Tanimura Hina

Best friend/mother/daughter/sister of the protagonist (depending on what cheats are or aren't used). Can also be a catgirl, cowgirl, pirate or a combination of the three depending on what cheats are activated.

Spoiler

If she is Minorou's sister, she's a virgin because she fell for her brother several years ago when Minorou, Hatsune and her had played the "bottle's game" where Minorou had to kiss her and touch her chest as a pledge.