Keiko Koyabu advises the Tsugaru Shamisen Appreciation Club at Umezono Academy while teaching an unspecified subject there. Her involvement with the club began through personal motivation, not musical skill—she assumed the advisor role after developing a crush on its founder, Seiryu Kamiki, during his student years. This personal history anchors her to the club despite her lack of shamisen knowledge or experience. She fulfills organizational and supervisory duties for members Setsu Sawamura, Shuri Maeda, Yui Yamazato, Kaito Yaguchi, and Rai Nagamori.