Sherlock Holmes is a fictional character created by Sir Arthur Conan Doyle in the late 19th century. Throughout Doyle’s stories, there is only one mention of Sherlock’s siblings, and that is a reference to an older brother named Mycroft Holmes.
Mycroft is introduced in the story “The Adventure of the Greek Interpreter,” which was first published in 1893. In the story, Mycroft is described as being seven years older than Sherlock and possessing a remarkable intellect similar to his brother’s. However, Mycroft is portrayed as being even more reclusive and less active than Sherlock, often preferring to stay indoors and work from his home in London’s Pall Mall.
While Mycroft is the only sibling of Sherlock’s who is mentioned by name in Doyle’s original stories, there are a few instances where other siblings are alluded to. In “The Adventure of the Musgrave Ritual,” for example, Sherlock mentions that he has a younger brother named “Mortal” who is a diplomat in the British government. However, this character is never seen or mentioned again in any of Doyle’s other stories.
In addition to Mortal, there are a few other siblings who are mentioned briefly in various adaptations of the Sherlock Holmes stories. In the BBC TV series “Sherlock,” for example, it is revealed that Sherlock has an older sister named Eurus Holmes, who is introduced in the fourth season. Eurus is portrayed as being even more brilliant than Mycroft and Sherlock, but also more dangerous and unstable.
Overall, while there are a few references to Sherlock’s siblings throughout various adaptations of the Holmes stories, the only sibling who is explicitly named and developed in Doyle’s original work is Mycroft Holmes.