𝘒𝘰𝘺𝘰𝘮𝘪 "𝙔𝙤𝙢𝙞" 𝘔𝘪𝘻𝘶𝘩𝘢𝘳𝘢 — "𝘙𝘦𝘢𝘭𝘭𝘺 𝘩𝘰𝘳𝘳𝘪𝘣𝘭𝘦 𝘥𝘪𝘦𝘵𝘪𝘯𝘨"

Koyomi Mizuhara (水原 暦 Mizuhara Koyomi), better known as Yomi (よみ Yomi). She has long brown hair, Hazel eyes, she's 162 cm tall, 20+ years old, and bears destinguishable glasses.

Yomi is a grade-school friend and general antagonist of Tomo's. She is also the voice of reason, and the most mature and serious of her friends — and as such, the comic foil to the others' silliness. Yomi, if pushed enough by Tomo, will even give her an uppercut that leaves Tomo unconscious on the floor. While Yomi likes to think that she's above her classmates' childish behavior, she can be just as bad as they are. For example, to pass her college entrance exams, she asked Chiyo to infuse an amulet with her intelligence (as Tomo and Osaka had done before). Yomi tends to hide her own childlike sides when around friends, as shown when she pretended that she did not care so much about going to the theme park the first time, but when she was alone, she was more excited than any one of the others and had even bought some guide books. She was also impressed with the first snow of the year once, and had bought a guide book when the gang went to Okinawa which surprised Chiyo-chan because Yomi attempted to have a rather neutral attitude. Yomi also has a rather evil sense of humour, shown when she took part in teasing Osaka when she had the hiccups (after causing them in the first place by deliberately feeding her something too spicy for Osaka to handle). It is suggested that she is much like her physical education teacher, Minamo Kurosawa, much as Tomo is similar to their homeroom teacher, Yukari Tanizaki.

Yomi is both smart and athletic: out of the girls, her grades are second only to Chiyo-chan's, and while she isn't as good as Sakaki or Kagura at sports, she holds her own. Despite appearing healthy and fit, Yomi is dissatisfied with her weight and struggles with her fondness for food, particularly sweets and spicy dishes. She is constantly trying new diets, and sometimes anonymously writes to radio talk hosts for advice or with updates on her progress, which amuses Tomo. Yomi is also a terrible singer, as shown when the girls sing karaoke one Christmas. And for extra, she took a trip to Hokkaido once, and had a huge buffet. Tomo teases her because of this.

Despite the frequent bickering and Yomi's tendency to resort to physical force, such as a well-aimed uppercut, their friendship is an enduring one, mirroring the relationship between their teachers, Yukari and Minamo. Yomi's tolerance for Tomo's antics, though often tested, reveals a deep, if sometimes begrudging, affection. Their constant push-and-pull is a defining aspect of Yomi's character, forcing her into the role of the more responsible, albeit reluctant, guardian.

Despite her mature outward appearance and strong academic record, ranking second in her class only to the genius Chiyo. Yomi is not immune to childish behavior. Occasionally, she drops her composed facade and partakes in the group's silliness, such as her attempt to obtain Chiyo's intelligence via a shrine charm for her own university entrance exams. This reveals a hidden, almost childlike naivete and a desire to take shortcuts. These moments of weakness make her more endearing and prevent her from becoming a one-dimensional "straight man."

In contrast to her high academic performance, Yomi possesses a surprising and humorous flaw: she is a terrible singer. This detail is used for comedic effect, particularly during a karaoke outing with her friends, and showcases another aspect of her imperfect personality. Her enjoyment of karaoke despite her lack of talent further emphasizes that she's not the flawless, uptight character she sometimes tries to project. This, along with other small details like her hatred of cicadas.

