Ranko Kurusugawa, daughter of the wealthy Kurusugawa group family, serves as her high school's student council president. She projects a self-styled "ojousama aura," radiating superiority and entitlement. Her appearance features long blonde wavy hair with spiky bangs and ringlet sidehair, blue tsurime-shaped eyes, and a slim pale teenage body standing 162cm tall with a 93-56-90 cm bust-waist-hips ratio and a G-cup bust. She typically wears an elaborate school uniform adorned with ribbons, a ribbon tie, thigh-high stockings, and a brooch; she also appears in military-style uniforms with kevlar armor and a kemonomimi headband.

Arrogant and money-obsessed, Ranko habitually uses "watakushi" to convey formality and self-importance. She firmly believes every problem has a financial solution, often dismissing challenges with her signature phrase about money. Viewing herself as the "school queen," she expects homage to her status. Initially, she looks down on protagonist Kazuya, refusing to remember his name correctly and relying on her two maids to correct her mispronunciations. However, recognizing him as a rival after he launches his campaign to conquer their classmates, she begins addressing him by his proper name.

Her development shifts from dismissiveness to direct competition. She perceives Kazuya's conquests as a challenge to her authority and confidently confronts him with a sexual competition. Her ever-present maids imitate her every movement and assist in maintaining her image, including correcting her previous disregard for Kazuya's name once she deems him worthy. Her wealthy background enables expensive hobbies and reinforces her worldview where financial power dictates social dynamics. Her documented background centers on her heiress status, student council presidency, and unwavering reliance on wealth and status to navigate conflicts.