Many novels feature characters that are similar to ultimate villains, and "Sherlock Holmes" is no exception.
The ultimate villain of this novel is named Moriarty.
On the surface, he is a university professor and philosopher with a good reputation in the public eye.
However, behind the scenes, he is the head of a world criminal organization, a man with no conscience or morals, and a criminal genius whose intellect matches that of Sherlock Holmes!
He has created a vast criminal empire in London, England, with an underground network spreading across countries. Half of the cases in London are related to him, and after every crime, he leaves no trace, destroying all evidence unnoticed and escaping cleanly without fail. Even Holmes often hits a brick wall in dealing with him.
There has never been a direct description of Moriarty in the novel.
This character is mostly portrayed through Holmes's reports.
The next chapter Lin Yuan is to write is called "The Final Case."