Jun Sasada is the diligent and efficient class president in Takashi Natsume's first-year class at Yowake High School. She has brown hair, green eyes, and wears glasses, typically securing her hair with a green hair clip. Her assertive nature in her role can sometimes come across as bossy. She persistently observes Natsume, convinced he can perceive supernatural beings despite his denials. Sasada experienced significant loss: her mother died during her childhood, and after her father remarried, he also passed away, leaving her to live with her stepfamily. During a "Trial of Courage" at an old schoolhouse, she lost an amulet gifted by her late mother. A yokai named Shigure, identifiable by a bucket worn over his head, retrieved it for her using a stick, explaining that "impure" beings like himself could not touch such a "blessed pure" object. Unable to identify Shigure at school, Sasada concluded he was a spirit and returned daily to the schoolhouse to thank him. When another "Trial of Courage" was held at the same schoolhouse slated for demolition, she pressured Natsume to participate, aiming to confirm her suspicions about his abilities. After classmates went missing due to Shigure's actions, she confronted Natsume directly and was rendered unconscious by Nyanko-sensei. She later apologized and revealed her impending move to the city due to her stepfather's job. Overhearing Nyanko-sensei (in human form) mention Shigure's name and connection to the Book of Friends, Sasada asked Natsume to convey her gratitude to Shigure for his past kindness, which had given her daily courage. Natsume relayed her message during the confrontation, helping Shigure find peace before he faded away. Though unable to see the yokai, Sasada sensed their connection as he bid farewell, an incident that remained a significant memory. In the manga continuity, she moved away shortly after this event. In the anime adaptation, she remained as a recurring member of Natsume's school friend group alongside Satoru Nishimura, Atsushi Kitamoto, Kaname Tanuma, and Tooru Taki. Her persistence continued in later anime appearances. She found an old bus ticket dropped by Natsume, questioned him about it, and followed him to a bus stop to ask about his destination. When questioned about her interest, she blushed and claimed a desire to see a yokai, referencing her experience at the schoolhouse. Kaname Tanuma distracted her, allowing Natsume to depart alone.