Moeka China

Height: 158 cm (5'2")

As Akeno's childhood friend and a source of mutual encouragement, she aspires to become a Blue Mermaid. After enrolling at Yokosuka Girls' Marine High School, she is appointed captain of the Musashi.

She excels academically and possesses strong leadership qualities. It can be inferred that she applied to and passed the entrance exam for the Navigation Department.

Having been a model student since childhood—gifted with an exceptional memory and a diligent nature that allowed her to handle anything with ease—she had begun to lose interest in everything around her. However, befriending Akeno changed that completely; she came to feel that being with Akeno was the most exciting thing in the world. Consequently, while she may appear to be the "big sister" figure to Akeno at first glance, she is actually the one who relies more heavily on the other emotionally.

After entering junior high, both girls were taken in by new families and lived apart; however, their bond goes far beyond that of ordinary childhood friends—they are so close that they embrace whenever they reunite. During their junior high years, they kept in touch via email, and she even sent Akeno a self-made study guide to help her prepare for the marine high school entrance exam.

It appears her mother was a Blue Mermaid.