Yoshino Koiwai

Maid of Adagaki household. She seems to be a clumsy girl and is always pushed around by Aki.

Yoshino later admits she was jealous of the friendship between Masamune and Aki. It was revealed that Yoshino had disguised herself as Aki eight years before, and rejected Masamune, giving him the nickname "piggy" or "tonsoku (pig's foot)" in the original Japanese.
Makabe calls her "shishou" (師匠) which means master or teacher.