Chitsuru Yotsuba

She is Yuuichi's stepmother. They are about the same age and she had been a widow since Yuuichi's father passed away. She had been living alone since Yuuichi is married to Kanami. Yuuichi realized that widows are often lonely without their husband, after his visitation to Suzuka's house - he saw her masturbating alone while watching pornography and he decided to comfort her loneliness with his male side.