Manatsu Akoya is a fifteen-year-old crew member aboard the commercial warship Pascal Magi in a near-future world reshaped by a permanent hypercane known as the Grand Roar. She is the twin sister of Mashu Akoya, and the two share a close bond, often working together during missions. Manatsu has short blonde hair typically tied in pigtails and blue eyes, and she is notably small in stature, standing only 1.32 meters tall and weighing 30 kilograms. Her primary role on the ship is that of a gunner and communications operator, handling both weapon systems and ship-to-ship or ship-to-shore communications during combat. She is cheerful and mischievous, enjoying playing tricks on others alongside her sister, and she also takes genuine pleasure in combat situations. Her motivations are rooted in loyalty to her fellow crew members and a desire to protect the Pascal Magi from pirates and other threats. Manatsu maintains a particularly strong relationship with Mashu, with the twins sharing interests such as using the same cosmetics and coordinating their pranks. She also interacts frequently with the ship’s captain, Nanaha Misaki, and other crew members, contributing to the overall team dynamic. Throughout the series, Manatsu demonstrates competence under pressure as a gunner, and her development is tied to the various battles the crew faces, which test and reinforce her dedication to her duties and her companions. Notable abilities include her marksmanship with the ship’s weaponry and her adept handling of communications equipment during combat operations.