Neviril is the Sibylla Aurea, and the Regina of Chor Tempest. She has a reputation for being the best Auriga in the entire Simoun fleet, and is the object of admiration of both the other sibyllae and the cadets aboard Arcus Prima. She is so revered that junior sibyllae are reprimanded for addressing her without an honorific even in her absence. She is the daughter of Halconf, the chief administrator of Simulacrum&#039;s government. She and Amuria were very close, and she is devastated by the loss of her beloved partner.

In the peaceful theocracy of Simulicram, everyone is born female. At age 19, each maiden undergoes a special ceremony where she chooses her sex. However, only Pairs of maiden priestesses can synchronize with the ancient flying ships known as Simoun needed to defend Simulicram. These Pairs refrain from undergoing the ceremony as long as they wish to keep piloting their Simoun. 
Aer is recruited to be a Simoun pilot after a terrifying attack by an enemy nation decimates the squadron known as Chor Tempest. To earn her wings she needs to find her way into the heart of Neviril, Regina of Chor Tempest. But Neviril's heart still belongs to her previous Pair, lost in the battle when she attempted a forbidden Simoun maneuver. 
(Source: Media Blasters)

In the world of Daikuuriku, everyone is born female, and chooses which sex they wish to become at age 17. In this world, the peaceful theocracy of Simulacrum is guarded by magical flying machines called "Simoun", which can only be piloted by young girls who haven't chosen a sex yet. The Simoun can activate a magical power known as "Ri Maajon" that can destroy large numbers of enemies at once. When the industrialized nation of Argentum decides that it needs to invade Simulacrum to acquire the secret of the Simoun, war breaks out, drawing the Simoun "Sibyllae" (priestesses who fly the Simoun) into a lopsided battle. Because the war is raging, the Sibyllae are granted an exemption from choosing a permanent sex for as long as they're willing to keep flying. Aaeru, a determined young Sibylla with a mysterious past, and Neviril, the leader of Chor Tempest, Simulacrum's most elite Simoun squadron, must lead their fellow priestesses through conflict both within their ranks and in the sky.

An alternate comedy version of Simoun.