Reika Miyahara

ᴺᴬᴹᴱ: Reika Miyahara (れいか 宮原)
ᴳᴱᴺᴰᴱᴿ: Female
ᴬᴳᴱ: early 20s
ᴮᴵᴿᵀᴴᴰᴬᵞ: October 9
ᴴᴱᴵᴳᴴᵀ: 171 cm
ᴶᴼᴮ: Patissiere 
ˢᴱˣᵁᴬᴸᴵᵀᵞ: Bisexual
ˢᴵᴳᴺ: Libra
ᵛᴼᴵᶜᴱ ᴬᶜᵀᴿᴱˢˢ: Haruka Tomatsu

ᴸᴵᴷᴱˢ: pastry, dresses, Nyaa-chan, flowers, baking, ribbons, laces

ᴰᴵˢᴸᴵᴷᴱˢ: excessive flirts, spiders, snakes, chores

ᴾᴱᴿˢᴼᴺᴬᴸᴵᵀᵞ: 
Reika is a rather sweet girl with a touch of gentleness and innocence who is sometimes shown to be somewhat passive-aggressive during some idiotic situations. She also has a casual and carefree kind of behavior, as she tends to hit off with her friends with a slightly informal and friendly comportment.

ᴮᴬᶜᴷᴳᴿᴼᵁᴺᴰ: 
Reika never had much troubles in her childhood other than loneliness of being an only child. Among the former jobs her father used to work in, Reika took the most interest in his pastry work. She grew fond of baking cakes, and has recently achieved her dream of owning a pastry shop.

Relationships:
ᶜᴬᴺᴼᴺ ᶜᴴᴬᴿᴬᶜᵀᴱᴿˢ:
• OᔕOᗰᗩTᔕᑌ: At first, Reika wasn't too fond of Osomatsu since he tended to flirt with her often (which she didn't like). It didn't help that he randomly called out her name by accident on a day when they haven't even met yet. However, Reika grew to become fond of his childishness and carefreeness, and ended up falling for him at one point.
• KᗩᖇᗩᗰᗩTᔕᑌ: As nice as he is, Reika always feels uncomfortable whenever he makes a painful remark or anything of the sort. Not really hateful with how painful he is, just... uncomfortable. They are on fairly good terms, though.
• ᑕᕼOᖇOᗰᗩTᔕᑌ: He was the first matsu Reika met, which was sometime after a Nyaa-chan meet-and-greet. They quickly became best friends, in response to the way their personalities and Nyaa-chan obsessions clicked together.
• IᑕᕼIᗰᗩTᔕᑌ: Due to his distant behavior, Reika and Ichimatsu have not talked to each other often. However, they are still on pretty ok terms, as Reika sometimes talk to Ichimatsu and gives him some sardines and fish crackers.
• ᒍYᑌᔕᕼIᗰᗩTᔕᑌ: Reika and Jyushimatsu's relationship is a pretty cute friendship you'd probably expect from the two of them. Other than those times Jyushimatsu frightens Reika a bit by abusing a person or two (which is usually Ichimatsu).
• TOᗪOᗰᗩTᔕᑌ: Reika finds his girliness and surprisingly not-so-high fashion sense a bit strange, but she gets along well with Todomatsu.
• TOTOKO: Reika haven't really met her, but has seen her before. She does admit that Totoko is cute.
• ᗪEKᗩᑭᗩᑎ: As much as how good and reliable of a scientist Reika acknowledges Dekapan to be, she finds him odd to take care of dog "children" that she had to unfortunately babysit before.

ᴼᶜˢ:
• ᗰIᔕᗩKI KOTEGᗩᗯᗩ: Reika and Misaki are casual friends. They've known each other for a year now.

ᵀᴿᴵᵛᴵᴬ:
-Reika has been a Nyaa-chan fan for at least 2 years now.
-Reika has a complex of wanting to always be pretty, but it's not that extreme.
-While she's not really a fan of children, Reika does enjoy reading to them.
-Reika was in line when Osomatsu ruined Choromatsu's meet-and-greet time with Nyaa-chan.
-Despite her surname, which means "plain of the shrine," she's not religious (but her father is)
-She's not yet aware she's a cm taller than the matsus

Misaki Kotegawa

ᴺᴬᴹᴱ: Misaki Kotegawa (美咲 古手川)
ᴳᴱᴺᴰᴱᴿ: Male
ᴬᴳᴱ: 20s (a bit older than the Matsus)
ᴮᴵᴿᵀᴴᴰᴬᵀ: April 12
ᴴᴱᴵᴳᴴᴿ: 175 cm
ᴶᴼᴮ: jobless
ˢᴱˣᵁᴬᴸᴵᵀᵞ: Bisexual (but more towards the homo side)
ᶻᴼᴰᴵᴬᶜ ˢᴵᴳᴺ: Aries
ᵛᴼᴵᶜᴱ ᴬᶜᵀᴼᴿ: Nobuhiko Okamoto

ᴸᴵᴷᴱˢ: casual reading, video games, jokes

ᴰᴵˢᴸᴵᴷᴱˢ: his brother, drama, burnt food

ᴾᴱᴿˢᴼᴺᴬᴸᴵᵀᵞ:
Misaki is relatively an easygoing person. While somewhat polite and humble-seeming (not to his friends, father, and brother, tho), he can be rather air-headed and silly. He's also pretty mentally stupid.

