Kouta was your average otaku, living alone in his apartment, surrounded by his figurines and anime body pillows; until Kanau came long. All of a sudden, Kouta has a daughter he never knew existed. Not only that, she is going to live with him, with no support from the mother who suddenly left her in his care. Now Kouta has to learn to be a father, all the while dealing with the rest of the crazy otaku of the Higansou.Otaku no Musume-san(AKA The Otaku's Daughter), is a Shounen, comedy manga that centers primarily around the life of Kouta and Kanau, father and daughter.
This manga provides examples of:
Abusive Parents: The reason Taeko's mother didn't want to take care of her; she thought she would abuse Taeko.
Alpha Bitch: Reika Misono. Her father is a politician and her mother is an actress. However, Reika isn't all that bad and her parents are fairly decent people, even if her mother is a bit snooty.
Anime Hair: Averted, as most of the characters sport normal hairstyles. Played straight with a flashback arc involving Taeko's grandfather, who sports a Heihachi haircut (he says it's James Dean).
Babies Ever After: In an omake at the end of the last chapter Haruka is seen with her young son just learning to walk. The kid's eyebrows give away who the father is immediately. Taeko also has a set of twin girls of her own with Sensei in the last chapter.
Badass: Landlady of all people was this when she turned to delinquency in her early teens. Also her grandfather and at least some of his friends would qualify as this too.
Big Breasts, Big Deal: Taeko is mostly a Type 5 though sometimes she shows signs of Type 3
Big Ol' Eyebrows: Runs in Kouta's family, starting with his mother. Even baby Saori has them.
Can Not Spit It Out: Kouta, in his feelings for Taeko. At least when addressing Taeko directly.
Chekhov's Gun: In chapter 13, Kouta gets Member of Parliament Misono's business card. Forty-nine chapters later, he uses it to help convince Takurou and Nozomi to give Kanau back to him.
Chekhov's Gunman: Nicchi, during Kouta and Nozomi's first time in the art room. He can be spotted in the corner of the panel in Chapter 3, but his presence is either missable or to be assumed as inconsequential. Chapter 58 changes that when we see Nozomi's recollection of the same event, where Nicchi's presence is much more pronounced.
Taeko: Team Mom, more or less literally, as she seems to do most of the cooking for the Higansou
Haruka: The Smart Guy, Smart and snarky, though a bit bullheaded.
Gag Nose: Nicchi's nose, although it wasn't so when he was younger. It grows longer when the worst of his lolicon tendencies begin to show. The second-to-last chapter reveals that the nose is fake.
Genki Girl: Kanau's best friend in school, on top of being an otaku, is constantly energetic.
Genre Savvy: Being an Otaku and all, Kouta (and no doubt the other otakus in the apartment) knows a thing or two about the terminology and such, like how he pointed out Haruka looked like a Tsundere with her Girlish Pigtails after her Important Haircut. Unfortunately, he's blind to the fact that her Tsundere-ness is aimed towards him.
Heroic BSOD: Kouta falls into one after learning Taeko is married, and to Sousuke no less. Nicchi reveals Kouta fell into one for about six months after Kanau's mother up and disappeared almost ten years ago, and came out of it the otaku he is now. Kanau pulls him out after only a few days, this time.
Runs into an even worse one after the Wham Episode (you know, the whole deal with Nozomi never loving him in the first place). To the point where he's represented by a skeleton for the better part of an entire chapter. Then Haruka getsserious. It works.
I Have Boobs, You Must Obey!: Lampshaded at the end of Chapter 49 when Taeko breaks up a fight. Taeko's intentions seem pure enough, but that doesn't stop Kanau from analyzing the situation as such.
Important Haircut: Haruka cuts off her Peek-a-Bangs to emphasise to her elder sister how serious she is about following her own path.
Kissing Discretion Shot: Between Kouta and Haruka, perhaps to represent how her motivations to express her feelings were "tainted," in a sense by Nozomi. The omake in the last chapter and the disappearance of her leggings after the fade to black seem to say a lot more than a kiss occurred in that scene.
When Sousuke begins telling Kouta (both of them are manga artists, mind) about Taeko's history.
Kouta: A story about the landlady from 10 years ago... Sousuke: It's a bit long, but I want you to listen. Kouta: Uh, just how long is it? Sousuke: Hmm. If I only had about 32 pages a month... I'd say four to five months' worth. Kouta: I-I see. That is long... Sousuke: ...yeah. If it was my own work, I'd worry about getting tired of it.
It could also be a reference to how certain Kannagi fans reacted when they learned that one of the characters had an ex-boyfriend, implying she might not be a virgin.
