Denki

(from ebookjapan):

A chaotic extra-dimensional world where humans and fairies coexist. Attacked by man-eating giants, the man-buying demons flee to a village in desperation.

Meanwhile, the Black Rose Society, which has gathered together the ranks of the soldier class, joins forces with a monster who is mad for virgin skin, and slaughters the humans. Can the boy, who remembers only the name "Denki," triumph in the fierce battle against the Black Rose Society and the monsters?