A sorrow we feel from losing our loved one, the fear of inevitable death, our hate for our nemesis, the anxiety and nervousness for the unknown— an example of negative emotions that doomed humanity to its demise. The descendants of Cains use this as a fertilizer for the Seed of Darkness implanted to grow and corrupt its host, resulting in a monster that spreads Chaos. Once a victim becomes a Fallen, their soul will never find salvation, and the only way to save them was to kill them using an Ego weapon, a weapon that's born with a soul. After spending five years as the disciple of Master Morian, Noah Ambert is sent to the Tower of Babel—an organization that unknown to ordinary people. It comprises of those willing to fight the Fallen and the Descendants of Cain—to become a Ego Master. It's up to Noah and his fellow Master to stop the Descendants of Cain's ultimate goal: the end of the world.