

Shinobu first met Kosaku Kawajiri in junior high school and dated him because her friends thought he was cool. She claims to have the type of character that is usually liked by cats. By the end of Part 4, she lovingly awaits his return but is unaware that both her original husband and the man who took his identity are gone. From cooking meals, stealing money for the landlord, and protecting her from Stray Cat, Shinobu's romantic affections for her "husband" are rekindled, excited by his sudden change in personality. However, once her husband's appearance is stolen, her relationship with her "husband" improved as his new sudden care for her. She is very pleased when he finally begins to return her affection. Though she resents her son for trapping her in her marriage, she occasionally reaches out to him, only to be ignored.

She wished for more excitement in her life and often lashed out at her husband and son out of frustration. While she felt no hatred towards Kosaku, her relationship with him was cold and full of regret. Shinobu has a personality closer to that of a younger woman than a responsible mother, detesting her marriage. She wears several different outfits throughout the series, most of them having skirts and patterns such as polka-dots. Sometimes, like in her first appearance, she will tie back several locks of hair that are part of her bangs.

Shinobu is a woman of seemingly average height and slim build, with hair that is parted to the right and tied back in a low ponytail.
