If you notice any errors in the translations, please correct them.
English Translation (rough translation)
A long time ago, giant meteors rained from the sky and brought forth the mighty "demon king". The demon king could not be killed by "heroes" and wreaked havoc upon the world. A person called Lotta had discovered the demon king's weakness and helped to seal him away. A prophecy mentioned the Day of Resurrection, when the demon king would escape his prison and be reborn. Years passed and the prophecy came true. The demon king was reborn and free once again.
In order to protect the world, five brave heroines set out on a quest to defeat the demon king. Armed with the knowledge of the demon king's weakness, these brave virgin women vowed to seal (with the exception of Ennis, wishing to redeem him instead) the demon king awoke once again.