A third year student of Fujigaya introduced at an unspecific chronology. She is about to graduate yet spends all her time following Yamashina-sensei around the campus. She boldly says that she loves Hinako and does not give up her romantic advances despite Hinako's rejection. Kawakubo seems pleased that Yamashina-sensei turns her down because they are teacher and student rather than because they are two women. She spends a lot of her time in the science lab with Yamashina and there she confides in her teacher. She reveals to Yamashina-sensei that she has come out to her parents and they took it badly, calling her "sick". She is very interested in Hinako's personal life as well, and only learns that her teacher once dated a woman also though she never elaborates further than that. Kawakubo eventually graduates, though it is a bitter moment for her as she leaves school without ever having her feelings for Hinako returned.