Shinji Kido: 5 years old, middle class. Boy. Usually with Ren. First person: I (casual/rough). Clumsy but has a sense of justice twice as strong as others; a natural do-gooder who can't help sticking his nose into everything.

Ren Akiyama: 5 years old, middle class. First person: I (casual/rough). Boy. Friends with Shinji but can't be honest about it. His personality is the opposite of Shinji's—cool and cynical. Furthermore, because he is stubborn and quick to fight, he has easily made enemies since long ago and tends to be isolated from those around him.

Miyuki Tezuka: 5 years old, senior class. First person: I (casual/rough). Black hair, calm. Usually with Shinji and Ren. Sometimes hangs out with Jun. Loves fortune-telling using coins. Catchphrase: "My predictions always come true."

Yui Kanzaki: Homeroom teacher for Atori Class. Shiro's younger sister. A teacher loved by everyone. Everyone calls her Yui-sensei. A strong-willed, reliable person, but sometimes shows a rough, careless, or scatterbrained side.

Shiro Kanzaki: Director of the nursery school. Always expressionless and gives off a somewhat lifeless atmosphere, but occasionally wears an evil smile (which makes the kids afraid of him). However, he is actually kind, patting heads and occasionally giving out stickers.

Shuichi Kitaoka: 5 years old, senior class. Brown hair parted in the middle. Weak body but strong heart; dreams of being a super lawyer. He prioritizes having fun and doesn't participate in active mischief, but he secretly watches from above. Dry personality but actually kind. He is very troubled by Takeshi chasing him around. "I'm like... (boasting)" "Goro-chan!"

Takeshi Asakura: 5 years old, senior class. Blonde, fluffy hair. First person: I (casual/rough). Loves playing war. Often tries to sneak out. Stalking Shuichi. Catchphrase: "It's irritating me..." "Kitaoka, play with me." Often bullies Shinji and Ren. A problem child. Often tries to eat grass, sand, and eventually lizards; a child who doesn't know how to interact with friends.

Masashi Sudo: 5 years old, senior class. Black hair parted in the middle. Has a crab keychain; dreams of being a detective. First person: I (polite) / Second person: you (polite). Acts like a teacher's pet, but does bad things behind their backs. Vents his frustration on objects when irritated.

Goro Yura: Homeroom teacher for Kagami Class. Everyone calls him Goro-chan. Due to his taciturn attitude, he seems unapproachable and eerie at first glance, but in reality, he is sincere, kind-hearted, a great cook, and strong. Liked by Shuichi.

Reiko Momoi: Assistant teacher for Kagami Class. A stout-hearted woman with a strong sense of responsibility. Good at teaching. Often receives advances from Shuichi. Usually has sweets. Takes photos of everyone with a camera.

Hajime Nakamura: 5 years old, middle class. Black, silky hair. First person: I (casual/rough). Extremely loyal to Kagawa and has a short temper. At odds with Shinji. Clings to Kagawa-sensei.

Satoru Tojo: 5 years old, middle class. Black, fluffy hair. First person: I (soft/polite). Acts like a good boy in front of teachers. Often clings to Kagawa-sensei, quietly following behind him. "...maybe." "...might be the case." Often with Mitsuru.

Mitsuru Sano: 5 years old, middle class. Brown hair, squishy cheeks. First person: I (casual/rough). A mood-maker who is good at flattery; a sycophant. Loves money, but kind to friends. Often carries a deer plushie. First person: I (casual/rough) / Second person: you (soft) / Senior / You (polite/distant). Often with Satoru.

Jun Shibaura: 5 years old, middle class. Short black hair, cheeky. First person: I (casual/rough). Loves games. Because he's rich, he's a bit mean and prideful, but gets a little angry if treated kindly. Often with Miyuki. On bad terms with Shuichi. Afraid of Takeshi. Calls everyone by their names without honorifics.

Hideyuki Kagawa: Homeroom teacher for Walrus Class. Wears glasses. On bad terms with Shiro. First person: I (polite). A genius with photographic memory who rarely shows emotion, but possesses a strong sense of justice. Has a lot of affection and loves all his students. Speaks somewhat politely. "It is ..., isn't it?" "It's ..., Master [Name]."