Simoun

In the world of Daikuuriku, all individuals are born female and decide their gender at 17. The theocratic state of Simulacrum is protected by magical aerial units known as Simoun, which can only be operated by girls who have not yet chosen their gender. These machines can unleash a powerful ability called "Ri Maajon," capable of wiping out many enemies simultaneously. When the industrial power Argentum invades to obtain the Simoun's secret, the Sibyllae—priestesses who pilot the Simoun—engage in an uneven war. The Sibyllae are allowed to delay choosing a permanent gender as long as they continue to fight. Aaeru, a resolute Sibylla with an enigmatic background, and Neviril, the commander of Chor Tempest, Simulacrum's top Simoun unit, guide their fellow pilots through challenges both in the air and within their group.