Lolicon: Nicchi is an open and unrepentant lolicon. Played for laughs and Squick value. However, this turns out to be a huge plot point in chapter 58. It's him being a lolicon that lead to the subsequent events of Kanau being born. Nozomi had feelings for him back in high school (and still does), and only used Kouta and Maesawa as ways just to get Nicchi to look at her.
Locked Out of the Loop: Almost everybody at some point, but Kouta all the time. Hilariously though Niichi also seems to be in the know for everything that is going on but just can't be assed to tell anybody.
Especially the fact that Nozomi never loved Kohta at all.
Landlady: Taeko. In the final chapter, she and Sousuke have moved out, so Kouta is the new landlord.
Love Makes You Evil: What Kouta felt, after his first experience. He couldn't forgive himself for taking the purity of Kanau's mother, even though she was the one that jumped him.
Turns out that Kanau's mother jumped him just so she could get Nicchi to look at her.
The mother has returned to take her kids away from their fathers in what could be considered the most Jerkass way possible.
Mistaken for Servant: Taeko gets mistaken for a waitress in an Akihabara Maid Cafe, because on the one hand all waitresses on that day were dressed up in school uniforms (and Taeko was wearing one) and, on the other hand, she looks older than her actual age. A completely reverse case (mistaken for a schoolgirl) happens once to her mother who looks younger than her actual age, and is actually a waitress in a Cosplay Cafe.
Mood Whiplash: Sometimes the transitions are smooth, other times you're jerked from farce to drama.
This is especially true during the Wham Episode. Revealing that the main character's primary love interest is not only married, but has been for three years, to one of his close friends even and then trying to play it off as comedy is a big reason why some fans dislike it.
Nakama: Arguably, the tenants of the Higansou apartments
Kouta to Haruka's crush (and to Nozomi's returned interest in him ten years ago, which led ultimately to the events that kicked off the manga when she finally got sick of his obliviousness).
Subverted: Nozomi never loved Kouta in the first place; she only used him to get her real love interest, Chihiro (Nicchi) to look at her, as she still hasn't given up on him.
Only Sane Man: Considering the residents of the apartment complex, her friends, her own father, and her mother, Kanau comes across as this, at least to herself.
Operation Jealousy: By Nozomi Yukimura. Gone horribly wrong and the cause for the majority of the plot so far.
Parental Abandonment: Taeko's mother, explicitly. Her father isn't present either.
Kanau herself counts, since her mother just sent her off to the father she'd never met to concentrate on work. She's returned, and intend(ed) to take her kids back without being found. She ultimately gets away too.
Parental Favoritism: Haruka is the least favored of her siblings, at least according to her.
Grandparental favoritism also plays a prominent role here, as Mami doesn't want her (and Kouta's) parents to find out that Kanau (and not her own child) is their actual first grandchild.
Pedophile Priest: Nicchi becomes one by the time of the epilogue.
Peek-a-Bangs: Haruka's original hairstyle, which imitated her older sister's.
Porn Stash: To the occasional disgust of Kanau and mortification of Kouta.
Proud to Be a Geek: As expected of the main otaku cast, but Taeko's grandfather really came as a surprise.
Replacement Love Interest: Takurou is this, of a sort, for Nozomi. His slight resemblance to Nicchi (primarily their hairstyles and the shape of their jaw) isn't made obvious until the two meet face-to-face during Kanau's birthday party.
Running Gag: Several. Nicchi's loli tendencies, and his pacification when fed sweets. Kouta's total inability to be badass, even when doing something badass. Kimiko always showing up in cosplay outfits. Also, Nozomi's jobs get increasingly ridiculous.
Slasher Smile: Nozomi in the heartrending antepenultimate panel of chapter 61.
Slice of Life: One of the genres the manga falls under.
Sliding Scale: Kanau hilariously uses one of these to judge Kouta's actions. The scale ranges from pervert to otaku to father to papa.
Social Services Does Not Exist: Averted and played straight. They exist and are referred to in the manga, but they never take an active role in the story. Even when they should.
Tyke Bomb: Nicchi's uncle likes to train the children at his orphanage in various forms of combat. Mostly for his amusement.
Villainous Breakdown: Nozomi in the second-to-last chapter when she and Kouta are arguing over Kanau's custody, to the point where she completely puts down Kouta's (and indirectly her new husband's) otaku habits. Kouta's nonplussed response makes the scene all the more gratifying.
The chapter that reveals that Nozomi never loved Kouta from the start, and her real love interest is Nicchi. To top it off, she's come to take Kanau and Tsukamu away from their fathers, with Nicchi helping her.
Younger than They Look: Taeko. Taken together with Taeko's mother being older than she looks, it makes most people think when they're together that they're friends or siblings.
Or, in one extreme stretch early on, that the roles were reversed and Taeko was the mother of a teenager.