Mashiro Munetani

Height: 159 cm (5'2")

She is the daughter of the Soya family, a prestigious lineage that has produced generations of Blue Mermaids. As the youngest of three sisters, she is a serious honor student who excels in every subject; however, she is incredibly unlucky—incidents include shifting her answers by one spot on an entrance exam and colliding with Akeno Misaki to fall into the sea right after enrolling. Consequently, she is constantly muttering, "I have no luck..."

She dislikes the nickname "Shiro-chan," given to her by Akeno, and prefers to be addressed as "Vice-Captain" or "Ms. Soya." Hiromi Kuroki looks up to her with admiration and frequently supports her.

While she maintains a serious and dignified demeanor, she loves cute things and keeps a large collection of stuffed animals in her room—which she ends up sharing with Wilhelmina. Incidentally, her favorite stuffed animal is a shark named Bruce.

As seen in the "specialty emblem" displayed on the right shoulder of her uniform, she applied to and passed the entrance exam for the Gunnery and Torpedo Department at Yokosuka Girls' Marine High School. As a result, she effectively performs the duties of the Gunnery and Torpedo Officer during combat.