Mizuho is the mother of Izumi, Mitsuki, and Karin.

Compared to her husband, Mizuho is very young, having Izumi at the age of 16 and being age 30 during the story. Also in contrast to her husband, she is not concerned at all with two of her daughters in the hands of a perverted teenager, and will allow a love relationship between Izumi and either Anna (stating that "love has nothing to do with gender") or Yoshitaka (stating that he should "feel free to go crazy").

She and Mitsuki are very similar, as Mitsuki has learned almost everything from her mother.

(Wikipedia.org)