The punchline of chapter 77 specifically plays off this dynamic.
- Unknown Rival: Jumbo thinks "Tora" is Asagi's boyfriend thanks to a rather unclear description of her and her relationship with Asagi from Yotsuba.
Koiwai's kohai who gets a kick out of taunting Yotsuba. Unfortunately for him, everyone treats him exactly like he deserves.
- Butt Monkey: He brings it upon himself. As having Yotsuba as an archenemy means having Koiwai and Jumbo against him too, his friends don't hesitate to go along with Yotsuba and call him unreliable and a bad guy, and will nearly always side with Yotsuba.
- Chekhov's Gunman: He's mentioned fairly early in the very first chapter and receives a handful of mentions afterward, but doesn't appear in person until Chapter 30 where he and Yotsuba first establish their rivalry.
- Childhood Friends: Seems to be this with Koiwai - he not only recognizes his mother, but also addresses her as "auntie",note and she treats him in a reciprocal fashion.
- Drop-In Character: Frequently visits the Koiwais so he can mooch hot water for his instant ramen.
- The Ghost: As seen in Chekhov's Gunman, he's often mentioned but never seen until his debut in Chapter 30.
- In-Series Nickname: Koiwai and Jumbo call him Yanda, so Yotsuba does too.
- Jerkass: Yotsuba certainly sees him as one, because he not only steals her ice-cream, he takes back the candy he gave to her, and won't stop mocking her.
- Jerk with a Heart of Gold: Evolves to this trope, with him becoming nicer to Yotsuba.
- Kick the Dog: He initially went out of his way to be mean to Yotsuba, though he seems to be getting better.
- One of the Kids: This guy enjoys being Yotsuba's Sitcom Arch-Nemesis.
- Only Known by Their Nickname: His real last name is Yasuda, but no one calls him that. His given name is completely unknown.
- Perpetual Poverty: He barely even has money to eat well (living on a diet of mostly instant ramen), at least until the end of the month. His bad eating habits and barely paying his rent seem to be his only issues though, and he still manages to find money for things like bubble toys.
- Pet the Dog: While not as bad a guy as Yotsuba makes him out to be, he seems to enjoy messing with her a little to much. That said he is also the one who gets her out of her funk when she's worried about Duralumin, and shows her the awesomeness of bubbles.
- Salaryman: White shirt, tie and all.
- Sempai/Kohai: He is said to be Koiwai's old kouhai. It's unclear in what way, but it's probably from work at some point or at school.
- Sitcom Arch-Nemesis: Of Yotsuba, by doing anything he can to annoy her. He even seems to take delight in invoking the trope in regards to her.
- Straight Man: Thinks the way that Koiwai and Jumbo go along with Yotsuba's antics is incredibly weird. However he's Not So Above It All at times.
- Took a Level in Kindness: Starts behaving nicer to Yotsuba in chapter 72 when he brings over bubbles to show to everyone especially Yotsuba and let's her play with them.Yotsuba: Yanda, you're being nice today. Keep up the good work.
- Trademark Favorite Food: He practically lives off instant ramen.
- Tsurime Eyes: The corners of his eyes slant up to give him a more arrogant look. Appropriate for his obnoxious personality (towards Yotsuba anyways).
"Miss Stake/Shimauu" Hiwatari
A classmate and friend of Fuuka's. Her real name is Hiwatari, but acquired her nickname when flubbing her introduction to her class.
- Happy Dance: Initiated by Shimauu and followed by Fuuka and Yotsuba while baking a cake.
- Lost in Translation: The joke behind her nickname; in Japanese instead of introducing herself to the class with the standard "Yoroshiku onegaishimasu" ("Please take care of me"), she accidentally said "Yoroshiku onegaishimau" ("Please accidentally take care of me/ please take care of me with regret")note which lead to her nickname Shimauu. The official English publications names her "Miss Stake" instead which is still a result from her flubbed introduction but not directly derived like its Japanese counterpart.
- Nice Hat: Wears a Chef's Hat when baking a cake, which Yotsuba praises her for.
- Only Known by Their Nickname: Only her surname Hiwatari is known, but everyone calls her Shimauu/Miss Stake.
- Satellite Character: Satellite to Fuuka. She only appears in a few stories and that's when Fuuka is involved.