The main character of The Hound of the Baskervilles is of course Sherlock Holmes.

Sherlock Holmes  is a fictional detective created by author and physician Sir Arthur Conan Doyle. A London-based "consulting detective" whose abilities border on the fantastic, Holmes is famous for his astute logical reasoning, his ability to adopt almost any disguise, and his use of forensic science skills to solve difficult cases.

Holmes, who first appeared in publication in 1887, was featured in four novels and 56 short stories. The first novel, A Study in Scarlet, appeared in Beeton's Christmas Annual in 1887 and the second, The Sign of the Four, in Lippincott's Monthly Magazine in 1890. The character grew tremendously in popularity with the first series of short stories in The Strand Magazine, beginning with A Scandal in Bohemia in 1891; further series of short stories and two novels published in serial form appeared between then and 1927. The stories cover a period from around 1880 up to 1914.

All but four stories are narrated by Holmes's friend and biographer, Dr. John H. Watson; two are narrated by Holmes himself ("The Blanched Soldier" and "The Lion's Mane") and two others are written in the third person ("The Mazarin Stone" and "His Last Bow"). In two stories ("The Musgrave Ritual" and "The Gloria Scott"), Holmes tells Watson the main story from his memories, while Watson becomes the narrator of the frame story. The first and fourth novels, A Study in Scarlet and The Valley of Fear, each include a long interval of omniscient narration recounting events unknown to either Holmes or Watson.
He likes solving very difficult cases and that is his hobbie

I like Sherlock Holmes because he is so ineligent and he can solve any case. He is like a superhero.