Kageyama's first daughter (景山の長女 Kageyama no chōjo) is the eldest daughter of Kageyama and an unnamed mother.

She is an 18-year-old Japanese woman with a skinny build, pale skin, and long black hair. She is seen wearing a school uniform consisting of a grayish-yellow sweater vest, a long-sleeved light-gray dress shirt, a maroon necktie, and a navy-blue skirt.

Although she does not physically appear, she is briefly seen in a family photograph with her two siblings and parents. Around the time that her father Kageyama went on a business trip, her mother was concerned that she kept returning home later and later each night. When her father returned home, her mother asked Kageyama to talk to their 18-year-old daughter about her curfew, but he replied that it was his wife's responsibility.