Shirou's aunt, little sister of his mother. When the protagonist's real parents died, she wanted to take care of him, but she was still a student and her parents were against it as Shirou's parents marriage was opposed by his grandparents.
Now she's the owner of Sawako Brand, a new line of feminine products that are making a great success recently. As she has financial stability, she wants to be Shirou's guardian. When she finally meets him again after more than 7 years apart she starts to spoil him to make him want to go with her.