Momiji Hozuki is a middle school student with short brown hair, typically secured in a low-hanging topknot that evokes a samurai aesthetic; she wears it down in cold weather. Her brown eyes, 149 cm height, and 42 kg weight accompany noticeably less pronounced physical development than peers like Mahiro Oyama, Miyo Murosaki, or Kaede, prompting jokes about her flat chest. This trait enables her to skip bras casually, occasionally inciting envy. She favors shorts, t-shirts, or her school uniform, avoiding skirts or dresses unless shopping with others. Her masculine attire and physique often lead to misidentification as a boy, as occurred with Mahiro and Asahi Ōka. Anime renditions add light turquoise streaks to her hair. Kind yet tomboyish, Momiji excels athletically and competitively, frequently challenging Asahi to races despite shared academic struggles. She disdains feminine clothing but adopts a lower voice and hand signs when wearing "dashing" items like gothic lolita dresses, men’s kimonos, or an eyepatch. Deeply self-conscious about her flat chest, she finds solidarity in friends like Asahi and Nayuta Tenkawa. An intense fear of ghosts and horror stories triggers accidents where she wets herself. She exhibits protectiveness and jealousy, especially regarding Mahiro’s attention toward others. Her long-standing friendship with Asahi Ōka began in elementary school when Asahi—mistaking Momiji for a boy—nicknamed her "Momijiro" and praised her topknot. Momiji reciprocated by styling Asahi’s hair into side pigtails. They bonded over activities like frog-watching after rain, puddle-jumping, and soccer matches with classmates Yuta Sakurada and Minato Senkawa. Post-soccer baths at Momiji’s apartment revealed Asahi’s early confusion about her anatomy. Both later attended Yotsuba University Affiliated Junior High School, forming a close trio with Miyo Murosaki. Momiji shares a supportive relationship with her older sister Kaede Hozuki, bonding over fried shrimp and matching keychains while envying Kaede’s figure. Within her friend group, Momiji develops a crush on Mahiro Oyama after assisting him during an errand. Her affection manifests through physical mishaps—like tripping and groping Mahiro’s breast—and jealousy when Mahiro interacts closely with others, such as intercepting food exchanges between Mahiro, Asahi, or Miyo to insist he tries hers. Unaware of Mahiro’s original male identity, she once checked his crotch during a hot spring trip; his smooth anatomy and feminine behavior later eased her suspicions. She proactively integrates Nayuta into their second-year class, bonding over shared flat-chestedness. Her dynamic with Asahi remains playfully competitive, while Miyo encourages her romantic pursuits. Key involvements include her introduction alongside Kaede in manga Chapter 10 and deepening interactions with Mahiro in Chapter 11. Notable incidents encompass a sleepover where Asahi’s ghost story caused Momiji to wet herself from fear, online gaming sessions where she switched from her real name to the username "One-Eyed Suigetsu," and an extra manga story where accidental ingestion of Mihari’s experimental drug temporarily gave her male anatomy—sparking confusion and near-violence toward Mahiro. She participates in beach trips, school physicals, and Mahiro’s surprise birthday party, often leading group activities. Vulnerable moments—like experimenting with hair extensions or envying developed peers—contrast her consistent athleticism and loyalty.