Which fictional character lives at 221B Baker Street?

221B Baker Street is the London address of the fictional detective Sherlock Holmes, created by author Sir Arthur Conan Doyle. In the United Kingdom, postal addresses with a number followed by a letter may indicate a separate address within a larger, often residential building. Baker Street in the late 19th century was a high-class residential district, and Holmes's apartment would probably have been part of a Georgian terrace. The residence was introduced in the novel A Study in Scarlet (1887). At the time the Holmes stories were published, addresses in Baker Street did not go as high as 221.

Source: Wikipedia