Jamie Moriarty

Jamie Moriarty is Sherlock Holmes' nemisis. After Sherlock interrupted several of her plans when he worked for Scotland Yard, she tricked Sherlock into falling in love with her so she could study him, knowing her only as Irene Adler. Although the character is only seen in four episodes so far, she is the main antagonist of the first season, and her character (both as Irene Adler and as Moriarty) is mentioned in many episodes of Season One before she actually appears. Even after her arrest and imprisonment, she continues to have a great impact on him, and he writes letters back and forth with her because she is 'the only person he can relate to'. She is played by Natalie Dormer.