Tamami Chanohata attends Seika Tandai Fusoku High School as a classmate and close friend of Kozue Aoba, holding inactive "ghost member" status alongside Kozue in the occult club. She constantly carries a camera to capture embarrassing moments, particularly targeting Kozue. Despite her ordinary appearance, she possesses significant physical strength. Her personality presents a perpetually smiling yet cold, sarcastic, cruel, manipulative, and condescending front toward those she deems her moral or intellectual inferiors – encompassing nearly everyone except Kozue and Kozue's alternate personalities. This behavior stems from extreme protectiveness fueled by her romantic feelings for Kozue and prior isolation attributed to her exceptional intellect. She habitually ends sentences with "desu" as a verbal tic.

Initially hostile toward Shiratori Ryuushi at Narutaki-sou, perceiving him as a threat to her bond with Kozue, Tamami eventually acknowledges Kozue's feelings for Shiratori and ceases her interference. Underlying emotional vulnerability surfaces, exemplified by her crying during Momono Megumi's departure. Her relationship with Megumi evolves into one of vitriolic best buds. By the manga's conclusion, she achieves professional success as a world-class photographer frequently undertaking international assignments. Her background includes overcoming social isolation caused by her genius-level intellect before forming her bond with Kozue. Her birthday is November 8, and she shares Kozue's age at the series' outset.