Alr going book wise
In doyle's books,we do know that moriarty has an unamed brother.
And since bbc sherlock was based off the works of doyle and shi
I have a theory of his "alter ego" being just his brother (maybe a twin)
Why?
Jim himself usually has a light 5'o clock shadow,but as rich brook it seemed thicker
No one could grow a thicker stubble in a span of hours