The following is a list and description of the characters of Sherlock, a British television series that started airing on BBC One in July 2010. The series is a contemporary adaptation of the Sherlock Holmes stories by Sir Arthur Conan Doyle and was created by Steven Moffat and Mark Gatiss.
1 Louis Oliver and Tom Stoughton portray a young Sherlock Holmes in flashback scenes.
2 Aaron Richards portrays a young Mycroft Holmes in flashback scenes.
3 Indica Watson portrays a young Eurus Holmes in flashback scenes.
William Sherlock Scott Holmes (Benedict Cumberbatch) describes himself initially as "a consulting detective, the only one in the world", helping out Scotland Yard when they are out of their depth with cases (usually homicides). He appears as a tall, thin man with dark, curly hair. Like the original character, Sherlock is highly intelligent and able to deduce or abduce information from the small details.
Sherlock has a very unusual personality, and describes himself in the first episode "A Study in Pink", as a "high-functioning sociopath", a term he insists on in subsequent episodes. Others call him a "psychopath", and in "The Hounds of Baskerville", Watson tells Lestrade that he believes Sherlock has Asperger syndrome. This manifests itself in very poor people skills and the extremely rude manners Sherlock shows toward everyone he deals with. At times, he also seems to exhibit sensory sensitivities, associated with autism spectrum disorders, and occasionally exhibits "stimming" behaviors (pacing, hopping, spinning, rocking, making origami from serviettes, flapping a hand) when excited, upset, stressed, concentrating deeply, or overwhelmed. On two occasions in the episode The Hounds of Baskerville, he also appears to suffer from episodes of sensory overload and has minor meltdowns, and fidgeting with his hand after such an episode appears to soothe him. Also a characteristic of autism, Sherlock can be shown to have a very literal understanding of what is said to him – once, when after Sherlock tells Watson that he wants to go out that evening, Watson tells him that can't because he is going on a date, describing it as "two people who like each other [going] out and [having] fun", Sherlock replies that "That's what [he] was suggesting." Nonverbal communication also does not seem to come naturally to him, and he appears sometimes not to understand sarcasm. During the episode, The Sixth Thatchers, John and Lestrade have a sarcastic conversation during which they compare Sherlock's neediness and selfishness to that of John's infant daughter, and although Sherlock is able to tell that they are making a joke about him, he does not fully understand and after asking them if they are making a joke, admits that he "doesn't get it." He is also disdainful of the "typical" affectionate relationships he sees other people sharing, referring to them as "sentiment ... a chemical defect found on the losing side." He seems to admit that he does not understand sentiment and does not wish to, but, as seen below, he is shown to care deeply about his closest friends. Sherlock is, however, skilled at feigning emotion and is shown successfully manipulating strangers – mostly by playing on their weaknesses – into helping him or providing information useful for a case. His brother Mycroft, in the first episode, says Sherlock has the mind of a scholar or philosopher.