**"Underground River"**: It is not a physical river, but refers to a huge black industrial chain hidden underground in modern cities, consisting of illegal organ trading, human experimentation, and taboo magic. It flows like a hidden river in the shadows of the city, devouring innocent lives.
* **"Archives"**: refers to the confidential documents collected by the protagonist during the investigation that record the crimes and supernatural phenomena of the "Dark River". It is also a collection of clues connecting all cases.
* **Supernatural elements**: They are not traditional ghosts, but "distortions" that are the twisted products of "Underwater"'s inhumane experiments (such as organ grafting, consciousness fusion, and ancient soul refining). They have some supernormal abilities, but they suffer terribly and are living witnesses of sin.
The writing is awesome [Thinking]