Mikoto Rikudou is leading a mundane life as an average high school student who barely notices the enigmatic apparitions of creatures known as "demons" in his city. However, his world turns upside down when he discovers that the quietest classmate is, in fact, one of these beings. Amidst a conflict with these creatures, he is transported into their realm and undergoes a metamorphosis, becoming one of them. Along with his newfound powers comes a daunting truth: he must kill others to save his own life.
