Youma no Kishi

Far beyond time, after many battles with the Dark King, after many deeds and longings, the land of the elves was destroyed, and the blood of the old royal family was cut off. Except for two people, a young child and his protector, who escaped to the......other world...
A black shadow is seen just before falling asleep. Finally, the black shadow spoke to Marie. "Tomorrow, I will borrow your shadow. The time is near when the "darkness" will begin to move."
The next day, during a test in the classroom, a classmate suddenly began to fall asleep. Behind them, the "nightmare" that Marie had seen as a child appeared. Behind the terrified Marie, that shadow appears. As if to protect her...