Aoba Tsukishima

Aoba is competitive, blunt and intensely devoted to baseball. She dislikes being treated as less capable because she is a girl and is happiest when she can simply play against strong opponents. Her directness often becomes abrasive, particularly with Kou, whom she has been telling she hates since childhood.

She is also fiercely attached to her family. Her early hostility toward Kou is rooted largely in jealousy over how much time Wakaba spends with him, and that resentment becomes difficult to separate from her later feelings toward him. She rarely communicates emotional vulnerability directly, preferring arguments, challenges and baseball to explicit conversations about what troubles her.

Aoba takes pride in her ability without needing to display everything she can do at every opportunity. She often restrains her pitches because many catchers cannot comfortably handle her full speed, and she judges other players primarily by what they can actually accomplish on the field.

Aoba is an exceptional right-handed pitcher with advanced mechanics, speed, control and baseball awareness from a young age. Her father Seiji Tsukishima plays catch with her from childhood, and the batting center gives her an environment in which baseball is part of everyday life.

Her pitching is good enough to serve as the technical model for Kou's development. Although Kou eventually gains greater raw velocity, Aoba's form and understanding of pitching are already highly developed before he begins competing seriously. She can strike out male players and perform effectively against strong opposition when given the opportunity.

Aoba is not limited to the mound. She can hit, field and play center field, making her a well-rounded baseball player rather than a pitching specialist. Her ability eventually earns her consideration for Japan's women's national baseball team, confirming that her talent is recognized well beyond Seishuu.

Aoba begins as Wakaba's baseball-obsessed younger sister and Kou's persistent antagonist. She already plays organized baseball while Kou appears to be merely a frequent batting-cage customer, making her the obvious athlete of the pair.

After Wakaba's death, Aoba and Kou are left carrying different parts of their relationship with her. Aoba does not initially know the full extent of the dream Wakaba had described for Kou, Akaishi and herself, while Kou quietly begins training to make it possible. Their baseball lives become increasingly intertwined as his hidden pitching ability emerges.

Aoba eventually joins Seishuu's baseball club even though regulations prevent her from playing in official boys' tournament games. She contributes through practice, pitching knowledge and her ability to challenge the players who can take the field. Her talent later brings an opportunity to try out for the women's national team, but an injury prevents her from attending the scheduled trial.

The gap between what Aoba can do and what she is officially allowed to do remains one of the defining practical frustrations of her baseball career. At the same time, watching Kou pursue the mound forces her to evaluate a pitcher whose mechanics originated in her own example. His eventual 160 km/h fastball and Seishuu's qualification for Koshien complete the baseball challenge that has connected them since childhood.

Kou Kitamura is Aoba's neighbor, childhood rival and the person she most consistently claims to dislike. Her resentment begins because Wakaba Tsukishima devotes so much attention to him, but Kou Kitamura becomes the pitcher who studies her form most closely and the person who often understands what she is feeling without being told. Their hostility gradually gives way to mutual romantic feelings, which they finally begin acknowledging near the end of the story.

Wakaba Tsukishima is Aoba's beloved older sister. Aoba's childhood jealousy toward Kou grows directly from how much she wants Wakaba Tsukishima's attention for herself. Losing her sister leaves an emotional wound that Aoba often hides behind pride and hostility.

Ichiyou Tsukishima is Aoba's eldest sister and an observant presence in the household. Ichiyou Tsukishima notices the similarities between Aoba and Kou long before either is comfortable acknowledging how closely matched they are.

Momiji Tsukishima is Aoba's youngest sister. Aoba is protective of Momiji Tsukishima, while their shared home keeps the younger sister close to the baseball-centered lives of Aoba and Kou.

Seiji Tsukishima is Aoba's father and her earliest baseball partner. Playing catch with Seiji Tsukishima helps develop the pitching foundation that later distinguishes her.

Osamu Akaishi knows Aoba from childhood and later plays alongside her in Seishuu's baseball environment. He respects Aoba Tsukishima's ability and understands the importance of her connection to both Kou and Wakaba.

Yuuhei Azuma initially clashes with Aoba's temperament but comes to respect her pitching. [Yuuhei Azuma develops romantic feelings for her, which she does not reciprocate.](#spoiler)

Mizuki Asami is Aoba's cousin and openly expresses romantic interest in her. Mizuki Asami's presence creates additional tension around her relationship with Kou, though Aoba does not treat his interest as the relationship he hopes for.

Akane Takigawa becomes close to Aoba after arriving in the neighborhood. Her striking resemblance to Wakaba initially shocks Aoba, but the two develop a warm relationship of their own rather than Aoba simply treating her as a replacement for her sister.