Tomo Takino: Tomo has short blackish-brown hair with slightly curled spikes at the ends. She has large, dark brown eyes, and fair skin. Her build is of medium-short height for a Japanese women. Tomo is energetic, hyperactive one. Loud, impulsive, always up to something, always trying to stir the pot or do something "fun" (sometimes at the expense of others' comfort). Very competitive. She tries to challenge others (academically, in sports) often just for the sake of competition. She's not always consistent or disciplined. Tomo is now a policewoman, even plans to join Interpol. Tomo is, however, capable of doing well if she tries — though the only notable instance of this is getting admitted to their prestigious high school, and she only did this to annoy Yomi (as well as actually scoring better than Chiyo at a P.E. test once, for similar reasons). She also likes to irritate Yomi by teasing her about her weight insecurity. Tomo's favourite foods are fried chicken, egg roll, meat-balls and bananas.

Ayumu "Osaka" Kasuga: Osaka has medium-length brown hair, and is now posing as a gym teacher at 20. "Osaka" is her nickname (comes from her being from Osaka). She is kinda spacey, slow to respond, dreamy, often not fully "on top" of things — in a cute, laid-back way. Her humor comes from misunderstandings, her imagination, being lost in her own head, taking things literally, etc. She isn't good with sports or studies (compared to some of the others), but she has her own charm; she's well-liked and accepted. She has a small tongue, and is sensitive to spicy food. She is also really stiff, and uses the Osaka dialect.

Sakaki: Sakaki is a tall, long black-haired, sharp-eyed, attractive and soft spoken girl that feels uncomfortable with her height and busty physique. Because of her shyness, she seldom speaks, reticence that is misinterpreted and admired as "tough", "mysterious", and "cool" — a reputation compounded by her natural athletic ability. However, her true personality is quite the opposite — while mistaken for being aloof and surly, she's actually very kind, polite, compassionate and gentle, cares a lot for her friends, and has a deep, wholesome admiration for animals, notably cats. Sakaki also has a pet Iriomote brown-black striped cat named Maya.

Kagura: Tan skinned, and short-haired tomboy. The sporty, athletic rival to Sakaki. She loves competition, especially in sports. Wants to push herself, often motivated by rivalry. Not as academically strong as some of the others, but tries in her way. More physical, more energetic (though more disciplined in sports. Her relationship with Sakaki is interesting: admiration rivalry respect. She sometimes pushes Sakaki, sometimes is frustrated. While Kagura is driven by competition, she is sweet and sensitive and can be brought to tears, especially when she feels she's let someone down or during emotional situations.

Yukari Tanizaki: A brown long-haired adult. She is not only the girls' English and homeroom teacher (class 3), but a teacher with very unconventional methods and a rather close relationship with the class. Her students are casual enough to call her by her given name (Yukari-sensei in lieu of Tanizaki-sensei, with a few, mostly Tomo, addressing her as the extremely informal Yukari-chan (Japanese); just Yukari in English). Depending on the day, time, and her mood, she can be either a horrible tyrant or one of the sweetest, most touching teachers ever. Her behavior ranges from mercilessly teasing Chiyo and hitting students with blunt objects to kind and gentle words and simple, encouraging notes on tests telling students she believes in them.[citation needed] She is often selfish, irresponsible, miserly, generally dysfunctional, and also easily angered, and shamelessly expects her friend and fellow teacher, Minamo Kurosawa ("Nyamo"), to not only tolerate all of this, but to enable it. Yukari's car, the "Yukari-mobile", Technically, it belongs to Yukari's parents. At one time a nice silver Toyota Corolla, Yukari's reckless driving habits have turned it into a scarred, beaten vehicle. Even the mere mention of the Yukari-mobile can cause terror and flashbacks to anyone who has ridden in her car. Chiyo in particular goes to extraordinary lengths to avoid riding in it or any other vehicle Yukari might possibly be driving. However, Tomo enjoys riding in it.

Minamo "Nyamo" Kurosawa: Adult with black hair, with front hair strands, with shorter hair at the back. Physical education teacher, friend of Yukari from before. More grounded, more composed. She acts as a contrast to Yukari. More mature in behavior; also has her own vulnerabilities. Doesn't always stay serious but generally more responsible. "Nyamo" is a nickname from Kurosawa's student days, but Yukari calls her that, and so does Tomo Takino. Other students call her Kurosawa-sensei, but later on, most of them start calling her Nyamo as well (though they still use the more polite "Nyamo-sensei" instead of Tomo's extremely impolite "Nyamo-chan").