ᴮᴬᶜᴷᴳᴿᴼᵁᴺᴰ:
Misaki lived under a strict mother and easy father with his younger brother, Akio. Misaki was rather playful when he was younger (still is, but significantly not as much) and played a bit with his brother until late elementary school, when he began to become attracted to books. This new hobby of Misaki's led to him slowly drifting away from society, until it came to the point where he became an introvert Akio hated. Since then, the brothers' relationship became one full of easily-provoked bickering, and eventually simmering down to quiet but obvious animosity.

As for how Misaki met the Matsu brothers, it's still a mystery.

Relationships:
ᶠᴬᴹᴵᴸᵞ:
• ᗪᗩIᔕᑌKE KOTEGᗩᗯᗩ: Cheerful father. Misaki does love him, and tends to sometimes count on him for his personal problems. His father gets along better with Akio, though, and it felt risky to bond with him anyway (since Misaki could accidentally reveal he was partially homosexual, and his father's a homophobe).
• ᗩYᗩKᗩ TᗩᑎᗩKᗩ: Austere mother. Misaki loves her, but not much. This is due to her merciless-like behavior and tendency to scoff rather than praise. She can be nice and sweet, but generally, she's not a woman Misaki likes to bother very much.
• ᗩKIO KOTEGᗩᗯᗩ: The brother Misaki hates. Just as how Akio hates him for his introversion and blandness, Misaki hates Akio for his childishness and arrogance.

ᶜᴬᴺᴼᴺ ᶜᴴᴬᴿᴬᶜᵀᴱᴿˢ:
• ᗰᗩTᔕᑌᑎO ᗷᖇOTᕼEᖇᔕ: Misaki is on good terms with them and pays them a cheerful monthly visit (later turning to twice a month). While he spends time with each of them as good friends, Misaki has a (large) love interest for Karamatsu and favors him the most. However, he doesn't show it much, due to his talent in hiding emotions.
• TOTOKO: Misaki met her while hanging out with the Matsus at the horse races, as she was someone the brothers invited to tag along with them. While he does find Totoko cute, Misaki finds her rather despicable (though he doesn't hate her).
• ᑕᕼIᗷITᗩ: It was once again due to the Matsuno brothers that Misaki got to meet this short dork. Comforted by Chibita's delicious oden, Misaki goes to the short man's oden shop every now and then to treat himself.
• TᕼE OTᕼEᖇᔕ: Similar relationships. Misaki just never met Hatabou, Dayon, or any one-time characters.

ᴼᶜˢ:
• ᖇEIKᗩ ᗰIYᗩᕼᗩᖇᗩ: Reika and Misaki are casual friends. They've known each other for a year now.

ᵀᴿᴵᵛᴵᴬ:
-Misaki is a pretty good liar due to the four years he participated in drama club (7th-10th grade) during his school years.
-Misaki never met the Matsuno brothers during his childhood, even though Karamatsu was in the same drama club as him when Misaki was younger.
-His mother liked the idea of giving him a girly name, thus living by the name "Misaki."
-Sometimes, Misaki likes to play pranks on his friends, especially with Osomatsu and Jyushimatsu. He only plays or joins in to lighter ones, though.
-Despite reading plenty of books, Misaki didn't really make good grades in school. Probably because he mostly read picture books.
-Initially, Misaki disliked Osomatsu as well due to his similar nature to Akio's. It didn't take long, however, for Misaki to like Osomatsu and appreciate his quite different and dorky personality.
-He was originally designed with blue eyes.

Marumatsu Matsuno

ᴺᴬᴹᴱ: Marumatsu Matsuno (丸松 松野)
ᴳᴱᴺᴰᴱᴿ: Male
ᴬᴳᴱ: early 20s
ᴮᴵᴿᵀᴴᴰᴬᵞ: May 24
ᴴᴱᴵᴳᴴᵀ: 170 cm
ᴶᴼᴮ: NEET
ˢᴱˣᵁᴬᴸᴵᵀᵞ: Heterosexual
ᶻᴼᴰᴵᴬᶜ ˢᴵᴳᴺ Gemini
ᵛᴼᴵᶜᴱ ᴬᶜᵀᴼᴿ: Natsuki Hanae

ᴸᴵᴷᴱˢ: music, girls, games, sororities, beer, pears, oden, hamjuku, porn

ᴰᴵˢᴸᴵᴷᴱˢ: Karamatsu's dick, cold-ass water, couples

ᴾᴱᴿˢᴼᴺᴬᴸᴵᵀᵞ:
Marumatsu is a cheerful and somewhat conceited young man who has an obsession over music - especially if it's heavy metal and/or rock music. While he can be slightly arrogant, obnoxious, and nosy, Marumatsu is generally just a mostly-self-concerned NEET who simply likes having a good time - thus valuing fun over work. Along with the title of "second most energetic brother," Marumatsu is known as the "second most popular with girls" (not that he and Totty are all that popular with them anyway) due to his ability to socialize rather well with a calm and mature persona.

