Kokone Kikogami is a member of the Verbalism Club associated with the organization DEAVA. She comes from a family that runs a venerable shrine in the Asagaya district of Tokyo. A kind and gentle person, she struggles with extreme shyness and often stutters, which makes ordinary conversation difficult for her. This timidity stems from a traumatic event in her childhood that robbed her of the confidence to speak assertively. Despite this, she possesses an exceptional singing voice and performs at a top-class level. Her personal dream is to become an actress, though her lack of self-assurance prevents her from pursuing it openly. Within the club, she is regarded as an idol and enjoys a dedicated following among its members.

In the conflict against the Menace of Japanese with Biological Kinetic energy, Kokone serves as a pilot of Vector machines, contributing her Verbalism power to form the giant mecha Aquarion and fight against the monsters. Her ability to bring the meaning of written characters to life through her voice makes her a valuable asset in battle. She harbors romantic feelings for the protagonist Akira Kaibuki and sometimes feels envious of Maia Tsukigane's closeness to him. Throughout the series, Kokone gradually overcomes her insecurities, learning to trust her own voice and gaining greater confidence in her abilities. Her development is marked by a growing willingness to speak up and support her comrades, both on and off the battlefield. Notable abilities include her high-level singing talent and her use of Verbalism to manifest the power of words in combat.