Oda Mao

Kousuke's older sister who hates all males, whether they are humans or animals. Because she doesn't want to breathe the same air as Kousuke, she moved to the dormitory after passing the school's entrance exam.

She hates males because they are filthy, how they smell, how they're so selfish and perverted, and because she never knows what they're thinking. She hates everything about males. Despite this, she is not a lesbian.
She especially likes using sex toys to pleasure herself.