Kumiko is a former nurse, who is Amashiro Kiyomi's grandmother.
Amashiro Kiyomi is Amashiro Kiyomi's grandmother, and Amashiro Hiroto's mother. Since Kiyomi's parents are required to travel a lot for their jobs, Kiyomi lives with Kumiko most of the times. Kumiko cares for Kiyomi most of the time. Kumiko deeply cares for Kiyomi, which is why she always tries to teach her new things, like listening to heart instead of her brain. In the past, Kumiko worked as nurse, which today helps her to take care for Kiyomi but also for Loo, who stays at their mansion as well.
- Kumiko, Hiroto and Chinatsu are the only minor character from earth to learn about the girls' secret.