Mahou Senshi Sweet Knights: Heroine Ryoujoku Shirei / Sweet Warriors

The hentai is based on the visual novel of the same name from studio The Triangle Game. In the depths of our planet lies the underground world of Roa, where magic and sorcery thrive. However, currently it is engulfed in a territorial war between the kingdom of Gloria and the forces of the Zelu syndicate. Metzger, a young and respected officer in the Zelu army, receives an order from the command to make an expedition to the surface world. He must get to Earth, find and gain the trust of the "Sweet Knights", who are magical girls from the kingdom of Gloria. They are called to protect the sacred territory from the encroachments of the Zelu syndicate. Over time, Metzger discovers the knights' weaknesses and decides to kidnap the girls and turn them into sexual slaves.