Suwa is Naho and Kakeru’s classmate and friend. He is very energetic and outgoing and he loves to hang out with his friends. He likes Naho but knows she likes Kakeru, so he supports them both. Suwa will become a very important person to her in her future, but 16-year-old Naho doesn’t know yet.
It is later revealed that he also received a letter from the future. The letter revealed that he and Naho were married and had a child.