The character of Moriarty as Holmes's greatest enemy was introduced primarily as a narrative device to enable Conan Doyle to kill off Sherlock Holmes, and only featured directly in two of the Sherlock Holmes stories. However, in more recent derivative work he is often given a greater prominence and treated as Holmes's primary antagonist.
To be honest NP, I have tried to read "A Study in Scarlet " sadly for my Taste it's
so slow and Old Fashioned ( In its writing style ) that I've never read a full Sherlock
Although I do watch anything with the character in it, from the Old Hammer "Hound of the Baskervilles"
Through the J Brett series to Sherlock and Elementary ( Only the Pilot episode, so far ).
In many ways I suppose Moriaty is Like Blofeld as Many people think he's in Many stories.
It's odd, because Study in Scarlet is much better in the Sherlock series and brilliantly riffs on the novella.
However, you should try the short story Adventures of Sherlock Holmes, if you don't like one there's another. But true, they are a tough read at first, with Holmes' new visitor offloading a lot of info about the case, 2-3 pages, while H & W sit and listen. But there are some nice sinister tales in it, esp as the book goes on. Initially they are a bit underwhelming. And Irene Adler only appears in one story (and she's not in the buff! )
Bond: Mr. Mathis, there's something that's been worrying me...
Bond: Well, you're a French police inspector, yet you speak with an Italian accent.
Mathis: Mamma mia, it worries me, too.