Some fan theories are so bizarre that most of us don't even consider it a possibility. We've had some crazy fan theories that change the way we look at our favourite movies but we rarely come across original fan theories which are backed by some legitimate evidence. Moriarty is one of the most discussed figures of contemporary pop-culture and his escape from death still baffles us.

However, there's a possibility that the real identity of Moriarty in the show has been uncovered. Andrew Scott isn't Moriarty but a pawn in the bigger game. Sherlock Holmes' mother, Mrs Holmes, is Moriarty.

Source - Blogspot

Here are a few facts that help us validate this theory -

1. Moriarty is a Professor of Mathematics

Moriarty is a Professor of Mathematics in the original Conan Doyle stories - something that has not been carried over onto Sherlock with Andrew Scott's Jim Moriarty. However, in His Last Vow, we learn that Sherlock's mother is a genius mathematician. This is the first parallel you can draw between Moriarty and Mrs. Holmes.

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2. Moriarty and Mrs. Holmes have both written books that sound awfully similar

As seen in His Last Vow, Mrs. Holmes wrote a book called The Dynamics of Combustion. In the original stories, Moriarty was the one to author a book called The Dynamics of an Asteroid. This subtle little clue might just go a long way in the show.

Source - Phactual

Here's an excerpt from Sherlock's episode His Last Vow:

Mrs. Holmes wrote a book titled The Dynamics of Combustion by M. L. Holmes (so it must have been written after her marriage). Sherlock's father says of her, "Complete flake, my wife, but happens to be a genius" and also "unbelievably hot." She refers to the book as "that silly old thing".

Source - Express 3. Steven Moffat's interview about Moriarty's return Steven Moffat in his interviews repeats these lines - "Moriarty is back! I'm not saying that Moriarty is alive". He also keeps mentioning the huge hint in The Last Vow that apparently everyone missed. These subtle hints have gone unnoticed because those who've read the original novels don't obsess over the show. Source - AMC Network 4. Moriarty knows everything there is to know about Sherlock Mrs. Holmes has been around Mycroft and Sherlock for a long enough time to easily outsmart them. She is a really smart lady who definitely knows Sherlock very well. This is easily a trait of Moriarty. Plus she gave birth to Mycroft and Sherlock so she definitely knows her way around her smart kids. Source - Phactual 5. Moriarty is not just a person but an identity Moriarty is not an individual. Moriarty is an identity. Moriarty would never come out into the open to confront Sherlock Holmes. Andrew Scott's character is definitely not Moriarty but someone who pretends to be. Using him as diversion, Mrs Holmes has successfully stayed under the radar. Source - Tumblr 6. The confusion regarding Andrew Scott's death on top of the building We've seen how they've tried avoiding the truth behind Moriarty's and Sherlock's escape from death. This is clearly a sign that the reveal about Moriarty's identity would render that death pointless. This might make the job of the writers easy. Source - BBC 7. Sherlock's mother being Moriarty is the perfect con Nobody expects Mrs. Holmes to be Moriarty. This revelation has the potential to break the internet. The idea of Mrs. Holmes as Moriarty is so bizarre that even if someone were to make this assumption, he'd be termed as a crazy guy. This makes it the perfect con. Source - YBrikman

We don't believe that the theory is accurate. But I won't let my dreams be dreams!