Mashiro Isshiki is the mother of Akane Isshiki and Momo Isshiki. She was hospitalized seven years before the main events of the story following a factory explosion that also claimed the life of her husband. Her health gradually improves over the course of the series, and by its conclusion she is close to being discharged. Her role in the narrative is primarily as a background figure whose condition serves as an emotional anchor for her family, especially for Akane, who is motivated by a desire to see her mother recover. Mashiro’s personality is not extensively developed on screen, but she is portrayed as a kind and caring parent. She has no combat abilities or special powers. Her key relationships are with her daughters and her father-in-law, Kenjirou Isshiki. Because she appears only in a few scenes, she undergoes no significant character development and remains a supportive, off-screen presence for much of the story.