蓬莱泉 瑠奈

A fifth/sixth grade primary school student and recent transfer at St. Michael's. Smart, mature and highly charismatic for her age, Runa has won many fans in her class but she is very interested with her teacher Takako and declares she belongs to her.

Runa harbors resentment over her older sister Rena, yet unseen in the story, who frequently leaves her alone while she goes out on business trips. Runa's older sister is Takako's former crush, which leads to the relationship between Runa and Takako once they meet for the first time in St. Michael's.