In 1989, I murdered Carl Powers. I became the world's only consulting criminal and work as an informal, sponsor and a mastermind. 

As a criminal genius, I have been described as an insane, masochistic and psychopathic individual. 

Sadly, you shouldn't flirt with me. I'm married to @madamina and she is also an insane and psychopathic individual.

I've done many things such as:
Sponsored Jeff Hope to start killing
Helped smuggle Black Lotus agents into London
Faked the death of Ian Monkford
Supplied poison to Raoul de Santos to help in the murder of Connie Prince
Helped Miss Wenceslas in faking the authenticity of the Vermeer painting
Advised Irene Adler on how to manipulate Sherlock and Mycroft
Leaked information to a terrorist cell about a US/UK counter-terrorist operation

Yes, I did just confess, but I can do that because I can open any door anywhere with a few tiny lines of computer code. No such thing as a private bank account now. They're all mine. No such thing as secrecy. I OWN secrecy. Nuclear codes? I could blow up NATO in alphabetical order. In a world of locked rooms, the man with the key is king. And, honey, you should see me in a crown.

Sherlock: "People have died."
Moriarty: "That's what people DO!"

"Every fairytale needs a good old-fashioned villain. You need me, or you're nothing."