Sennen Sensou Aigis: Gekka no Hanayome  

Millennium War Aigis: Bride Under the Moonlight, 千年戦争アイギス 月下の花嫁

After many years passed since Aigis put an end to the conflict between humans and demons, the prince of Logres, a descendant of the hero, lived in peace. On one particular day, his fiancée, Kaguya from the east, came to him. However, before they could discuss marriage, demons attacked, seizing the royal capital with their power. The prince and his allies barely managed to escape along with Kaguya. They decided to retake the seized capital.