Akari Watanabe is a high school student whose initial gyaru persona—outgoing, confident, and brash—masks her disappointment at being paired with Jirō Yakuin instead of her crush Minami Tenjin in a school marriage practical. Her true nature surfaces as kind, responsible, and caring, particularly in managing household chores and cooking during the practical. Despite academic procrastination, she demonstrates capability when focused, outperforming Jirō on tests he tutored her for.

Her appearance features waist-length pink hair often tied in twin buns, blue-green eyes, and a modified school uniform with exposed shoulders, accessorized by heart-shaped earrings and a leg scrunchie. Off-school, she favors revealing outfits but avoids dresses except to attract attention. Her frequently changing nail art reflects her passion for pursuing professional nail styling.

Akari's background includes a frequently absent father, leading her to prioritize emotional support for her mother and shaping her desire for a reliable partner. At Seishun Academy, Minami defending her from false accusations sparked her two-year crush. During the marriage practical, she cooperates with Jirō solely to earn partner-switching points but develops genuine feelings after Minami’s rejection and Jirō’s consistent presence, culminating in a formal confession and a shift toward a real relationship with him. She proactively deepens their bond through provocative outfits like a maid costume, initiating dates, and allowing physical proximity, yet exhibits jealousy when Jirō interacts with girls like Shiori Sakurazaka.

Her relationship with Jirō evolves from hostility—using nicknames like "Virgin-kun"—to vulnerability, seeking his comfort during fears of darkness, spiders, or thunderstorms. Friendships with Sachi Takamiya and Natsumi Ōhashi support her through romantic transitions. Despite her confident image and teasing use of attractiveness, she lacks romantic and sexual experience, expressing distress at being "left behind" and emphasizing commitment to true love over casual relationships, aligning with her disdain for the practical’s encouragement of multiple partners.