The main character, a college freshman just starting a new life in the School of Literature of Tama University. His parents passed away while he was young. He was raised by his sister Yuri. He was angry about his sister's marriage to a man with two daughters from prior marriage. When Yuri and her husband went missing, their three daughters had no one to turn to. Segawa decided to take them in and wants to become their guardian. He is surprising reliable, and even the little Hina got close to him quickly.