Coffret serves as the fairy companion to Erika Kurumi, Cure Marine. He possesses cyan hair and black eyes. His personality mirrors Erika's, characterized by hyperactive energy and a matching stubborn streak. This often sparks arguments where neither easily backs down, yet their bond remains resilient, typical of fairy-Cure partnerships. Coffret shares the vital duty of protecting the Tree of Hearts with Chypre, Tsubomi Hanasaki's fairy partner.

During the Rainbow Jewel events, Coffret leaves a note directing Tsubomi and Erika to Fairy Park, where mascots distribute Miracle Lights. Erika's angry reaction to his vague instructions frightens him until Tsubomi intervenes with comfort. Assisting with the lights at the park, Coffret's easily distracted nature causes minor disruptions when lights float away unattended.

When Fairy Park is attacked, Coffret becomes separated from Erika and Tsubomi. He later reunites with them in the Planetarium, enabling their transformation into Cure Blossom and Cure Marine to defend the Rainbow Jewel. Throughout the crisis, Coffret works alongside other mascots to locate partners and gather Miracle Lights, aiding in Fairy Park's restoration and Bottom's defeat. His dynamic with Erika showcases a partnership where surface conflicts never undermine their deep loyalty or effectiveness as guardians.