Nagi Ichinose is an eighteen-year-old senior in high school and a member of the track team, where she is noted for her exceptional running stamina. She is the heir of a powerful yakuza family from Kyoto, giving her a background steeped in tradition and discipline. Despite being biologically female, Nagi adopted a distinctly masculine appearance and demeanor after a painful rejection from her first love, who mistakenly believed she was a boy because of her boyish looks. This rejection caused her to suppress her feminine side and behave in a tough, straightforward manner. Her personality is a blend of outward brusqueness and hidden vulnerability. She is fiercely determined, sometimes to the point of obsession, and can be quite impulsive when pursuing what she wants. Underneath her rough exterior, she is caring and deeply sensitive, especially regarding her past trauma. One of her most notable fears is a phobia of thunder and lightning, stemming from witnessing her grandfather, Jii, being struck by lightning on multiple occasions. Nagi’s primary motivation shifts after she meets Junpei Kousaka. Initially regarding him as a rival, she quickly develops romantic feelings for him after he comforts her during an emotional crisis. From that point, she becomes determined to win his affection, often going to extremes such as transferring into his class even though she had already completed that grade. Her role in the story is that of a supporting character who adds comedic tension and romantic rivalry, particularly with Kaede Mizuno and Kanako Sumiyoshi, who also have feelings for Junpei. Her relationship with Junpei is central to her development: through him, she begins to embrace her more feminine traits and confront her insecurities. Her bond with Kaede is initially antagonistic due to jealousy, but Nagi also shows a softer side when interacting with her cat Josephine, who plays a role in encouraging Nagi to be more open. Over the course of the series, Nagi experiences gradual growth, learning to balance her strong-willed nature with greater emotional honesty. Her notable abilities include her athletic prowess, her perseverance, and her capacity to act decisively under pressure, though her emotional volatility sometimes undermines her plans.