This world was originally a peaceful place. However, with the appearance of Ophikion, the ghost of prophecy, ghosts began to emerge, eventually leading to a massive infestation. Ghost Ranks: F-Rank: The weakest; even ordinary people can exorcise them with a simple talisman. E-Rank: Can be suppressed by a 5th-class exorcist. D-Rank: Requires basic exorcism equipment and specialized weapons. C-Rank: Capable of seizing a whole village; requires a 3rd-class exorcist. B-Rank: Requires a 2nd-class exorcist and advanced equipment. A-Rank: Can be suppressed by a single 1st-class exorcist, but high-quality gear is necessary. S-Rank: Requires multiple 1st-class exorcists; monitored closely by the Exorcism Association. SS-Rank: A threat to everyone; requires a 0-rank Special Class exorcist. SSS-Rank: World-ending level; can barely be sealed even if a vast number of exorcists are mobilized.

Current Blacklist of Wanted Ghosts by the Exorcism Association:

Zagan of Gold (S-Rank) [Active] Hopping 'Jiangshi' (S-Rank) [Sealed] Tentacle King 'Slenderman' (S-Rank) [Active] 'Eoduksini' in the Dark (S-Rank) [Sealed] Wood and Steel 'Gangcheol-mokgwi' (S-Rank) [Active] Ice Queen 'Yuki-onna' (S-Rank) [Active] Sand-wielding Crow 'Sandman' (SS-Rank) [Active] Goblin King 'Dueoksini' (SS-Rank) [Sealed] Petrifying Gaze 'Medusa' (SS-Rank) [Sealed] Fusion of Jiangshi and Zagan 'Zaganshi' (SS-Rank) [Prophesied] Origin of Prophecy 'Ophikion' (SSS-Rank) [Sealed] Fallen Archangel 'Jihaguk-daejeok' (SSS-Rank) [Awakened]

Exorcist Ranks: 5th-class Exorcist: Can handle simple ghost eliminations. 4th-class Exorcist: Can eliminate up to D-rank ghosts alone. 3rd-class Exorcist: Highly resilient; can easily handle C-rank ghosts. 2nd-class Exorcist: Recognized by the Association with a personalized license; handles B-rank ghosts. 1st-class Exorcist: Awarded a professional badge by the Association; can take down A-rank ghosts. 0-rank Exorcist: Capable of suppressing S-rank to SS-rank ghosts. Selected secretly by the Exorcism Association.