She is the wife of Shuichi Aizawa and mother of Yumi Aizawa.

She first appeared in episode eighteen when Aizawa arrives with a bruise on his head saying he had a little fight with her because Yumi was very young and he rarely slept at home. She appears at the end of the episode when she and Yumi see Aizawa sitting on a bench in the park. Eriko asks if he would be home for dinner because she had only bought food for her and her daughter. Soon after, Aizawa cries, Yumi asks her mother why he was crying.

Death Note: How to Read 13 says she and her daughter are usually sad because Aizawa overworked.