The Nakano Quintuplets live in the 30th floor of a luxurious apartment but later moved to a small, two-story apartment because of their own will. The sisters live with just the five of them. Their mother passed away 5 years prior to the beginning of the main story, and their stepfather lives in a different residence. They were students of Kurobara High School before transferring to Fuutarou's school.
The Nakano Quintuplets have their own unique hand gesture (they make a pinky promise with all five of their hands interlocked together), created their "Quintuplets Finger Game" (guessing which finger a sister show) and Puzzle Game (a game with the sisters' facial features as the puzzle pieces), often do "Quintuplets Jokes" (where they dress and disguise as each other), and tease Fuutarou with a "Quintuplets Game" (where everyone dress like one sister and make someone guess their identity).
Each of the girls' name references a number, indicating the order of their birth. Negi Haruba also associates them with a specific color (as shown in their accessories, outfits, and volume covers).
|Sister||Order||Color||Colored accessories||Personal way to address Fuutarou Uesugi|
|Ichika Nakano||1st (Ichi (一?))||Yellow||Jacket||Fuutarou-kun|
|Nino Nakano||2nd (Ni (二?))||Purple||Ribbon||This Guy / That Guy / You / Uesugi / Fuutarou  / Fuu-kun|
|Miku Nakano||3rd (Mi (三?), alternate reading)||Blue||Jacket||Fuutarou / Fuu-kun|
|Yotsuba Nakano||4th (Yotsu (四?), alternate reading)||Green||Ribbon||Uesugi-san|
|Itsuki Nakano||5th (Itsu (五?), alternate reading)||Red||Jacket||Uesugi-kun|
As shown in Character Introduction Page, the quintuplets have different preferences, as listed below.
|Sister||Liked food||Disliked food||Drink||Snack||Morning Routine||TV Shows||Animal|
|Nino||Pancakes||Pickled things||Room temperature water||Candy apple||
|Miku||Matcha||Chocolate||Green tea||Doll cakes||Checking her fortune||Documentaries||Hedgehog|
|Yotsuba||Mandarins||Green peppers||Carbonated juice||Choco banana||Watering plants around the house||Anime||Camel|
The five sisters of Nakano Quintuplets have large dark-blue eyes, pinkish red/light red hair color, an average height (B88-W50-H159), and a shapely figure. Papa Nakano confirms that the Nakano Quintuplets are "identical quintuplets". Miku states that their physical measurement is the same, and Ichika also confirms that she and Yotsuba have the same figure. Due to their similarities, they can easily impersonate other sister to accomplish various purposes. They can also easily search for the other by asking around.
In the past, the Nakano Quintuplets have very similar looks. All five of them have matching long straight hair and dress lightly with matching outfits. Several years into the future, the young-adults Nakano Quintuplets are shown to be taller and mostly have different hairstyle.
The Nakano Quintuplets are noted to have a beautiful looks. Shimoda comments that Itsuki must be a popular girl. Itsuki herself labels the Nakano Quintuplets as vivacious girls. Ichika also boasts that the sisters are gorgeous. Their classmates praise them as a cutie/beauty and even a random stall owner is impressed by their looks. These features may derived from their mother who is noted to be an incredibly beautiful woman.
While they're physically the same, each sister have different hairstyles and accessories. Due to artistic purpose and better differentiation, the sisters have various shades of red hair color in the manga and anime adaptation (In-Universe, their hair color is the same):
- Ichika: very short hair, light-pink hair color, an earring in her right ear.
- Nino: very long hair (later become short), scarlet hair color, two butterfly-shaped ribbons on both sides of her hair.
- Miku: medium-length hair, brownish hair color, a wireless headphone.
- Yotsuba: short hair, light orange hair color, a green ribbon.
- Itsuki: long hair, reddish orange hair color, two star-shaped hairclips and has an ahoge.
