Tsuyuki
About
Tsuyuki is Mari and Tsutomu's mother, and Yukiko's grandmother. When Mari was young, Tsuyuki used to make a lot of negative comments on her appearance claiming that it was "for Mari's own good", leading to Mari's poor self esteem. Despite Mari outright stating it, she refuses to acknowledge that she treated Tsutomu better.
When asked by Yukiko, Tsuyuki confesses that she wanted to avoid raising Mari to be as conceited as one of Tsuyuki's classmates. Despite causing lasting damage to her mother's self esteem, Yukiko recognizes that her grandmother is a flawed human and did her best.