Miku Nakano

Miku is presumably bisexual but is more attracted to men than women, unless the woman is beautiful enough.

Miku Nakano was the first of the quintuplets to open her heart to Fuutarou Uesugi. Attracted by his intelligence and determination, she, a shy and reserved girl, found in him a reason to step out of her comfort zone. Thanks to Fuutarou, Miku began to value herself more, express her passions—such as her love of Japanese history—and dare to openly compete for his affections.

Throughout the story, Miku becomes one of the most consistent in expressing her feelings: she cooks for him, supports him, indirectly confesses her feelings, and even confronts her sisters so as not to lose him. However, although Fuutarou deeply appreciates her sincerity and tenderness, his feelings eventually lean toward another of the quintuplets.
The main reason Miku wasn't the chosen one lies in Fuutarou's vision: he wasn't just looking for a girl who admired him, but one with whom he shared a deeper bond, a connection that went beyond obvious affection. In that regard, Miku, despite her efforts, never managed to fully align her feelings with his.
For Miku, that outcome was painful, but it also solidified her as a stronger person, capable of loving without regret. Her courage and personal growth were not in vain: although she didn't win back Fuutarou, she gained something equally important: self-confidence and the respect of her sisters.

According to Yotsuba, Miku is the most intelligent of the sisters, and her strongest subject is social studies. She has an extensive knowledge of Japanese history. Miku is also shown to be able to perfectly mimic her sisters' appearance and personality without others recognizing her.

Miku has low physical abilities (probably the lowest of the five) and is poor at cooking. She is also less able to understand the reasoning behind human relationships, implying a lack of romantic knowledge.

Miku is a quiet and reserved girl with a pessimistic mindset and low self-confidence, even to the point of self-deprecation. Fuutarou points out that Miku lacks faith in herself. Contrary to her reserved self, she can speak directly and doesn't hesitate to confront others.

Miku has an obsession with the generals of the Sengoku period. She is greatly influenced by their philosophies, to the point of affecting her behavior in real life. Miku hides this fact from everyone and is embarrassed when Fuutarou finds out.

Among the Sengoku generals, Miku likes Takeda Shingen the most. This is hinted at many times throughout the series. She sets Takeda's logo as her phone's wallpaper. She often quotes verses from Fūrinkazan, which was the war flag used by Takeda Shingen. When Fuutarou challenged Miku to a duel of historical knowledge, Miku is portrayed wearing armor identical to Takeda Shingen's.

Despite her slightly negative outlook on life, such as when Miku asks Fuutarou to abandon her, she is the first sister to abide by the Go-toubun Principle. Miku always reminds herself to follow this principle, even compromising her own interests to ensure everyone is treated equally.

According to Fuutarou, each Nakano quintuplet has their own characteristics regarding their leaves. In Miku's case, she has good handwriting.

Miku is a generally emotionless girl with medium-length auburn hair with strands hanging over the right side of her face (ranging from light pink to antique pink in Volume 1, and pearl pink to beige brown in Volume 4). Her notable accessory is a set of wireless headphones with a triangle-shaped Audio-Technica logo on the earpieces. Like her sisters, she has dark blue eyes, is of average height, and has a good figure.

Miku usually wears a long-sleeved sweater that covers her uniform. She also wears black tights and places the headphones around her neck. Most of the time, she has part of her bangs covering her right eye. Miku has a Japanese-themed room.

It's clear that Miku has little sense of modesty and cares less about her appearance.

In the five-year time jump, Miku radically changes her appearance, dropping her headphones and sporting long, straight hair, having changed her hairstyle to include bangs divided into two long, thick strands arranged parallel to each other, exposing her forehead.

She is the third sister of the Nakano quintuplets. Due to Fuutarou's influence, she is the first of the sisters to befriend him.