Hikari is the protagonist of the story. She holds the 2nd position in school for having the best grades. Self-proclaimed as Kei Takishima's greatest rival, she is determined to beat him in any kind of competition. Stubborn, proud, hard headed, kind, and good-spirited, Hikari never backs down from a challenge, especially one from Kei, and cannot turn away from someone who asks for her help. Though she has never beaten Kei at anything, she constantly looks for opportunities to surpass him and is generally unfazed when he defeats her. While she is good at sports and academics, Hikari is notably very bad at teaching and cooking. She is too strong at times, even breaking things in the process. Although she can handle her own in a fight (often against boys), Kei, nonetheless, gets irritated whenever she puts herself in danger.
A kindhearted girl who always worries about others, Hikari sometimes lacks common sense and tends to be unaware towards how people regard her. Her optimistic personality, straightforwardness, and tendency to always see the good in people sometimes prevents her from realizing the more subtle aspects of relationships. Although Hikari is rather sensitive to others, she is quite dense when it comes to love. She is oblivious to the romantic feelings Kei has for her, though everyone else knows that Kei is in love with her. In volume four, Hikari begins to fall in love with Kei, though she does not realize it until volume 6. Hikari felt that if she conveyed her feelings she would lose against Kei, believing that it is all a competition. They eventually admit they are in love with each other and become a couple in chapter 53.
