Kotori Kureha plays rugby for Doshisha University as a first-year reserve back, wearing jersey number 21. He possesses a lean build, short blond hair, and dark blue eyes. Typically quiet and reserved, he openly dislikes hearing or saying his own name, requesting others avoid it frequently; this aversion reflects a deeper discomfort with his identity. Descriptions note he blends handsome boy qualities with subtle delinquent undertones, adding complexity to his silent demeanor.

Originally from Fukuoka South High School, he and Yayoi Tsudura were teammates before both enrolling at Doshisha. Their relationship extends beyond rugby; after an unspecified incident separated Kotori from his biological mother and sister during childhood, he lived with Yayoi's family. This arrangement provided warmth and stability, forging a bond where Yayoi assumed a protective, brotherly role.

A pivotal past event involved a woman identifying as a reporter visiting their home with a book that disturbed Kotori. This resurfaced trauma related to his family separation, causing visible psychological distress and further closing him off emotionally. The incident remains a source of inner conflict, contributing to his withdrawn nature and persistent emotional wounds.

Within the team, Kotori demonstrates attentiveness to collective goals, redirecting casual conversations toward upcoming matches. He primarily interacts with Yayoi, whose presence offers reassurance; their foundational relationship sees Yayoi consistently support Kotori against his struggles. Teammates note Kotori's ongoing battle with self-doubt regarding his physical stature, perceiving it as a rugby limitation despite his reserve position.

The etymology of his name reinforces thematic elements: "Kotori" combines the characters for "small" (小) and "bird" (鳥), while "Kureha" uses "give/do something for" (呉) and "feather" (羽). This linguistic construction evokes imagery of fragility and vulnerability paralleling his personality and backstory.