Takuya EnokiA kind but rather naive 5th grader who is overworked.
- Babies Make Everything Better: Yukako's pregnancy with him is what really brought her and Harumi together.
- Promoted to Parent: A lot of the drama in the series is centered around this. Since their mom died in car accident, Takuya had to become mom to his little brother, who's two
- Tragic Keepsake: A baby picture of himself with his mother. When Minoru draws on it with a crayon, he's in tears and, while his dad tries to calm him down, he shoots back that the picture was their only one they had of their mother with him as a baby
Minoru EnokiA rather gullible self-absorbed toddler who really looks up to his big brother
- Adult Fear: The most upset we've ever seen Harumi and Takuya up in the whole series is when he gets hit by a car and almost dies.
- Annoying Younger Sibling: Played for drama. He doesn't mean to be but caring for him does take up Takuya's time.
- Baby Talk: He's two, so he talks in this naturally (like pronouncing "puppy" as "pubby" or his catchphrase of "Bwaza!")
- Big Brother Worship: As much as he annoys his brother, he really loves and looks up to Takuya.
- Childhood Marriage Promise: Subverted and played for laughs. Minoru will agree to marry anyone who asks him. He has no idea what the meaning of Minoru, will you marry me? is. To be sure, Minoru is by no means among the brighter characters in the series and he seems to be slightly less intelligent even by toddler standards.
- Death of a Child: Narrowly Averted. When he's struck by a car, he's mortally injured but thankfully doesn't die.
- It's All About Me: Being two, he demands a lot of attention and care, on top of not knowing any better.
- No Infantile Amnesia: Played with. He doesn't remember his mother too well because he's two, however, he does feel her absence.
Harumi InokiTakuya and Minoru's dad. He's often away at work, leaving most of the latter's care to Takuya
- Gender-Blender Name: His name is usually used for girls.
- When You Coming Home, Dad?: The most we see him is when he's not at work. His being at work most of the time is why Takuya's in charge of Minoru.
Yukako EnokiTakuya and Minoru's mom. She died in a car accident by the story's start
- Adult Fear: The story arc about her and Harumi meeting deals with all sorts of struggles that adults deal with or at least think about. From Yukako feeling the need to move in with Harumi due to her own home not being safe to unplanned pregnancy, among other things.
- Babies Make Everything Better: What really brought her and husband together was her pregancy with Takuya
- But I Can't Be Pregnant!: Her initial reaction to finding out she was pregnant with Takuya.
- Does Not Like Men: She once felt this way, due to a belief that All Men Are Perverts. She does have reason for believing such; someone HAD been taking nude photos of her, and the only person she could turn to for help once asked her for a one-night stand, although she did eventually realize not all men were that way.
- How Dad Met Mom: The entire story arc with her backstory is dedicated to this, starting with Harumi meeting her in a bento shop.
- Missing Mom: She passed away in a car accident.
- Parental Abandonment: She was raised by other relatives after her parents died in an accident when she was 10
- Plot-Triggering Death: Her death forces Takuya to take on a more parental role to Minoru, which in turn leads to a lot of the drama in the series.
- Shotgun Wedding: She and Harumi got married not long after finding out she was pregnant.
Akemi FujiiThe oldest daughter who's usually left in charge of her siblings and looking after the house when her parents are at work
- Promoted to Parent: Downplayed. Unlike Takuya, neither of her parents are dead but, like Harumi, they're just busy, so she's left in charge.
- Vague Age: She's the oldest of the Fujii kids but her age isn't mentioned, however, we get a clue she's probably 18 or 19, if not 20-years old, since Tomoya is 17
Tomoya FujiiAkemi's 17-year old brother
- All Men Are Perverts: Maybe not all of them but he's pretty dirty-minded and immature
Asako FujiiAkemi's 15 year old sister. She a little cold and distant, also jealous of Takuya being cheerful. She has a crush of Sakamaki
- Perpetual Frowner: She looks sullen all the time.
- Unknown Rival: To Takuya. She's jealous of him being so cheerful for some reason.
Akihiro FujiiTakuya's classmate, who's the fourth kid in the family. He's intelligent, competitive, and good looking
- The Ace: He's considered as this to his classmates, who think of him as "cool" because no one can seem to sort out what he's thinking
Ichiko FujiiThe youngest sister of the family, who has a crush on Minoru.
- Ironic Name: Her name would suggest she's the first daughter, when she's really the fifth kid
- The Rival: She sees Hiro as this, specifically, she sees him as a rival for Minoru's attention
Masaki "Ma-Bo" FujiiThe youngest brother, who's younger than Minoru.
- Brainy Baby: Downplayed. He's younger than Minoru but he has more of a vocabulary than the latter does
- Good Is Dumb: He's one of the nicest kids, however, him being so nice makes it easier for Ichiko to pick on him
- Vague Age: He's younger than Minoru (who's two at the start of the manga and turns three later on) but, since he can walk and talk, he's probably not that much younger.
Tadashi "Gon" GotohA classmate of Takuya's who likes to dance. His older sister is Hiroko Gotoh.
- Foil: He's a complete opposite to Takuya, who's loving and caring towards his brother, along with being hard-working and diligent, while Gon's lazy and can't really be bothered with his sister
Hiroko "Hiro" GotohGon's little sister who's about Minoru's age. She has the same face as Gon
- Tomboyish Name: Her nickname "Hiro" is usually used as a boy's name
- Lady Looks Like a Dude: She was once mistaken as a boy.
- Strong Family Resemblance: She has the same face as Gon
- Tomboy: She plays roughly and she doesn't look girly in the slightest
Tokio TamadateA rich classmate of Takuya and Gon's, who wears designer clothes and gets into fights with Gon and picks on Takuya
- Rich Bitch: He's rich and he's really stuck up.