桐谷 夏妃

She is Ikumi's daughter and the same age as the protagonist, but because Natsuki was born two months later, she is considered his younger sister.

She is not happy about it and cannot stand being the younger sister of the protagonist, who is not very popular.

Therefore, she treats him ill, and like her mother, when her father is not around, she treats him as if he is her errand boy.

The protagonist's hypnotism makes her recognize him as her “favorite handsome brother,” and she starts to aggressively try to get his attention through aggressive body communication and pampering.