Misha confesses the shocking truth that, "At midnight on my 15th birthday, I’m going to disappear." Misha was never supposed to exist in this world in the first place, but due to Ivis Necron’s magic, she was living a transient life. She had resigned to her fate that she will only live for 15 years, but Anos tells her, "There are two things that I do not understand. Regret and saying that something is impossible." The misfit crushes the tragedy and unjust fate that binds the two sisters.

Everything started two thousand years ago. The situation suddenly shifts when the true identity of the man in the black mask, Avos Dilhevia, is revealed. Even after two thousand years, the wounds caused by the endless conflict between demons and humans have not been healed. The Demon King of Tyranny, Anos Voldigoad, makes a choice…