@Sujan_Dhakal @mistylavenda so I looked at the Wikipedia page for historical fiction and found this:
Historical fiction is a literary genre in which the plot takes place in a setting located in the past. Although the term is commonly used as a synonym for the historical novel , it can also be applied to other types of narrative, including theatre, opera, cinema, and television, as well as video games and graphic novels.
An essential element of historical fiction is that it is set in the past and pays attention to the manners, social conditions and other details of the depicted period.
I’m thinking I could add the tag then 
@Jess1973 I like it! That Moriarty/ Sherlock situation could add some wonderful angst 
I think it should definitely be a gothic/supernatural type story!! 
I was thinking Adler demon first, but then who should be the vampire? 
maybe for some really angsty material Lestrade is vampire hunter turned vampire? 
@Ghoslestat ooh ghost! Who should be a ghost then? 
Mycroft?