Izumi Shibusawa is a first-year student at Chidori High School and a founding member of the reinstated Rifle Shooting Club. She possesses long brown hair styled inward, reaching her shoulders and tied into a braid at the ends. Her teal-colored eyes and thin eyebrows are visible beneath her fringe. During shooting practice, she wears specialized rifle clothing.

Her background centers on a longstanding childhood friendship with Hikari Kokura, forged through their shared passion for rifle shooting. This mutual interest led them to enroll at Chidori High, where they collaborated to revive the disbanded Shooting Club. Izumi recruited Erika Meinohama, whom she remembered from a school ceremony, while Yukio Igarashi approached them independently; Izumi did not initially recognize Yukio.

Gentle, supportive, and exceptionally composed, Izumi is described by Hikari as reliable and level-headed. Her hobbies include reading—often reorganizing bookshelves when distracted—and cooking, with her confections frequently motivating Hikari during training. Izumi's calm demeanor balances Hikari's excitability, though she engages in playful interactions, such as humorously accepting Hikari’s marriage proposal before jokingly suggesting divorce during fireworks.

Throughout the series, Izumi serves as a steadfast support for the club: tutoring Hikari for exams, encouraging her shooting enthusiasm, and ensuring teammates' well-being, like covering them with blankets after study sessions. In competitions, her shooting averages around 9.5 per shot, below national-level competitors who consistently score in the 10-ring. This performance relegated her to a standby position during the national tournament after failing to qualify as a primary participant. Her surname "Shibusawa" combines the kanji for "astringent" (渋, *shibu*) and "marsh" (沢, *sawa*), while her given name "Izumi" (泉水) signifies "fountain" or "spring water".