Amnesiac Ant Sith was cast into the City of Light by the system. Recruited by Charles, he became embroiled in a demon hunt. Possessing a strange immortality, he joins Rab in his battle against demons. However, he discovers that Ethan, a poor man, has transformed into a demon seeking revenge after being exploited. He also encounters Hedforkward, a demon master capable of summoning mirror worlds. Along the way, Ant navigates the rules of the Church of Light and struggles with his own humanity. He witnesses the complexities of factory owner Ursula, and in the midst of his battles with demons, he discovers the truth about his identity. Ultimately, he personally ends Ethan's suffering and resists Hedforkward's temptations. Within the shadows of the City of Light, he hides his own secrets while protecting this world where good and evil intertwine as a part-time demon hunter.