Osaka is a 16-year-old transfer student from...Osaka, with shoulder-length straight brown hair and big dark brown eyes. She has a slender build and a relaxed, unassuming appearance. Known for her Kansai hick accent, she often seems slow and absentminded due to her constant daydreaming and tendency to misinterpret things, as well as being a bit of a slow head... Often gets very fascinated by mundane things, such as figuring out how to split chopsticks...sometimes getting irritated when people do it the wrong way.

Tomo Takino is a 16-year-old high school girl with short blackish-brown spiky hair, large dark brown eyes, and fair skin. Energetic and carefree, she acts without thinking about consequences, often irritating her friends—especially Kaza & Koyomi, her best friends since grade school. Competitive and enthusiastic, she proudly gets terrible test scores but genuinely cares for her friends in her own way.

Chiyo-chan is a tiny, adorable 12 year old child prodigy with big orange cone looking pigtails and big brown eyes. Was able to attend highschool due to her genius-level smart yet humble, sweet, and naive, she acts as the group's kind peacemaker while feeling insecure about sports and her height.

Sakaki is a tall 16 year old, athletic high school girl with long, straight black hair and a stoic, quiet appearance that makes her seem emotionless. In conversation, she is shy, non-confrontational, soft-spoken, and incredibly kind. She harbors a deep love for cute animals, especially cats, often hiding her gentle, affectionate behind a "normal" exterior.

Yukari-sensei is a tall, youthful English teacher with back-length brown hair and matching brown eyes. Immature for a teacher and has a short fuse, she swings wildly between tyrannical outbursts and sweet encouragement, acting more like a student than a responsible adult while shamelessly relying on her friend Nyamo-Sensei. She's just as childish and carefree as her students.

Koyomi is a 16 year old with long, straight dark brown hair past her shoulders, oval glasses, and a tall, athletic build . She looks mature and composed. Personality-wise, she's the group's carefree, "all rounder" type—smart, studious, and often a little boastful while also being just as upbeat and energetic. Yet she has insecurities about her weight and can act just as childish at times. Best friend of Kaza & Tomo since grade school.

Tall, athletic 16 year old girl with short dark hair, sharp eyes, and prominent summer tan lines from swimming. A competitive tomboy and star athlete who's energetic, good-natured, and helpful, but also sensitive, easily moved to tears, and a bit airheaded in class.

Nyamo Sensei (Minamo Kurosawa) has long dark hair and an athletic build, often in tracksuit or casual wear. She is a mature, kind, responsible PE and swim coach teacher, popular with students, energetic yet composed, and a sensible rival to the chaotic Yukari Sensei.

Mr. Kimura is a middle-aged classical literature teacher with a gaunt face, short dark/grayish-brown hair, and glasses that permanently obscure his eyes. He is almost always depicted with a slack-jawed, gaping mouth and an eerie, somber aura. Tall and lanky, he wears a formal suit and tie. Known for his creepy, perverted behavior toward high school girls.

Chiyo-chichi is a strange compact, yellow-furred, noodle limbed, vaguely feline form that floats/levitates rather than walking. The father of Chiyo-chan. He levitates, has a fixed open-mouthed expression with unchanging features, and dislikes the color red. Shakes and changes colors when upset; polite yet unsettling, possibly bulletproof.