Amakami Kanako

The eldest of the 3 sisters. Homeroom teacher of the protagonist.

Has a frank personality but is relied and supported by her co-workers and students.

However, has an opposite impression in her younger brother's mind. After coming home, loiters around wearing only a shirt and a piece of underwear. Cleaning, laundry and even preparations of making food, everything is left for her brother to do.

She is number 1 in popularity inside the school because of her appearance and personality. But she has no interest in any other man except her brother.

Teases the protagonist even inside the school. When catches the sight of him, tries to casually touch him or begins sexually harassing him. Other guys shows signs of jealousy but the protagonist himself feels very embarrassed and perplexed.