She is the science teacher and also one of the mothers of Chitose. An inventor who loves to try her inventions on the boy and also to protect him from her childhood friend Kanna
Out of all the mothers Kisaragi is the one that is most odd, when you look at her all you see is she a crazy inventor. Underneath all this madness she is actually a kind hearted person who loves anything cute and her son who she most looks after. Her inventions are classed under a version number, prototype version 1.2 for example.
She is in charge of protecting the house and to stop strangers from finding out there secret, as students and teachers living together is considered wrong. During her childhood she had a friend called Kaana, who both promised to take over the world when they grew up, but since then things have changed. Kaana returns to confront Kisaragi about their dream, but is confused when she sees a boy with Kisaragi. Kaana instantly falls in love with Chitose and vows to kidnap him, but with Kisaragi looking after him it’s a hard task.