In the beginning of the series, Yoshino is a girl who is very ill and cared for constantly by her grande sœur, Rei. In the second novel, when Yumi was watching Yoshino, Yoshino is described as a girl who is "on the skinny side, but not emaciated—simply that she has a small frame"; her eyelashes are described to be "thick than long"; and that she has an aura (maybe because she is sickly at first) that makes one want to protect her and make her a petite sœur. Yoshino is voted as the best petite sœur near the beginning of the series, as everyone considered her to be soft and sweet; this is only her reputation however. Yoshino is very independent and in some ways tomboyish, despite her sickly status and feminine appearance. After her heart surgery, she becomes more energetic throughout the series, and Yumi begins to see more of her fits of temper (usually directed towards Rei). While Yoshino maintains her "sweet and gentle" image in public, she has apparently grown close and comfortable enough to show her temperamental side to Yumi as well (during their trip to Italy, Yoshino reveals that Yumi is the only one she can comfortably show her weakness to). Yumi also learns that Yoshino is very quick-witted and sharp—Yoshino is able to understand concepts and read between the lines of things so well that Yumi sometimes coins her as a psychic. In addition to being Rei's petite sœur, Yoshino is also her cousin and next-door neighbor. Yoshino admires and loves Rei (and has a knack for throwing tantrums at Rei when she gets jealous or over small issues), however she becomes upset with Rei every time she acts overprotective and fragile.
She has a heart condition that causes her to be frail and weak physically but was then better when she had undergone an operation.
Yoshino was depicted as an epitome of beauty as stated by Yumi. However, she proves her wrong. Despite her femininity, she is actually more boyish than Rei and is independent. Although she shows her sweet and gentle side to the public, she is actually temperamental and easily gets agitated.
She reveals to Yumi that she could only show her true side to her and not to anybody else.
She is quick-witted and sharp. She is known to be a psychic where she could easily read someone's mind easily. Just like Yoshino and Rei does not need words but only needs telepathy or even a just one glance then they already both know what the other is thinking. During the practice of Cinderella, when no one volunteers to be Yumi's partner, just one look from Yoshino to Rei, Rei suddenly volunteers as quietly asked by Yoshino.
She hates Rei for being insensitive to others and for being overprotective with her and fragile. Rei is always making Yoshino to be dependent on her while Yoshino tries to be independent.
In the series, her hobbies were actually boyish that the Newspaper Club had thought that Rei's girly hobbies and Yoshino's boyish ones were completely switched.
She easily gets jealous when it comes to Rei.
Hasekura Rei Edit
Yoshino and Rei are actually cousins and neighbors despite being soeurs. She is also protective and obsessively caring to Yoshino. When her rosary was returned to her, she sulked like her life had just ended. She reveals that without Yoshino, she is weak. Rei also reveals that she thinks of Yoshino in almost everything she does; in her kendo tournament, during her date with Tanuma Chisato, and everything else.
Rei had greatly refused of Yoshino's joining of the kendo club. She said that she's scared that she might get unfair to the others but then might be harsher to Yoshino otherwise. She also said that if she stays in the kendo club, she would only think of Yoshino, worried that she might be hurt or something else. That she can't concentrate with her around.
Even though Rei is her Onee-sama, who has a right to decide her decisions, Rei could never force Yoshino around to do as she was told but the said "order" always turns out to be a "request", as told by Yoshino to Rei.
In the series, it shows that Rei is somewhat powerless to Yoshino.
|“||Bushi no nasake - Have a warrior compassion!||”|
–to Yumi, Season 03, ep. 04