Three years ago, a sickness known as Daemonblight befell the land. The sickness turns people into Daemons, and the world has fallen into an age of chaos. Even then, in a remote region of the Kingdom, the protagonist Velvet lived with her family in relative comfort. A night came when a red moon rose, and she was betrayed by Artorius, who was once her savior. She lost her family, while a mysterious power that consumed demons possessed her left arm. A measure of order returned to the world after Artorius founded the Abbey and the Exorcists. Artorius is hailed as the world's savior, but Velvet harbored only anger for him.
— Description from AniList community (anilist.co).
