Kiku Sarasugawa, operating under the alias Benten-Okiku, belongs to her school's Better Fortune Research Organization club, a front for the secret Happy Seven group. She embodies the deity Benzaiten, one of the Seven Lucky Gods. Confident and outgoing, Kiku frequently flaunts her abilities with demonstrated skill, backing up her cocky attitude. She maintains a pretense of animosity towards fellow club member Amano Sakogami, persistently calling her "Ribbon Girl." In her transformed state, featuring detached sleeves and a distinctive design, Kiku wields a lute as her primary weapon. She joins Happy Seven missions combating Magatsugami—monsters that consume human negative emotions and misfortune—using her musical instrument-based fighting style. Alongside other members, each representing different deities, Kiku helps locate individuals plagued by extreme bad luck, confront the monsters worsening their plight, and neutralize these threats through coordinated action.