Kiriya Senshō is a second-year Japanese literature student at Seikan Women's University, residing in the "Goddess Dormitory." Raised in a family-run martial arts dojo alongside three younger brothers, she developed proficiency in judo, karate, and tai chi. This upbringing fostered her use of the masculine pronoun "boku" and a boyish demeanor, earning her the "Campus Prince" nickname for her popularity in cross-dressing events, where she once won a contest and later judged.

She sports medium-length red hair tied in high pigtails with forehead-framing bangs, yellow eyes, and favors Chinese-style clothing or non-girly attire, often maintaining a confident expression. Publicly, she projects stoic reliability and cheerfulness, acting as a protective older sister figure to dorm residents like Koshi Nagumo, initially treating him like a younger brother. Privately, she feels pressure to uphold others' admiration and harbors insecurities about her perceived masculinity, fearing she appears unattractive in feminine clothing.

Her secret passion for shoujo manga, discovered in college, causes her to lose control of her martial arts strength when engrossed in romantic stories, leading to accidental property damage like broken walls or floors. This occurred during an incident where she fell through the floor into Koshi's room while reading, revealing her hobby and prompting late-night interactions. Her sleep habits involve excessive tossing and turning.

Her relationship with Koshi evolves significantly: after he assists her family's Christmas party and offers a sincere gift, she nearly kisses him before being interrupted. Later, as fellow mikos during a New Year's event, Koshi defends her against littering delinquents, sustaining minor injuries. She intervenes to drive the offenders away, leading to a heartfelt confession of her self-image doubts. Koshi rejects her insecurities, affirming her attractiveness in women's clothing and strengthening their bond. This shifts her view of him from brotherly to romantic, causing increased embarrassment and girlish behavior around him, including blushing and emotional vulnerability.

She fears ghosts and maintains a competitive rivalry with dorm resident Atena Saotome. Her name combines the characters for "war/battle" (戦) and "blossom" (咲), referencing Norse Valkyries.