ᴮᴬᶜᴷᴳᴿᴼᵁᴺᴰ:
As a kid, Marumatsu tended to be unafraid to voice his opinions and often got into arguments due to that. However, the discourse he sometimes tended to cause usually never bothered him, as he liked to fight. Marumatsu was also rather laid-back, and never really caused mischief unless he wanted to. In situations when the brothers split into pairs, Marumatsu often went alone, or with Karamatsu and Todomatsu if he could.

Relationships:
ᶜᴬᴺᴼᴺ ᶜᴴᴬᴿᴬᶜᵀᴱᴿˢ:
• OᔕOᗰᗩTᔕᑌ: Marumatsu honestly don't mind Osomatsu being his oldest brother. They get along pretty well, considering their similarly cheerful and easygoing personalities.
• KᗩᖇᗩᗰᗩTᔕᑌ: Despite the amount of cringe and pain Marumatsu often feels with Karamatsu's excessively narcissistic + poetic manner, Marumatsu actually gets along with Karamatsu rather well.
• ᑕᕼOᖇOᗰᗩTᔕᑌ: While Marumatsu doesn't hate Choromatsu, he isn't sure of how much he likes him. He doesn't really understand why Choromatsu makes such a fuss over them getting jobs, especially since he's such a hyprocite (and a weird one on top of that), but Marumatsu honestly doesn't mind him at all.
• IᑕᕼIᗰᗩTᔕᑌ: Like his other brothers, Marumatsu never really saw Ichimatsu as the kind of person you could really approach until when Ichimatsu's lack of social skills and faith in himself was revealed. Since then, Marumatsu came to appreciate Ichimatsu a little more, though he's still conscious of Ichimatsu's dark and menacing aura.
• ᒍYᑌᔕᕼIᗰᗩTᔕᑌ: With his fellow optimistic brother, Marumatsu and Jyushimatsu often go all out whenever playing with each other. Marumatsu finds a lot of fun in playing with Jyushimatsu, and is usually never bothered with what Jyushimatsu does.
• TOᗪOᗰᗩTᔕᑌ: Past his annoyed impression on the pink satan's cold-heartedness and tendency to bash on his brothers sometimes, Marumatsu does mentally admit Todomatsu is kinda cute. Since they also happen to be rather close and the only two brothers of the household who actually have some sort of social status, they at least could share their troubles with each other and try hanging out with girls sometimes.
• TOTOKO: Like his other brothers, Marumatsu is heads-over-heels in love with Totoko. He believes Totoko is very very cute, though deep deep inside, he's aware of his extremely low probability in dating her - much less being appreciated as a true friend.
• IYᗩᗰI: Marumatsu doesn't really think much of Iyami at all (he even looks down at him sometimes), but he does love teasing him. It's rare, however, that you'd see Marumatsu teasing Iyami alone, since he prefers to tease Iyami with at least one of his brothers and doesn't find too much of a significant hobby out of it.
• ᑕᕼIᗷITᗩ: While the two haven't individually talked to each other much at all, Marumatsu enjoys Chibita's oden. Chibita's oden is basically Maru's favorite kind of oden, so he really likes coming over. That is to say, Marumatsu never pays.
• ᗪEKᗩᑭᗩᑎ: Aside from Dekapan's eccentric character, Marumatsu certainly trusts Dekapn's intelligence and reliability, despite the strange circumstances that always come with Dekapan's inventions. He especially likes how it was thanks to Dekapan that he even got to know anything more about Ichimatsu now.
• ᗪᗩYOᑎ: While Marumatsu and Dayon have barely exchanged a word to each other before at all, if at all, Marumatsu often found annoyance in the times whenever Dayon transported him to another place with his sucking mouth. He doesn't say anything about it, however, since they rarely get a chance to talk anyway (not that they even talk), and being transported by the mouth makes it too late already. Dayon is also a mystery Maru doesn't really bother to think about.

ᵀᴿᵛᴵᴬ:
-Marumatsu's name comes from the word "maru," which means "circle." This refers to his somewhat restless and cheerful personality.
-He can be considered to be between Osomatsu and Jyushimatsu when it comes to cheerfulness and energeticness.
-He's the sixth brother, leaving Todomatsu as the last (due to the spoiled personality Totty was stated on gaining from his youngest status & the phrase "todo no tsumari" ["in the end"] that Todomatsu uses & whose name was probably based on as well)

(I'll update the others later)