Harumi Fujiyoshi occupies seat 29 in class 2-F, defined by her dedicated creation of doujinshi, predominantly yaoi works exploring male-male romance and eroticism. A powerful coupling instinct drives her to envision pairings between male characters, with the Pine/Napple pairing reigning as her favorite. This extends to imagining explicit scenarios involving her teacher, Nozomu Itoshiki, and his friend.

Her name cleverly combines "fujoshi" (denoting female yaoi fans) and "Harumi," a nod to the former Tokyo location of Comiket before its relocation to Tokyo Big Sight. She possesses black hair reaching her shoulders and wears glasses. Despite attracting recruitment offers from multiple school sports clubs due to notable athletic prowess, she consistently declines, showing zero interest in athletics.

Harumi reacts strongly when others mention or mock her hobby, often becoming visibly annoyed or perversely enthusiastic about yaoi couplings. Socially, she exhibits bluntness, particularly regarding her interests. Her family includes three older brothers employed in the anime industry, and her mother identifies Harumi as an unplanned "accidental child."

A significant element of her past is her childhood friendship with classmate Chiri Kitsu. Chiri's hallucinations and paranoia isolated her from peers, making Harumi her sole childhood companion. This established a foundation for their later interactions despite Chiri's volatility. Within narrative developments, Harumi engages passionately in debates with fellow fujoshi over preferred couplings, such as Shizaya versus Izuo, reflecting her active engagement in fan culture dynamics.