Hana Mitsui

The younger sister of the protagonist. The long-awaited daughter of the Mitsui family, and for that reason her parents named her with a name that also represents "flower"...but they didn't expect her to be stupid as one too. At home, she walks completely naked without any sense of shame given her lack of sexual knowledge, but when she went to live with his brother for summer vacation, she slowly began to discover new pleasures...