Itsuki, Nino and Ichika wear a handbag, Yotsuba wears a sports bag and Miku wears a ranzel. The sisters usually spends more than twenty thousand yen for their clothes. Yotsuba is shown to wear an animal-themed pajamas  while Ichika is shown wearing night gown. All of the Nakano Quintuplets have the same phone model.
The Nakano Quintuplets follow the "Gotoubun Principles", a philosophy taught by their mother. They consider themselves to be five parts of one whole, and have to share any kind of emotions together, such as anger, joy and love. Their belief to this philosophy is shown several times throughout the series, such as going to the firework festival together, wait the others before celebrating something, and even chose transferring school to stay together as five. The sisters are even willing to give up their luxurious lifestyle and high-class apartment for Fuutarou, believing that they will be fine with anything "as long as the five of them are together".
In the past, the Nakano Quintuplets have very similar behavior. However, due to their mother's death, they started to change. Nino commented that the changes made the sisters grow apart from each other.
- Ichika: developing big sister complex
- Nino: still keeping her hair like her younger self
- Miku: low self esteem
- Yotsuba: sacrifical tendencies 
- Itsuki: obsession to be like her mother
Each Nakano Quintuplets has their own characteristics in dealing with the exams and papers:
- Ichika's sheet is crinkled due to her messiness and writes in cursive.
- Nino would neatly place her sheet in a file.
- Miku's Japanese spelling is good.
- Yotsuba's Kanji is bad.
- Itsuki would use an eraser to get rid of mistakes.
Each of the sisters have different traits and personality, some are similar, and some are contradictory.
- Ichika is mature and playful.
- Nino is aggressive and protective.
- Miku is silent and reserved.
- Yotsuba is cheerful and outgoing.
- Itsuki is serious and earnest.
The Nakano Quintuplets' similarities occurs in many aspects, for example, they all dislike studying  and often made a mess during their sleep. Nino and Itsuki are afraid of needles. They can also be referred as a tsundere. Both Nino and Itsuki also do yoga in the morning. Another similar traits would be Nino and Yotsuba, both have outgoing personality and therefore made a lot of friends.
The Nakano Quintuplets' difference in personality is shown clearly on Nino and Miku. They often fight each other, and is seen as rivals throughout the story. Nino is boisterous and abrasive, while Miku is quiet and soft-spoken.
Another extreme example can be taken from Miku and Yotsuba. Miku is a rather reserved and introverted, while Yotsuba has extroverted personality. Miku is the smartest out of the quintuplets, while the latter is the least intelligent. However, the former is also the least athletic while the latter's athleticism is the highest.
Ichika is a lazy doing home chores, while Nino is hardworking when it comes to minding the house and the only cook in the house. In their love confession, Ichika uses an indirect means to confess while Nino prefer going straightforward and clear.
Ichika labels the Nakano Quintuplets as "idiots". Their academic abilities are very low, and they almost fail their First Year high school. They also generally have low capability of learning. Each one of the sisters have different subjects they excel, but even the grades of those subjects are still mediocre. Despite being a slow learner and having various personal setbacks, they managed to pass the Second Year Final Exams, an improvement from last year's.
Miku states that whatever feat she can achieve, the other four must be able to do it too, since they're Quintuplets. Because of this, Fuutarou believes that the Nakano Quintuplets have the potential to get higher academic scores. Miku's statement imply that the sisters have the same potential, and despite their current abilities, they can be as good as the other (for example Miku can be as good as Nino in cooking or become as athletic as Yotsuba) if they're willing to train. This is later proven when Miku able to produce a good meal.
