A childhood friend of Jinta and Menma, and she likes Jintan.
Naruko displays a cold attitude towards Jinta, especially while in front of her friends, but is secretly worried about his wellbeing. Naruko is described as a person easily influenced by others, hanging out with and playing along with the actions of other girls around her even when she doesn't agree with them. She had admired Meiko, and strove to be like her when they were children, though she was simultaneously envious of her relationship with Jinta. She attends the same high school as Jinta and is closest to him at the start of the series, even dropping off homework for him while he refuses to attend class. She tells him that she is disappointed by his current lifestyle, but still shows lingering feelings, even painting her nails before she goes to see him. She doubts Meiko's return, but remains jealous of the fact that Jinta still looks only at her, as well as guilt for asking the question that led to Meiko drowning. Atsumu states that both of them were left behind and are trapped by their unrequited feelings for Jinta and Meiko.