Otome Katou attends Sakakino Gakuen in class 1-4 and plays on the girls' basketball team. She has known Makoto Itou since their middle school days as classmates who often spent time together. Her family includes her father, the parishioners' representative at Haramihama Shrine, her mother Nadeshiko, and her younger sister Karen. Her father's womanizing and her mother's violent responses to his infidelities shaped Otome, fueling her hostility towards women she views as seducing men. Otome possesses an average height and a slim, athletic build. She has brown eyes and medium-length brown hair usually worn in a high ponytail with spiky bangs. Her bust measures 78 cm, noted as one of the smallest among main female characters. She is commonly seen in her school uniform or basketball gear. For summer events, she opts for casual wear like a green shirt with a fiery design, gray jeans, a hip scarf, and sometimes a red-white hoodie. Her personality is direct, headstrong, and authoritative. She tolerates only her own opinions and methods, associating solely with her trio of friends: Natsumi Koizumi, Minami Obuchi, and Kumi Mori. Together, they bully Kotonoha Katsura, whom Otome resents for her physical attractiveness and perceived use of her body to seduce men. This stems partly from Otome's complex about her smaller bust size compared to Kotonoha and Karen. Her aggression extends beyond Kotonoha; she assaulted Hanon Nijou in middle school after mistakenly believing Hanon fancied Makoto and verbally harassed Roka Kitsuregawa over Roka's mother's affair with Otome's father. Despite this challenging exterior, Otome displays tsundere traits, showing tenderness and shyness around Makoto. She has harbored a longstanding crush on him since junior high, joining the basketball club on his suggestion and studying hard to attend the same high school. Makoto, however, views her as "one of the guys" and historically dismissed her romantic advances as jokes. If they enter a relationship, Otome remains outspoken, leading to frequent arguments her friends attribute to her natural demeanor. Across media, Otome's involvement in bullying Kotonoha is consistent. In visual novel routes, she instigates Taisuke Sawanaga's rape of Kotonoha by falsely claiming Kotonoha desires sex but is too shy to admit it. She becomes ashamed if Makoto discovers her role, as he initially believes her incapable. During the school festival, she may invite Makoto to a break room, with their interaction varying by player choices. In the anime adaptation, Otome invites Makoto to a folk dance and then to a break room where they engage in implied sexual activity. She later ends the relationship after witnessing Makoto's indifference to Sekai's potential pregnancy, discarding a cherished photo of herself, Makoto, and Karen from middle school. During *Shiny Days*, Otome assists her family preparing for the Haramihama Shrine summer festival. Enlisting Karen's help, she arranges for Makoto to join the Youth Association to spend time with him. Her rivalry with Ai Yamagata—both having liked Makoto since middle school—intensifies, leading to conflicts. In one ending, Otome discovers Makoto's relationship with Karen; after Karen facilitates Otome's confession, the three engage in sexual activity. The Katou family discovers them, leading to Makoto being assaulted but allowed to continue dating the sisters. In *Cross Days*, Otome is seen bullying Roka Kitsuregawa at Gakuenmae. Hanon and Niki later explain to Yuuki Ashikaga that Otome targeted Roka due to projecting her family issues onto her, specifically Roka's mother's affair with Otome's father. Otome maintains a close-knit relationship with her friend trio, often discussing rumors and boys while coordinating harassment against Kotonoha. Her interactions with Makoto reveal a lingering closeness despite reduced contact; they occasionally talk for hours on the phone. Her dynamic with Karen involves typical sisterly interactions, while her rivalry with Ai Yamagata escalates to dangerous levels in *Island Days*. Trivia notes include the irony of her name ("Otome" meaning "maiden," contrasting her tomboyishness) and her status as the only heroine in the original *School Days* not to become pregnant in any route. A measurement error in the *Cross Days Visual Fan Book* listed her bust size incorrectly.