The sisters each have different specialties, such as acting, cooking, and playing sports. Their strength, like their personalities, are sometimes in contrast or actually complement one another. For example, Yotsuba's athletic skills contradict Miku's physical capabilities, or Itsuki becomes good at reviewing food because Nino is a good cook. One thematic skills the sisters excel is their ability to impersonate the other sister. In Chapter 74, Ichika states that each sister have the other sisters' accessories for quick disguise.
|Sister||Strongest Subject||Known Specialties||Misc.|
|Ichika||Math||Acting||Bad at cleaning.|
|Miku||Social Studies||Better acting skills than Ichika. Bad cook.|
|Yotsuba||Japanese||Athletic||Good at cleaning.|
|Itsuki||Science||A very popular food reviewer.|
Ichika comments that the Nakano Quintuplets used to get along in the past. They used to go to the bath together as five. Yotsuba remembers that Ichika is "the boss of the pack", although Ichika often bullied her. During their childhood, when the Nakano Quintuplets gets sick, their mother always hold their hands. Itsuki notices that the sisters' preference is different from the past. Nino remembers that the sisters used to be the same, but slowly changes in the past 5 years. The current Nakano Quintplets seems distant and not knowing each other's state/situation.
This can be reinforced by the duo Nino-Itsuki and Miku-Ichika that are closer with each other, and seems doing activities together more often than with the other sisters. All five of them are quick to reconcile should they ever at odds with each other.
The sisters love their mother dearly. They follows the Gotoubun Principle passed down from their mother up until now. The Nakano Quintuplets, especially Nino, are eager to watch the fireworks because they used to watch it with their mother. This event is noted to be very important for the sisters. They are hinted to have a bad impression towards their biological father.
To Maruo Nakano, Nino seems to be wary of him. He is the reason why she rejects Fuutarou's presence early in the story. She also dislike how Maruo calls the sisters with "-kun" suffix. Despite the distant daughters, Maruo is tolerant of their antics and even faking holiday tickets so that they can meet their Grandfather.
The sisters, especially Yotsuba, love their maternal grandfather. They were happy whenever they visited him in the past, and willingly dressing up just for his well-being.
Most of the Nakano Quintuplets reject Fuutarou early in the story, due to various reasons, such as pessimistic towards their learning capabilities, being protective, expecting a better tutor, or just because of having a quarrel with him. Over time, due to Fuutarou's hard work, they began to accept and appreciate him one by one. Some even began to develop romantic feelings to him. Itsuki says that Fuutarou already brought a change to the Nakano Quintuplets.
Raiha is acquainted with all of the Nakano Quintuplets, but she is closer with Yotsuba and Itsuki. She plays with Yotsuba during the Fireworks Festival and hang out with Itsuki during the Labor Thanksgiving Day.
Isanari knows all five of them, and seemingly fond of Itsuki. He believes that the sisters will change for the better.
The Nakano Quintuplets are popular in the school mainly because of their beauty. At least three male students already express their adoration to Ichika. Nino has two female friends she usually hang out with. Miku, despite seemingly silent and reserved, has a female friend who calls her Miku-chan (instead of the more formal Nakano-san). Yotsuba has a lot of friends, although most of them are because they needed help. She is the only Nakano Quintuplets who actively participate in various activities, such as helping the Basketball Club, Track Club, helping teachers, and offering to be the Class Representative.
Ebata is Maruo's secretary. He personally took care of the Nakano Quintuplets when they were kids. He has a good relationship with the sisters, and willingly help them for a personal matter.
Itsuki is acquaintanced with Shimoda, her mother's former student. She later work with her for a part-time job.
Nino is working under Manager, and he praises her cooking skill since the first day.
Ichika and 1
- Ichika is the first Nakano Quintuplets whose goals/dreams is shown/stated, which is to become an actress in Chapter 11
- Ichika is the first Nakano whose hand is held properly by Fuutarou.
- Ichika is the first Nakano Quintuplets to "kabedon" Fuutarou.
- Ichika is the first Nakano Quintuplets to be hugged by Fuutarou.
- Ichika is the first who get Fuutarou's contact address.
- Ichika is the first girl who got a proper headpat by Fuutarou (technically, Miku is the first to get a headpat).
