Setoyama-senpai, an upperclassman at Samejima Private Academy, sports blonde hair and striking pink eyes. She often joins Gotō-sensei for morning chats, where she openly criticizes smokers as "idiots" and voices her disdain for cigarettes. Her dynamic with Momo Shinozuka includes playful teasing about Momo’s crush on Gotō-sensei, subtly revealing her awareness of the younger student’s feelings. These brief interactions highlight her observant nature within the academy’s episodic narrative framework.