Sherlock Holmes is the legendary great detective who solves even the most baffling cases with astute observation, deductive reasoning and very little people skills. As a "consulting detective," he favors reason and logic above all else and makes very few personal attachments beyond those that benefit him. He calls himself a "high functioning sociopath" because he does not make friends or understand emotions very well, beyond what can be studied. He would make a superior criminal if he were so inclined, but instead he assists the police, and Detective Inspector Greg Lestrade, on their most baffling cases.
Because he has no interest in emotions, he makes no effort to protect those of other people and often comes across as rude, blunt or even cruel, especially to Molly Hooper, the coroner, who has a crush on him.
In addition to Molly, the other people in the world he cares about are Mrs. Hudson, his landlady, who tolerates him keeping science experiments in the fridge and shooting holes in the walls; Detective Inspector Greg Lestrade with New Scotland Yard and Dr. John Watson, who starts out as his roommate and quickly becomes his assistant and chronicler on cases.
Sherlock has a brother, Mycroft, from whom he is estranged. Mycroft goes so far as to refer to himself as
Sherlock's arch enemy, yet they do help each other out when it is absolutely necessary. Sherlock's actual nemesis is master criminal James Moriarty, who is as intelligent as Sherlock, but uses his wits for crime. Sherlock doesn't have girlfriends, but is intrigued by Irene Adler, an intelligent criminal and high end escort.
Background: Lives at 221B Baker Street. In the Sir Arthur Conan Doyle stories Sherlock used cocaine, in this version his addictive vice is nicotine, which he is trying to give up, although he thinks it keeps his brain "active."