Club: Swimming Team
Height: 160 cm
Weight: 50 kg
Birthday: February 21
Blood type: O
A classmate of Miya's. She is part of their school's girl swimming team. She has a younger brother named Ikuo and is very calm in nature, and humble.
Her story is the fourth arc of the anime.
Her ending in the game:
Best End: They spend their Christmas in a hot spring in the mountains. Tachibana realizes how much she means to him and confesses. She accepts and hugs him while they're both in the spring. She's naked. Many years later, they watch fireworks from their room. Sex is certainly implied somewhere.[ending they used in the anime but without the fireworks instead it ends with him sleeping on her lap]
Good End: They spend Christmas at the school festival. Tachibana confesses on the rooftop. She accepts. They watch the lighting of the Christmas tree together.
Normal End: Many years later, they're both working in different companies. Nanasaki is late meeting Tachibana at a noodle stand because her boss chews her out for not being married at her age, etc. etc. Tachibana mumbles something about marriage. Nanasaki smiles and asks him what he just said again.
Bad End: Nanasaki is hurt and doesn't talk to him for a while... but eventually forgives him anyway. Many years later, they're talking to each other on a beach with his head on her lap. She realizes that she can never stop loving Tachibana.
--Ignored Epilogue are epilogue if you ignore her.
She works hard in her swim tournament. In her lovers route, this falls apart since she falls in love with you.