- Ichika is the first Nakano Quintuplets who is seen crying in front of Fuutarou. Chapter 27
- Since the bell scene, Ichika is the first Nakano Quintuplets which trigger Fuutarou's awareness towards lips (befitting her name).
- Ichika is the second Nakano Quintuplets Fuutarou sees a half-naked.
- Ichika is the fifth Nakano Quintuplet who directly or indirectly confesses to Fuutarou.
Nino and 2
- Nino is the second Nakano Quintuplets whose goals/dreams is shown/stated, which is to opens a restaurant. Chapter 52
- Nino (technically) fell in love twice with the same person (Kintarou persona and Fuutarou persona).
- Nino is the second Nakano Quintuplets who sees Fuutarou half-naked
- Nino is the second Nakano Quintuplet to give Fuutarou either a direct or indirect kiss to Fuutarou.
- Since the bell scene, Nino is the second Nakano Quintuplet to trigger Fuutarou's awareness towards lips (befitting her name).
- Nino is the second Nakano Quintuplets who is seen crying in front of Fuutarou (Chapter 43)
- Nino is the only Nakano Quintuplets so far who confesses to Fuutarou twice, albeit the first one wasn't heard by him.
- Nino is the first Nakano Quintuplets to be pushed down (although accidentally) by Fuutarou.
- Nino is the first Nakano Quintuplets who is seen half-naked by Fuutarou.
- Nino is the first Nakano Quintuplets who gets his photo taken alongside Fuutarou.
- Nino is the first girl whose ear is touched by Fuutarou.
- Nino is the first girl to slap Fuutarou.
- Nino is the first character to purposely show a middle finger in the series.
- Nino is the first Nakano Quintuplet to change the way she addresses Fuutarou (and also having the highest amount of nickname variations): you, that guy, Fuutarou, and in this chapter, Fuu-kun.
- Nino is the first Nakano Quintuplet to give Fuutarou an air kiss.
- Nino is the first Nakano Quintuplets who rides a bike with Fuutarou.
- Nino is the first Nakano Quintuplets who confesses directly and seriously to Fuutarou.
- Nino is the first Nakano Quintuplets who change the way she addresses Fuutarou (and also having the highest amount of nickname variation): you, that guy, Fuutarou, and later Fuu-kun.
- Nino is the fourth Nakano Quintuplets who directly or indirectly confesses to Fuutarou.
- Miku is the first Nakano Quintuplets to be "recognized" by Fuutarou.
- Miku is the first Nakano Quintuplets to sleep in a bed with Fuutarou.
- Miku is the second Nakano Quintuplets who directly or indirectly confesses to Fuutarou (but Fuutarou thought it was a part of playing home).
- Miku is the second Nakano Quintuplets who hugs Fuutarou.
- Itsuki is the first Nakano to be introduced.
- Itsuki is the first Nakano to get a "Kabedon" from Fuutarou.
- Itsuki is the first Nakano Quintuplet to mention the "First Come, First Served" rule
- 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 girl Fuutarou lean on.
- Itsuki is the first Nakano Quintuplets who hold Fuutarou's hand at the start of the bonfire.
- 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 third Nakano Quintuplets who directly or indirectly confesses to Fuutarou (but she didn't know the meaning).
- Itsuki is the third Nakano Quintuplets whose goals/dreams is shown/stated, which is to become a teacher.
- "If one of you makes a mistake, then overcome it together. If one of you is happy, share it with the others. Joy, sorrow, anger, love..are shared among the five of us..in five equal parts!" - Rena Nakano.
- "If I can do something, of course the other four can too" - Miku Nakano.
- "Fireworks are one of the memories we have with our mom." - Miku Nakano.
- "We will all pass, and make Dad acknowledges Fuutaro" - Nakano Quintuplets 
- The scene where a Nakano Quintuplet accidentally injures their arm by slapping it into a hard surface is a pattern shown several times in the series.