Sakuraba Kaoru

She is a junior of the protagonist, and was Taeka's private tutor.
She is the oldest of the three girls at 19, and has no girly vibe at all.
Her calm, gentle demeanor and kind expression suit her, and she seems to have grown up in a somewhat sheltered environment.
She has excellent proportions, and how she is older than Satsuki and Taeka, she is like an older sister or mother to them.