|“||Your very existence has already begun to stir a change in the five of us.||”|
—Itsuki Nakano to Fuutarou
Itsuki Nakano (
Itsuki reveals to her sisters' that she wants to be a school teacher in which everyone supported her decision.
Appearance EditItsuki is a serious looking girl with medium-length hair and expressive ahoge. She has reddish-orange hair color, ranging from light pink to salmon pink in Volume 1, and deep orange to orient red in Volume 4. Her notable accessories is a pair of star-shaped hairpins. near both of her eyes. Like her sisters, she has dark blue eyes, an average height, and well-endowed figure.
Fuutarou calls Itsuki's hairpins as unfashionable.
Itsuki is noted to be "cute" by her classmates. Itsuki wears glasses in class. According to Shimoda, Itsuki looks very similar to her mother. Itsuki wears her uniform normally without any accessory, like most of the girl students. Itsuki wears a handbag. Itsuki's ahoge changes form depending on her expression. Itsuki's ahoge is retractable. Itsuki's ahoge changes when she's shocked. She is the sister with the highest weight, yet refuse to acknowledge it. Itsuki is the only sister known to wear glasses.
Itsuki is a serious and earnest girl. She usually wakes up early compared to other sisters. Her speech is formal and polite. She cares about mannerism and doesn't hesitate to confront a stranger about it, though it's probably only about table manner.
Itsuki is a girl who bears a grudge. She rejects Fuutarou's tutoring partly because of their previous quarrel. She is also someone who can't be honest with herself and having difficulty to be more straightforward. Both of these qualities often made her struggle on her own.
Itsuki cares a lot about eating manner. Itsuki has never been late and missed a class. Nino comments that Itsuki is too straight-laced. Itsuki is too precise in her timing during cooking.
Nino is more interested in a romance movie while Itsuki prefer Science documentary.
According to Fuutarou, each Nakano Quintuplets has their own characteristics regarding their sheets. On Itsuki's case, she would use eraser instead of scribble on them.
Itsuki is a crybaby, be it about unfavorable situations, scary things, or her stubborn self. Earlier, Itsuki is left alone and is on the verge of tears. This is a hint of her crybaby traits. During the Test of Courage, Itsuki is seen crying looking for Nino. Itsuki has a huge appetite and is mostly seen eating something throughout the series. It appears that she doesn't mind treating her sisters unfairly when it comes to food-related stuff. Itsuki proposes to share their cakes, and Ichika suspects her real goal is to sample all of the flavors. Itsuki worries about Fuutarou, but it actually because she's hungry.
According to Ichika, Fuutarou have to be firm to deal with Nino and be kind to deal with Itsuki.
Itsuki is commended as a diligent girl, and she does thing very precisely. She is also perceptive and has a good sense of detail. Despite that, she has an awful sense of direction. She also has poor eyesight and often seen wearing glasses. Itsuki has good observation and deduction skills. Among the sister, Itsuki is ranked on the higher part of the five, with her strongest subject is Science.
Itsuki never realizes Miku's affection towards Fuutarou, and she is the last sister to know about it.
- "In the end, we can't know what he feels, what he thinks, unless we ask him personally" - Itsuki Nakano.
- "Aren't you going to set a good example? We're counting on you" - Itsuki Nakano.
- "How does it feel to receive words of gratitude from someone you taught? For me.. I want to treasure the feelings from that time" - Itsuki Nakano
- "The numerous days we spent studying for exams, fireworks festival, field trip, new year celebration, we spent all that time together. Doesn't that already make us... friends?" - Itsuki Nakano 
- Itsuki is attributed the "first girl" of the series.
- Itsuki is seen wearing glasses when she's about to do the test (Chapter 2), suggesting she has hyperopia (far-sightedness). In Chapter 3 with Fuutarou, he remarks that Itsuki can't see far away, suggesting she has myopia (near-sightedness).
- Itsuki believes in fate and charms.
- Itsuki's notable accessory is two stars on the front of her hair, representing number 5, which is a part of her name and the order of her birth.
- Itsuki won 3rd place on Japanese popularity poll with 1235 votes.
- Itsuki's food critic pseudonym, May (M·A·Y?) literally means May in English, as in the fifth month of the year. Itsuki (五月?) is also May in Japanese.
- Itsuki is the second Nakano Quintuplet who gets her picture taken alongside Fuutarou. However, she is the first Nakano Quintuplet who took a picture with Fuutarou properly.
- Itsuki is the first Nakano Quintuplets who receive a "kabedon" from Fuutarou in Chapter 1.
- Itsuki is the first Nakano Quintuplets who is seen crying. She had been implied to cry at the Fireworks Festival Arc.
- Itsuki is the first Nakano Quintuplets who hold Fuutarou's hand at the start of the bonfire.
- Itsuki is the third Nakano Quintuplets who directly or indirectly confesses to Fuutarou.
- Itsuki is the third Nakano Quintuplets to be seen half-naked by Fuutarou, the first is Nino (Chapter 5) and then Ichika (Chapter 35).
- The name "MAY" that Itsuki uses means the fifth month of the calendar, while Itsuki's name literally means the month of May in Japanese.