甘木ミク

The protagonist's older sister, same age as the protagonist.

She is a child from her mother's previous marriage, making her the protagonist's stepsister.

She finds her younger brother annoying. She has a selfish and tyrannical personality. Contrary to her appearance, she speaks harshly and is always particularly tough on her brother.

Unlike her mother, she has a complex about her significantly smaller chest.

She feels anxious about still not having a boyfriend and is currently looking for a lover.